static int ep_call_nested(struct nested_calls *ncalls,
			  int (*nproc)(void *, void *, int), void *priv,
			  void *cookie, void *ctx)
{
	int error, call_nests = 0;
	unsigned long flags;
	struct list_head *lsthead = &ncalls->tasks_call_list;
	struct nested_call_node *tncur;
	struct nested_call_node tnode;

	spin_lock_irqsave(&ncalls->lock, flags);

	/*
	 * Try to see if the current task is already inside this wakeup call.
	 * We use a list here, since the population inside this set is always
	 * very much limited.
	 */
	list_for_each_entry(tncur, lsthead, llink) {
		if (tncur->ctx == ctx &&
		    (tncur->cookie == cookie || ++call_nests > EP_MAX_NESTS)) {
			/*
			 * Ops ... loop detected or maximum nest level reached.
			 * We abort this wake by breaking the cycle itself.
			 */
			error = -1;
			goto out_unlock;
		}
	}

	/* Add the current task and cookie to the list */
	tnode.ctx = ctx;
	tnode.cookie = cookie;
	list_add(&tnode.llink, lsthead);

	spin_unlock_irqrestore(&ncalls->lock, flags);

	/* Call the nested function */
	error = (*nproc)(priv, cookie, call_nests);

	/* Remove the current task from the list */
	spin_lock_irqsave(&ncalls->lock, flags);
	list_del(&tnode.llink);
out_unlock:
	spin_unlock_irqrestore(&ncalls->lock, flags);

	return error;
}

#define EP_MAX_NESTS 4

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_UNACTIVE_PTR ((void *) -1L)

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}

struct eppoll_entry {
	/* List header used to link this structure to the "struct epitem" */
	struct list_head llink;

	/* The "base" pointer is set to the container "struct epitem" */
	struct epitem *base;

	/*
	 * Wait queue item that will be linked to the target file wait
	 * queue head.
	 */
	wait_queue_entry_t wait;

	/* The wait queue head that linked the "wait" wait queue item */
	wait_queue_head_t *whead;
}

struct ep_pqueue {
	poll_table pt;
	struct epitem *epi;
}


static int ep_send_events(struct eventpoll *ep,
			  struct epoll_event __user *events, int maxevents)
{
	struct ep_send_events_data esed;

	esed.maxevents = maxevents;
	esed.events = events;

	ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false);
	return esed.res;
}

do_epoll_ctl(): clean the failure exits up a bit

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}

struct eppoll_entry {
	/* List header used to link this structure to the "struct epitem" */
	struct list_head llink;

	/* The "base" pointer is set to the container "struct epitem" */
	struct epitem *base;

	/*
	 * Wait queue item that will be linked to the target file wait
	 * queue head.
	 */
	wait_queue_entry_t wait;

	/* The wait queue head that linked the "wait" wait queue item */
	wait_queue_head_t *whead;
}

struct ep_pqueue {
	poll_table pt;
	struct epitem *epi;
}

struct ep_send_events_data {
	int maxevents;
	struct epoll_event __user *events;
	int res;
}

static long max_user_watches __read_mostly;


static void ep_show_fdinfo(struct seq_file *m, struct file *f)
{
	struct eventpoll *ep = f->private_data;
	struct rb_node *rbp;

	mutex_lock(&ep->mtx);
	for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
		struct epitem *epi = rb_entry(rbp, struct epitem, rbn);
		struct inode *inode = file_inode(epi->ffd.file);

		seq_printf(m, "tfd: %8d events: %8x data: %16llx "
			   " pos:%lli ino:%lx sdev:%x\n",
			   epi->ffd.fd, epi->event.events,
			   (long long)epi->event.data,
			   (long long)epi->ffd.file->f_pos,
			   inode->i_ino, inode->i_sb->s_dev);
		if (seq_has_overflowed(m))
			break;
	}
	mutex_unlock(&ep->mtx);
}

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_UNACTIVE_PTR ((void *) -1L)

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}

struct eppoll_entry {
	/* List header used to link this structure to the "struct epitem" */
	struct list_head llink;

	/* The "base" pointer is set to the container "struct epitem" */
	struct epitem *base;

	/*
	 * Wait queue item that will be linked to the target file wait
	 * queue head.
	 */
	wait_queue_entry_t wait;

	/* The wait queue head that linked the "wait" wait queue item */
	wait_queue_head_t *whead;
}

struct ep_pqueue {
	poll_table pt;
	struct epitem *epi;
}

struct ep_send_events_data {
	int maxevents;
	struct epoll_event __user *events;
	int res;
}


static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi)
{
	int kcmp;
	struct rb_node **p = &ep->rbr.rb_root.rb_node, *parent = NULL;
	struct epitem *epic;
	bool leftmost = true;

	while (*p) {
		parent = *p;
		epic = rb_entry(parent, struct epitem, rbn);
		kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd);
		if (kcmp > 0) {
			p = &parent->rb_right;
			leftmost = false;
		} else
			p = &parent->rb_left;
	}
	rb_link_node(&epi->rbn, parent, p);
	rb_insert_color_cached(&epi->rbn, &ep->rbr, leftmost);
}


static void path_count_init(void)
{
	int i;

	for (i = 0; i < PATH_ARR_SIZE; i++)
		path_count[i] = 0;
}


static inline int epoll_mutex_lock(struct mutex *mutex, int depth,
				   bool nonblock)
{
	if (!nonblock) {
		mutex_lock_nested(mutex, depth);
		return 0;
	}
	if (mutex_trylock(mutex))
		return 0;
	return -EAGAIN;
}


static int reverse_path_check_proc(void *priv, void *cookie, int call_nests)
{
	int error = 0;
	struct file *file = priv;
	struct file *child_file;
	struct epitem *epi;

	/* CTL_DEL can remove links here, but that can't increase our count */
	rcu_read_lock();
	list_for_each_entry_rcu(epi, &file->f_ep_links, fllink) {
		child_file = epi->ep->file;
		if (is_file_epoll(child_file)) {
			if (list_empty(&child_file->f_ep_links)) {
				if (path_count_inc(call_nests)) {
					error = -1;
					break;
				}
			} else {
				error = ep_call_nested(&poll_loop_ncalls,
							reverse_path_check_proc,
							child_file, child_file,
							current);
			}
			if (error != 0)
				break;
		} else {
			printk(KERN_ERR "reverse_path_check_proc: "
				"file is not an ep!\n");
		}
	}
	rcu_read_unlock();
	return error;
}


SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
		int, maxevents, int, timeout, const sigset_t __user *, sigmask,
		size_t, sigsetsize)
{
	int error;

	/*
	 * If the caller wants a certain signal mask to be set during the wait,
	 * we apply it here.
	 */
	error = set_user_sigmask(sigmask, sigsetsize);
	if (error)
		return error;

	error = do_epoll_wait(epfd, events, maxevents, timeout);
	restore_saved_sigmask_unless(error == -EINTR);

	return error;
}

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}

struct eppoll_entry {
	/* List header used to link this structure to the "struct epitem" */
	struct list_head llink;

	/* The "base" pointer is set to the container "struct epitem" */
	struct epitem *base;

	/*
	 * Wait queue item that will be linked to the target file wait
	 * queue head.
	 */
	wait_queue_entry_t wait;

	/* The wait queue head that linked the "wait" wait queue item */
	wait_queue_head_t *whead;
}

struct ep_pqueue {
	poll_table pt;
	struct epitem *epi;
}

struct ep_send_events_data {
	int maxevents;
	struct epoll_event __user *events;
	int res;
}

static struct nested_calls poll_loop_ncalls;


COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
			struct epoll_event __user *, events,
			int, maxevents, int, timeout,
			const compat_sigset_t __user *, sigmask,
			compat_size_t, sigsetsize)
{
	long err;

	/*
	 * If the caller wants a certain signal mask to be set during the wait,
	 * we apply it here.
	 */
	err = set_compat_user_sigmask(sigmask, sigsetsize);
	if (err)
		return err;

	err = do_epoll_wait(epfd, events, maxevents, timeout);
	restore_saved_sigmask_unless(err == -EINTR);

	return err;
}


static int __init eventpoll_init(void)
{
	struct sysinfo si;

	si_meminfo(&si);
	/*
	 * Allows top 4% of lomem to be allocated for epoll watches (per user).
	 */
	max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) /
		EP_ITEM_COST;
	BUG_ON(max_user_watches < 0);

	/*
	 * Initialize the structure used to perform epoll file descriptor
	 * inclusion loops checks.
	 */
	ep_nested_calls_init(&poll_loop_ncalls);

	/*
	 * We can have many thousands of epitems, so prevent this from
	 * using an extra cache line on 64-bit (and smaller) CPUs
	 */
	BUILD_BUG_ON(sizeof(void *) <= 8 && sizeof(struct epitem) > 128);

	/* Allocates slab cache used to allocate "struct epitem" items */
	epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem),
			0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);

	/* Allocates slab cache used to allocate "struct eppoll_entry" */
	pwq_cache = kmem_cache_create("eventpoll_pwq",
		sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL);

	return 0;
}


static void ep_free(struct eventpoll *ep)
{
	struct rb_node *rbp;
	struct epitem *epi;

	/* We need to release all tasks waiting for these file */
	if (waitqueue_active(&ep->poll_wait))
		ep_poll_safewake(ep, NULL);

	/*
	 * We need to lock this because we could be hit by
	 * eventpoll_release_file() while we're freeing the "struct eventpoll".
	 * We do not need to hold "ep->mtx" here because the epoll file
	 * is on the way to be removed and no one has references to it
	 * anymore. The only hit might come from eventpoll_release_file() but
	 * holding "epmutex" is sufficient here.
	 */
	mutex_lock(&epmutex);

	/*
	 * Walks through the whole tree by unregistering poll callbacks.
	 */
	for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
		epi = rb_entry(rbp, struct epitem, rbn);

		ep_unregister_pollwait(ep, epi);
		cond_resched();
	}

	/*
	 * Walks through the whole tree by freeing each "struct epitem". At this
	 * point we are sure no poll callbacks will be lingering around, and also by
	 * holding "epmutex" we can be sure that no file cleanup code will hit
	 * us during this operation. So we can avoid the lock on "ep->lock".
	 * We do not need to lock ep->mtx, either, we only do it to prevent
	 * a lockdep warning.
	 */
	mutex_lock(&ep->mtx);
	while ((rbp = rb_first_cached(&ep->rbr)) != NULL) {
		epi = rb_entry(rbp, struct epitem, rbn);
		ep_remove(ep, epi);
		cond_resched();
	}
	mutex_unlock(&ep->mtx);

	mutex_unlock(&epmutex);
	mutex_destroy(&ep->mtx);
	free_uid(ep->user);
	wakeup_source_unregister(ep->ws);
	kfree(ep);
}


static void clear_tfile_check_list(void)
{
	struct file *file;

	/* first clear the tfile_check_list */
	while (!list_empty(&tfile_check_list)) {
		file = list_first_entry(&tfile_check_list, struct file,
					f_tfile_llink);
		list_del_init(&file->f_tfile_llink);
		fput(file);
	}
	INIT_LIST_HEAD(&tfile_check_list);
}


static __poll_t ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
			       void *priv)
{
	struct ep_send_events_data *esed = priv;
	__poll_t revents;
	struct epitem *epi, *tmp;
	struct epoll_event __user *uevent = esed->events;
	struct wakeup_source *ws;
	poll_table pt;

	init_poll_funcptr(&pt, NULL);
	esed->res = 0;

	/*
	 * We can loop without lock because we are passed a task private list.
	 * Items cannot vanish during the loop because ep_scan_ready_list() is
	 * holding "mtx" during this call.
	 */
	lockdep_assert_held(&ep->mtx);

	list_for_each_entry_safe(epi, tmp, head, rdllink) {
		if (esed->res >= esed->maxevents)
			break;

		/*
		 * Activate ep->ws before deactivating epi->ws to prevent
		 * triggering auto-suspend here (in case we reactive epi->ws
		 * below).
		 *
		 * This could be rearranged to delay the deactivation of epi->ws
		 * instead, but then epi->ws would temporarily be out of sync
		 * with ep_is_linked().
		 */
		ws = ep_wakeup_source(epi);
		if (ws) {
			if (ws->active)
				__pm_stay_awake(ep->ws);
			__pm_relax(ws);
		}

		list_del_init(&epi->rdllink);

		/*
		 * If the event mask intersect the caller-requested one,
		 * deliver the event to userspace. Again, ep_scan_ready_list()
		 * is holding ep->mtx, so no operations coming from userspace
		 * can change the item.
		 */
		revents = ep_item_poll(epi, &pt, 1);
		if (!revents)
			continue;

		if (__put_user(revents, &uevent->events) ||
		    __put_user(epi->event.data, &uevent->data)) {
			list_add(&epi->rdllink, head);
			ep_pm_stay_awake(epi);
			if (!esed->res)
				esed->res = -EFAULT;
			return 0;
		}
		esed->res++;
		uevent++;
		if (epi->event.events & EPOLLONESHOT)
			epi->event.events &= EP_PRIVATE_BITS;
		else if (!(epi->event.events & EPOLLET)) {
			/*
			 * If this file has been added with Level
			 * Trigger mode, we need to insert back inside
			 * the ready list, so that the next call to
			 * epoll_wait() will check again the events
			 * availability. At this point, no one can insert
			 * into ep->rdllist besides us. The epoll_ctl()
			 * callers are locked out by
			 * ep_scan_ready_list() holding "mtx" and the
			 * poll callback will queue them in ep->ovflist.
			 */
			list_add_tail(&epi->rdllink, &ep->rdllist);
			ep_pm_stay_awake(epi);
		}
	}

	return 0;
}

#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE)

#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | EPOLLERR | EPOLLHUP | \
				EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE)

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_UNACTIVE_PTR ((void *) -1L)

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}


static inline bool list_add_tail_lockless(struct list_head *new,
					  struct list_head *head)
{
	struct list_head *prev;

	/*
	 * This is simple 'new->next = head' operation, but cmpxchg()
	 * is used in order to detect that same element has been just
	 * added to the list from another CPU: the winner observes
	 * new->next == new.
	 */
	if (cmpxchg(&new->next, new, head) != new)
		return false;

	/*
	 * Initially ->next of a new element must be updated with the head
	 * (we are inserting to the tail) and only then pointers are atomically
	 * exchanged.  XCHG guarantees memory ordering, thus ->next should be
	 * updated before pointers are actually swapped and pointers are
	 * swapped before prev->next is updated.
	 */

	prev = xchg(&head->prev, new);

	/*
	 * It is safe to modify prev->next and new->prev, because a new element
	 * is added only to the tail and new->next is updated before XCHG.
	 */

	prev->next = new;
	new->prev = prev;

	return true;
}


static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
		   int maxevents, long timeout)
{
	int res = 0, eavail, timed_out = 0;
	u64 slack = 0;
	wait_queue_entry_t wait;
	ktime_t expires, *to = NULL;

	lockdep_assert_irqs_enabled();

	if (timeout > 0) {
		struct timespec64 end_time = ep_set_mstimeout(timeout);

		slack = select_estimate_accuracy(&end_time);
		to = &expires;
		*to = timespec64_to_ktime(end_time);
	} else if (timeout == 0) {
		/*
		 * Avoid the unnecessary trip to the wait queue loop, if the
		 * caller specified a non blocking operation. We still need
		 * lock because we could race and not see an epi being added
		 * to the ready list while in irq callback. Thus incorrectly
		 * returning 0 back to userspace.
		 */
		timed_out = 1;

		write_lock_irq(&ep->lock);
		eavail = ep_events_available(ep);
		write_unlock_irq(&ep->lock);

		goto send_events;
	}

fetch_events:

	if (!ep_events_available(ep))
		ep_busy_loop(ep, timed_out);

	eavail = ep_events_available(ep);
	if (eavail)
		goto send_events;

	/*
	 * Busy poll timed out.  Drop NAPI ID for now, we can add
	 * it back in when we have moved a socket with a valid NAPI
	 * ID onto the ready list.
	 */
	ep_reset_busy_poll_napi_id(ep);

	do {
		/*
		 * Internally init_wait() uses autoremove_wake_function(),
		 * thus wait entry is removed from the wait queue on each
		 * wakeup. Why it is important? In case of several waiters
		 * each new wakeup will hit the next waiter, giving it the
		 * chance to harvest new event. Otherwise wakeup can be
		 * lost. This is also good performance-wise, because on
		 * normal wakeup path no need to call __remove_wait_queue()
		 * explicitly, thus ep->lock is not taken, which halts the
		 * event delivery.
		 */
		init_wait(&wait);

		write_lock_irq(&ep->lock);
		/*
		 * Barrierless variant, waitqueue_active() is called under
		 * the same lock on wakeup ep_poll_callback() side, so it
		 * is safe to avoid an explicit barrier.
		 */
		__set_current_state(TASK_INTERRUPTIBLE);

		/*
		 * Do the final check under the lock. ep_scan_ready_list()
		 * plays with two lists (->rdllist and ->ovflist) and there
		 * is always a race when both lists are empty for short
		 * period of time although events are pending, so lock is
		 * important.
		 */
		eavail = ep_events_available(ep);
		if (!eavail) {
			if (signal_pending(current))
				res = -EINTR;
			else
				__add_wait_queue_exclusive(&ep->wq, &wait);
		}
		write_unlock_irq(&ep->lock);

		if (eavail || res)
			break;

		if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) {
			timed_out = 1;
			break;
		}

		/* We were woken up, thus go and try to harvest some events */
		eavail = 1;

	} while (0);

	__set_current_state(TASK_RUNNING);

	if (!list_empty_careful(&wait.entry)) {
		write_lock_irq(&ep->lock);
		__remove_wait_queue(&ep->wq, &wait);
		write_unlock_irq(&ep->lock);
	}

send_events:
	if (fatal_signal_pending(current)) {
		/*
		 * Always short-circuit for fatal signals to allow
		 * threads to make a timely exit without the chance of
		 * finding more events available and fetching
		 * repeatedly.
		 */
		res = -EINTR;
	}
	/*
	 * Try to transfer events to user space. In case we get 0 events and
	 * there's still timeout left over, we go trying again in search of
	 * more luck.
	 */
	if (!res && eavail &&
	    !(res = ep_send_events(ep, events, maxevents)) && !timed_out)
		goto fetch_events;

	return res;
}


static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)
{
	struct rb_node *rbp;
	struct epitem *epi;

	for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
		epi = rb_entry(rbp, struct epitem, rbn);
		if (epi->ffd.fd == tfd) {
			if (toff == 0)
				return epi;
			else
				toff--;
		}
		cond_resched();
	}

	return NULL;
}


static noinline void ep_destroy_wakeup_source(struct epitem *epi)
{
	struct wakeup_source *ws = ep_wakeup_source(epi);

	RCU_INIT_POINTER(epi->ws, NULL);

	/*
	 * wait for ep_pm_stay_awake_rcu to finish, synchronize_rcu is
	 * used internally by wakeup_source_remove, too (called by
	 * wakeup_source_unregister), so we cannot use call_rcu
	 */
	synchronize_rcu();
	wakeup_source_unregister(ws);
}


static inline void ep_pm_stay_awake_rcu(struct epitem *epi)
{
	struct wakeup_source *ws;

	rcu_read_lock();
	ws = rcu_dereference(epi->ws);
	if (ws)
		__pm_stay_awake(ws);
	rcu_read_unlock();
}


static void ep_busy_loop(struct eventpoll *ep, int nonblock)
{
	unsigned int napi_id = READ_ONCE(ep->napi_id);

	if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on())
		napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep);
}


static inline void ep_pm_stay_awake(struct epitem *epi)
{
	struct wakeup_source *ws = ep_wakeup_source(epi);

	if (ws)
		__pm_stay_awake(ws);
}


static int reverse_path_check(void)
{
	int error = 0;
	struct file *current_file;

	/* let's call this for all tfiles */
	list_for_each_entry(current_file, &tfile_check_list, f_tfile_llink) {
		path_count_init();
		error = ep_call_nested(&poll_loop_ncalls,
					reverse_path_check_proc, current_file,
					current_file, current);
		if (error)
			break;
	}
	return error;
}


static inline int ep_is_linked(struct epitem *epi)
{
	return !list_empty(&epi->rdllink);
}


static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
{
	int kcmp;
	struct rb_node *rbp;
	struct epitem *epi, *epir = NULL;
	struct epoll_filefd ffd;

	ep_set_ffd(&ffd, file, fd);
	for (rbp = ep->rbr.rb_root.rb_node; rbp; ) {
		epi = rb_entry(rbp, struct epitem, rbn);
		kcmp = ep_cmp_ffd(&ffd, &epi->ffd);
		if (kcmp > 0)
			rbp = rbp->rb_right;
		else if (kcmp < 0)
			rbp = rbp->rb_left;
		else {
			epir = epi;
			break;
		}
	}

	return epir;
}


static inline bool ep_has_wakeup_source(struct epitem *epi)
{
	return rcu_access_pointer(epi->ws) ? true : false;
}


static void ep_nested_calls_init(struct nested_calls *ncalls)
{
	INIT_LIST_HEAD(&ncalls->tasks_call_list);
	spin_lock_init(&ncalls->lock);
}


static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
{
}


static int path_count_inc(int nests)
{
	/* Allow an arbitrary number of depth 1 paths */
	if (nests == 0)
		return 0;

	if (++path_count[nests] > path_limits[nests])
		return -1;
	return 0;
}


int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
		 bool nonblock)
{
	int error;
	int full_check = 0;
	struct fd f, tf;
	struct eventpoll *ep;
	struct epitem *epi;
	struct eventpoll *tep = NULL;

	error = -EBADF;
	f = fdget(epfd);
	if (!f.file)
		goto error_return;

	/* Get the "struct file *" for the target file */
	tf = fdget(fd);
	if (!tf.file)
		goto error_fput;

	/* The target file descriptor must support poll */
	error = -EPERM;
	if (!file_can_poll(tf.file))
		goto error_tgt_fput;

	/* Check if EPOLLWAKEUP is allowed */
	if (ep_op_has_event(op))
		ep_take_care_of_epollwakeup(epds);

	/*
	 * We have to check that the file structure underneath the file descriptor
	 * the user passed to us _is_ an eventpoll file. And also we do not permit
	 * adding an epoll file descriptor inside itself.
	 */
	error = -EINVAL;
	if (f.file == tf.file || !is_file_epoll(f.file))
		goto error_tgt_fput;

	/*
	 * epoll adds to the wakeup queue at EPOLL_CTL_ADD time only,
	 * so EPOLLEXCLUSIVE is not allowed for a EPOLL_CTL_MOD operation.
	 * Also, we do not currently supported nested exclusive wakeups.
	 */
	if (ep_op_has_event(op) && (epds->events & EPOLLEXCLUSIVE)) {
		if (op == EPOLL_CTL_MOD)
			goto error_tgt_fput;
		if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) ||
				(epds->events & ~EPOLLEXCLUSIVE_OK_BITS)))
			goto error_tgt_fput;
	}

	/*
	 * At this point it is safe to assume that the "private_data" contains
	 * our own data structure.
	 */
	ep = f.file->private_data;

	/*
	 * When we insert an epoll file descriptor, inside another epoll file
	 * descriptor, there is the change of creating closed loops, which are
	 * better be handled here, than in more critical paths. While we are
	 * checking for loops we also determine the list of files reachable
	 * and hang them on the tfile_check_list, so we can check that we
	 * haven't created too many possible wakeup paths.
	 *
	 * We do not need to take the global 'epumutex' on EPOLL_CTL_ADD when
	 * the epoll file descriptor is attaching directly to a wakeup source,
	 * unless the epoll file descriptor is nested. The purpose of taking the
	 * 'epmutex' on add is to prevent complex toplogies such as loops and
	 * deep wakeup paths from forming in parallel through multiple
	 * EPOLL_CTL_ADD operations.
	 */
	error = epoll_mutex_lock(&ep->mtx, 0, nonblock);
	if (error)
		goto error_tgt_fput;
	if (op == EPOLL_CTL_ADD) {
		if (!list_empty(&f.file->f_ep_links) ||
						is_file_epoll(tf.file)) {
			mutex_unlock(&ep->mtx);
			error = epoll_mutex_lock(&epmutex, 0, nonblock);
			if (error)
				goto error_tgt_fput;
			full_check = 1;
			if (is_file_epoll(tf.file)) {
				error = -ELOOP;
				if (ep_loop_check(ep, tf.file) != 0)
					goto error_tgt_fput;
			} else {
				get_file(tf.file);
				list_add(&tf.file->f_tfile_llink,
							&tfile_check_list);
			}
			error = epoll_mutex_lock(&ep->mtx, 0, nonblock);
			if (error)
				goto error_tgt_fput;
			if (is_file_epoll(tf.file)) {
				tep = tf.file->private_data;
				error = epoll_mutex_lock(&tep->mtx, 1, nonblock);
				if (error) {
					mutex_unlock(&ep->mtx);
					goto error_tgt_fput;
				}
			}
		}
	}

	/*
	 * Try to lookup the file inside our RB tree, Since we grabbed "mtx"
	 * above, we can be sure to be able to use the item looked up by
	 * ep_find() till we release the mutex.
	 */
	epi = ep_find(ep, tf.file, fd);

	error = -EINVAL;
	switch (op) {
	case EPOLL_CTL_ADD:
		if (!epi) {
			epds->events |= EPOLLERR | EPOLLHUP;
			error = ep_insert(ep, epds, tf.file, fd, full_check);
		} else
			error = -EEXIST;
		break;
	case EPOLL_CTL_DEL:
		if (epi)
			error = ep_remove(ep, epi);
		else
			error = -ENOENT;
		break;
	case EPOLL_CTL_MOD:
		if (epi) {
			if (!(epi->event.events & EPOLLEXCLUSIVE)) {
				epds->events |= EPOLLERR | EPOLLHUP;
				error = ep_modify(ep, epi, epds);
			}
		} else
			error = -ENOENT;
		break;
	}
	if (tep != NULL)
		mutex_unlock(&tep->mtx);
	mutex_unlock(&ep->mtx);

error_tgt_fput:
	if (full_check) {
		clear_tfile_check_list();
		mutex_unlock(&epmutex);
	}

	fdput(tf);
error_fput:
	fdput(f);
error_return:

	return error;
}

#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE)

#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | EPOLLERR | EPOLLHUP | \
				EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE)

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}


static bool ep_busy_loop_end(void *p, unsigned long start_time)
{
	struct eventpoll *ep = p;

	return ep_events_available(ep) || busy_loop_timeout(start_time);
}


static void ep_remove_wait_queue(struct eppoll_entry *pwq)
{
	wait_queue_head_t *whead;

	rcu_read_lock();
	/*
	 * If it is cleared by POLLFREE, it should be rcu-safe.
	 * If we read NULL we need a barrier paired with
	 * smp_store_release() in ep_poll_callback(), otherwise
	 * we rely on whead->lock.
	 */
	whead = smp_load_acquire(&pwq->whead);
	if (whead)
		remove_wait_queue(whead, &pwq->wait);
	rcu_read_unlock();
}


void eventpoll_release_file(struct file *file)
{
	struct eventpoll *ep;
	struct epitem *epi, *next;

	/*
	 * We don't want to get "file->f_lock" because it is not
	 * necessary. It is not necessary because we're in the "struct file"
	 * cleanup path, and this means that no one is using this file anymore.
	 * So, for example, epoll_ctl() cannot hit here since if we reach this
	 * point, the file counter already went to zero and fget() would fail.
	 * The only hit might come from ep_free() but by holding the mutex
	 * will correctly serialize the operation. We do need to acquire
	 * "ep->mtx" after "epmutex" because ep_remove() requires it when called
	 * from anywhere but ep_free().
	 *
	 * Besides, ep_remove() acquires the lock, so we can't hold it here.
	 */
	mutex_lock(&epmutex);
	list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) {
		ep = epi->ep;
		mutex_lock_nested(&ep->mtx, 0);
		ep_remove(ep, epi);
		mutex_unlock(&ep->mtx);
	}
	mutex_unlock(&epmutex);
}


static inline int ep_cmp_ffd(struct epoll_filefd *p1,
			     struct epoll_filefd *p2)
{
	return (p1->file > p2->file ? +1:
	        (p1->file < p2->file ? -1 : p1->fd - p2->fd));
}


static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
	int pwake = 0;
	struct epitem *epi = ep_item_from_wait(wait);
	struct eventpoll *ep = epi->ep;
	__poll_t pollflags = key_to_poll(key);
	unsigned long flags;
	int ewake = 0;

	read_lock_irqsave(&ep->lock, flags);

	ep_set_busy_poll_napi_id(epi);

	/*
	 * If the event mask does not contain any poll(2) event, we consider the
	 * descriptor to be disabled. This condition is likely the effect of the
	 * EPOLLONESHOT bit that disables the descriptor when an event is received,
	 * until the next EPOLL_CTL_MOD will be issued.
	 */
	if (!(epi->event.events & ~EP_PRIVATE_BITS))
		goto out_unlock;

	/*
	 * Check the events coming with the callback. At this stage, not
	 * every device reports the events in the "key" parameter of the
	 * callback. We need to be able to handle both cases here, hence the
	 * test for "key" != NULL before the event match test.
	 */
	if (pollflags && !(pollflags & epi->event.events))
		goto out_unlock;

	/*
	 * If we are transferring events to userspace, we can hold no locks
	 * (because we're accessing user memory, and because of linux f_op->poll()
	 * semantics). All the events that happen during that period of time are
	 * chained in ep->ovflist and requeued later on.
	 */
	if (READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR) {
		if (chain_epi_lockless(epi))
			ep_pm_stay_awake_rcu(epi);
	} else if (!ep_is_linked(epi)) {
		/* In the usual case, add event to ready list. */
		if (list_add_tail_lockless(&epi->rdllink, &ep->rdllist))
			ep_pm_stay_awake_rcu(epi);
	}

	/*
	 * Wake up ( if active ) both the eventpoll wait list and the ->poll()
	 * wait list.
	 */
	if (waitqueue_active(&ep->wq)) {
		if ((epi->event.events & EPOLLEXCLUSIVE) &&
					!(pollflags & POLLFREE)) {
			switch (pollflags & EPOLLINOUT_BITS) {
			case EPOLLIN:
				if (epi->event.events & EPOLLIN)
					ewake = 1;
				break;
			case EPOLLOUT:
				if (epi->event.events & EPOLLOUT)
					ewake = 1;
				break;
			case 0:
				ewake = 1;
				break;
			}
		}
		wake_up(&ep->wq);
	}
	if (waitqueue_active(&ep->poll_wait))
		pwake++;

out_unlock:
	read_unlock_irqrestore(&ep->lock, flags);

	/* We have to call this outside the lock */
	if (pwake)
		ep_poll_safewake(ep, epi);

	if (!(epi->event.events & EPOLLEXCLUSIVE))
		ewake = 1;

	if (pollflags & POLLFREE) {
		/*
		 * If we race with ep_remove_wait_queue() it can miss
		 * ->whead = NULL and do another remove_wait_queue() after
		 * us, so we can't use __remove_wait_queue().
		 */
		list_del_init(&wait->entry);
		/*
		 * ->whead != NULL protects us from the race with ep_free()
		 * or ep_remove(), ep_remove_wait_queue() takes whead->lock
		 * held by the caller. Once we nullify it, nothing protects
		 * ep/epi or even wait.
		 */
		smp_store_release(&ep_pwq_from_wait(wait)->whead, NULL);
	}

	return ewake;
}

#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE)

#define EPOLLINOUT_BITS (EPOLLIN | EPOLLOUT)

#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | EPOLLERR | EPOLLHUP | \
				EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE)

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_UNACTIVE_PTR ((void *) -1L)

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}


static int ep_remove(struct eventpoll *ep, struct epitem *epi)
{
	struct file *file = epi->ffd.file;

	lockdep_assert_irqs_enabled();

	/*
	 * Removes poll wait queue hooks.
	 */
	ep_unregister_pollwait(ep, epi);

	/* Remove the current item from the list of epoll hooks */
	spin_lock(&file->f_lock);
	list_del_rcu(&epi->fllink);
	spin_unlock(&file->f_lock);

	rb_erase_cached(&epi->rbn, &ep->rbr);

	write_lock_irq(&ep->lock);
	if (ep_is_linked(epi))
		list_del_init(&epi->rdllink);
	write_unlock_irq(&ep->lock);

	wakeup_source_unregister(ep_wakeup_source(epi));
	/*
	 * At this point it is safe to free the eventpoll item. Use the union
	 * field epi->rcu, since we are trying to minimize the size of
	 * 'struct epitem'. The 'rbn' field is no longer in use. Protected by
	 * ep->mtx. The rcu read side, reverse_path_check_proc(), does not make
	 * use of the rbn field.
	 */
	call_rcu(&epi->rcu, epi_rcu_free);

	atomic_long_dec(&ep->user->epoll_watches);

	return 0;
}


static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi)
{
	struct eventpoll *ep_src;
	unsigned long flags;
	u8 nests = 0;

	/*
	 * To set the subclass or nesting level for spin_lock_irqsave_nested()
	 * it might be natural to create a per-cpu nest count. However, since
	 * we can recurse on ep->poll_wait.lock, and a non-raw spinlock can
	 * schedule() in the -rt kernel, the per-cpu variable are no longer
	 * protected. Thus, we are introducing a per eventpoll nest field.
	 * If we are not being call from ep_poll_callback(), epi is NULL and
	 * we are at the first level of nesting, 0. Otherwise, we are being
	 * called from ep_poll_callback() and if a previous wakeup source is
	 * not an epoll file itself, we are at depth 1 since the wakeup source
	 * is depth 0. If the wakeup source is a previous epoll file in the
	 * wakeup chain then we use its nests value and record ours as
	 * nests + 1. The previous epoll file nests value is stable since its
	 * already holding its own poll_wait.lock.
	 */
	if (epi) {
		if ((is_file_epoll(epi->ffd.file))) {
			ep_src = epi->ffd.file->private_data;
			nests = ep_src->nests;
		} else {
			nests = 1;
		}
	}
	spin_lock_irqsave_nested(&ep->poll_wait.lock, flags, nests);
	ep->nests = nests + 1;
	wake_up_locked_poll(&ep->poll_wait, EPOLLIN);
	ep->nests = 0;
	spin_unlock_irqrestore(&ep->poll_wait.lock, flags);
}

#define EPOLLINOUT_BITS (EPOLLIN | EPOLLOUT)

#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))

#define EP_UNACTIVE_PTR ((void *) -1L)

#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))

struct epoll_filefd {
	struct file *file;
	int fd;
} __packed;

struct nested_call_node {
	struct list_head llink;
	void *cookie;
	void *ctx;
}

struct nested_calls {
	struct list_head tasks_call_list;
	spinlock_t lock;
}

struct epitem {
	union {
		/* RB tree node links this structure to the eventpoll RB tree */
		struct rb_node rbn;
		/* Used to free the struct epitem */
		struct rcu_head rcu;
	};

	/* List header used to link this structure to the eventpoll ready list */
	struct list_head rdllink;

	/*
	 * Works together "struct eventpoll"->ovflist in keeping the
	 * single linked chain of items.
	 */
	struct epitem *next;

	/* The file descriptor information this item refers to */
	struct epoll_filefd ffd;

	/* Number of active wait queue attached to poll operations */
	int nwait;

	/* List containing poll wait queues */
	struct list_head pwqlist;

	/* The "container" of this item */
	struct eventpoll *ep;

	/* List header used to link this item to the "struct file" items list */
	struct list_head fllink;

	/* wakeup_source used when EPOLLWAKEUP is set */
	struct wakeup_source __rcu *ws;

	/* The structure that describe the interested events and the source fd */
	struct epoll_event event;
}

struct eventpoll {
	/*
	 * This mutex is used to ensure that files are not removed
	 * while epoll is using them. This is held during the event
	 * collection loop, the file cleanup path, the epoll file exit
	 * code and the ctl operations.
	 */
	struct mutex mtx;

	/* Wait queue used by sys_epoll_wait() */
	wait_queue_head_t wq;

	/* Wait queue used by file->poll() */
	wait_queue_head_t poll_wait;

	/* List of ready file descriptors */
	struct list_head rdllist;

	/* Lock which protects rdllist and ovflist */
	rwlock_t lock;

	/* RB tree root used to store monitored fd structs */
	struct rb_root_cached rbr;

	/*
	 * This is a single linked list that chains all the "struct epitem" that
	 * happened while transferring ready events to userspace w/out
	 * holding ->lock.
	 */
	struct epitem *ovflist;

	/* wakeup_source used when ep_scan_ready_list is running */
	struct wakeup_source *ws;

	/* The user that created the eventpoll descriptor */
	struct user_struct *user;

	struct file *file;

	/* used to optimize loop detection check */
	struct list_head visited_list_link;
	int visited;

#ifdef CONFIG_NET_RX_BUSY_POLL
	/* used to track busy poll napi_id */
	unsigned int napi_id;
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/* tracks wakeup nests for lockdep validation */
	u8 nests;
#endif
}

struct eppoll_entry {
	/* List header used to link this structure to the "struct epitem" */
	struct list_head llink;

	/* The "base" pointer is set to the container "struct epitem" */
	struct epitem *base;

	/*
	 * Wait queue item that will be linked to the target file wait
	 * queue head.
	 */
	wait_queue_entry_t wait;

	/* The wait queue head that linked the "wait" wait queue item */
	wait_queue_head_t *whead;
}

struct ep_pqueue {
	poll_table pt;
	struct epitem *epi;
}


static void epi_rcu_free(struct rcu_head *head)
{
	struct epitem *epi = container_of(head, struct epitem, rcu);
	kmem_cache_free(epi_cache, epi);
}


static inline void ep_set_ffd(struct epoll_filefd *ffd,
			      struct file *file, int fd)
{
	ffd->file = file;
	ffd->fd = fd;
}


static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
			       void *priv)
{
	struct epitem *epi, *tmp;
	poll_table pt;
	int depth = *(int *)priv;

	init_poll_funcptr(&pt, NULL);
	depth++;

	list_for_each_entry_safe(epi, tmp, head, rdllink) {
		if (ep_item_poll(epi, &pt, depth)) {
			return EPOLLIN | EPOLLRDNORM;
		} else {
			/*
			 * Item has been dropped into the ready list by the poll
			 * callback, but it's not actually ready, as far as
			 * caller requested events goes. We can remove it here.
			 */
			__pm_relax(ep_wakeup_source(epi));
			list_del_init(&epi->rdllink);
		}
	}

	return 0;
}


static __poll_t ep_eventpoll_poll(struct file *file, poll_table *wait)
{
	struct eventpoll *ep = file->private_data;
	int depth = 0;

	/* Insert inside our poll wait queue */
	poll_wait(file, &ep->poll_wait, wait);

	/*
	 * Proceed to find out if wanted events are really available inside
	 * the ready list.
	 */
	return ep_scan_ready_list(ep, ep_read_events_proc,
				  &depth, depth, false);
}


static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
				 poll_table *pt)
{
	struct epitem *epi = ep_item_from_epqueue(pt);
	struct eppoll_entry *pwq;

	if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL))) {
		init_waitqueue_func_entry(&pwq->wait, ep_poll_callback);
		pwq->whead = whead;
		pwq->base = epi;
		if (epi->event.events & EPOLLEXCLUSIVE)
			add_wait_queue_exclusive(whead, &pwq->wait);
		else
			add_wait_queue(whead, &pwq->wait);
		list_add_tail(&pwq->llink, &epi->pwqlist);
		epi->nwait++;
	} else {
		/* We have to signal that an error occurred */
		epi->nwait = -1;
	}
}


static inline struct timespec64 ep_set_mstimeout(long ms)
{
	struct timespec64 now, ts = {
		.tv_sec = ms / MSEC_PER_SEC,
		.tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC),
	};

	ktime_get_ts64(&now);
	return timespec64_add_safe(now, ts);
}


static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
{
	struct eventpoll *ep;
	unsigned int napi_id;
	struct socket *sock;
	struct sock *sk;
	int err;

	if (!net_busy_loop_on())
		return;

	sock = sock_from_file(epi->ffd.file, &err);
	if (!sock)
		return;

	sk = sock->sk;
	if (!sk)
		return;

	napi_id = READ_ONCE(sk->sk_napi_id);
	ep = epi->ep;

	/* Non-NAPI IDs can be rejected
	 *	or
	 * Nothing to do if we already have this ID
	 */
	if (napi_id < MIN_NAPI_ID || napi_id == ep->napi_id)
		return;

	/* record NAPI ID for use in next busy poll */
	ep->napi_id = napi_id;
}


static inline bool chain_epi_lockless(struct epitem *epi)
{
	struct eventpoll *ep = epi->ep;

	/* Fast preliminary check */
	if (epi->next != EP_UNACTIVE_PTR)
		return false;

	/* Check that the same epi has not been just chained from another CPU */
	if (cmpxchg(&epi->next, EP_UNACTIVE_PTR, NULL) != EP_UNACTIVE_PTR)
		return false;

	/* Atomically exchange tail */
	epi->next = xchg(&ep->ovflist, epi);

	return true;
}


static int do_epoll_create(int flags)
{
	int error, fd;
	struct eventpoll *ep = NULL;
	struct file *file;

	/* Check the EPOLL_* constant for consistency.  */
	BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);

	if (flags & ~EPOLL_CLOEXEC)
		return -EINVAL;
	/*
	 * Create the internal data structure ("struct eventpoll").
	 */
	error = ep_alloc(&ep);
	if (error < 0)
		return error;
	/*
	 * Creates all the items needed to setup an eventpoll file. That is,
	 * a file structure and a free file descriptor.
	 */
	fd = get_unused_fd_flags(O_RDWR | (flags & O_CLOEXEC));
	if (fd < 0) {
		error = fd;
		goto out_free_ep;
	}
	file = anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep,
				 O_RDWR | (flags & O_CLOEXEC));
	if (IS_ERR(file)) {
		error = PTR_ERR(file);
		goto out_free_fd;
	}
	ep->file = file;
	fd_install(fd, file);
	return fd;

out_free_fd:
	put_unused_fd(fd);
out_free_ep:
	ep_free(ep);
	return error;
}


static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep)
{
	if (ep->napi_id)
		ep->napi_id = 0;
}


static inline struct wakeup_source *ep_wakeup_source(struct epitem *epi)
{
	return rcu_dereference_check(epi->ws, lockdep_is_held(&epi->ep->mtx));
}


SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
		struct epoll_event __user *, event)
{
	struct epoll_event epds;

	if (ep_op_has_event(op) &&
	    copy_from_user(&epds, event, sizeof(struct epoll_event)))
		return -EFAULT;

	return do_epoll_ctl(epfd, op, fd, &epds, false);
}


static inline struct epitem *ep_item_from_epqueue(poll_table *p)
{
	return container_of(p, struct ep_pqueue, pt)->epi;
}


static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep)
{
}


read_yin_case(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin, int options,
              struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    struct lyxml_elem *sub, *next, root;
    struct lys_node_case *cs;
    struct lys_node *retval, *node = NULL;
    int c_ftrs = 0, c_ext = 0, ret;
    void *reallocated;

    /* init */
    memset(&root, 0, sizeof root);

    cs = calloc(1, sizeof *cs);
    LY_CHECK_ERR_RETURN(!cs, LOGMEM(ctx), NULL);
    cs->nodetype = LYS_CASE;
    cs->prev = (struct lys_node *)cs;
    retval = (struct lys_node *)cs;

    if (read_yin_common(module, parent, retval, LYEXT_PAR_NODE, yin,
            OPT_IDENT | OPT_MODULE | (!(options & LYS_PARSE_OPT_CFG_MASK) ? OPT_CFG_INHERIT : 0), unres)) {
        goto error;
    }

    LOGDBG(LY_LDGYIN, "parsing %s statement \"%s\"", yin->name, retval->name);

    /* insert the node into the schema tree */
    if (lys_node_addchild(parent, lys_main_module(module), retval, options)) {
        goto error;
    }

    /* process choice's specific children */
    LY_TREE_FOR_SAFE(yin->child, next, sub) {
        if (strcmp(sub->ns->value, LY_NSYIN)) {
            /* extension */
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ext, retval->ext_size, "extensions", "case", error);
            c_ext++;
        } else if (!strcmp(sub->name, "container") ||
                !strcmp(sub->name, "leaf-list") ||
                !strcmp(sub->name, "leaf") ||
                !strcmp(sub->name, "list") ||
                !strcmp(sub->name, "uses") ||
                !strcmp(sub->name, "choice") ||
                !strcmp(sub->name, "anyxml") ||
                !strcmp(sub->name, "anydata")) {

            lyxml_unlink_elem(ctx, sub, 2);
            lyxml_add_child(ctx, &root, sub);
        } else if (!strcmp(sub->name, "if-feature")) {
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ftrs, retval->iffeature_size, "if-features", "case", error);
            c_ftrs++;
        } else if (!strcmp(sub->name, "when")) {
            if (cs->when) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_LYS, retval, sub->name, yin->name);
                goto error;
            }

            cs->when = read_yin_when(module, sub, unres);
            if (!cs->when) {
                goto error;
            }

            lyxml_free(ctx, sub);
        } else {
            LOGVAL(ctx, LYE_INSTMT, LY_VLOG_LYS, retval, sub->name);
            goto error;
        }
    }

    if (c_ftrs) {
        cs->iffeature = calloc(c_ftrs, sizeof *cs->iffeature);
        LY_CHECK_ERR_GOTO(!cs->iffeature, LOGMEM(ctx), error);
    }
    if (c_ext) {
        /* some extensions may be already present from the substatements */
        reallocated = realloc(retval->ext, (c_ext + retval->ext_size) * sizeof *retval->ext);
        LY_CHECK_ERR_GOTO(!reallocated, LOGMEM(ctx), error);
        retval->ext = reallocated;

        /* init memory */
        memset(&retval->ext[retval->ext_size], 0, c_ext * sizeof *retval->ext);
    }

    LY_TREE_FOR_SAFE(yin->child, next, sub) {
        if (strcmp(sub->ns->value, LY_NSYIN)) {
            /* extension */
            ret = lyp_yin_fill_ext(retval, LYEXT_PAR_NODE, 0, 0, module, sub, &retval->ext, &retval->ext_size, unres);
            if (ret) {
                goto error;
            }
        } else {
            /* if-feature */
            ret = fill_yin_iffeature(retval, 0, sub, &cs->iffeature[cs->iffeature_size], unres);
            cs->iffeature_size++;
            if (ret) {
                goto error;
            }
        }
    }

    lyp_reduce_ext_list(&retval->ext, retval->ext_size, c_ext + retval->ext_size);

    /* last part - process data nodes */
    LY_TREE_FOR_SAFE(root.child, next, sub) {
        if (!strcmp(sub->name, "container")) {
            node = read_yin_container(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "leaf-list")) {
            node = read_yin_leaflist(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "leaf")) {
            node = read_yin_leaf(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "list")) {
            node = read_yin_list(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "choice")) {
            node = read_yin_choice(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "uses")) {
            node = read_yin_uses(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "anyxml")) {
            node = read_yin_anydata(module, retval, sub, LYS_ANYXML, options, unres);
        } else if (!strcmp(sub->name, "anydata")) {
            node = read_yin_anydata(module, retval, sub, LYS_ANYDATA, options, unres);
        }
        if (!node) {
            goto error;
        }

        lyxml_free(ctx, sub);
    }

    /* check XPath dependencies */
    if (!(ctx->models.flags & LY_CTX_TRUSTED) && cs->when) {
        if (options & LYS_PARSE_OPT_INGRP) {
            if (lyxp_node_check_syntax(retval)) {
                goto error;
            }
        } else {
            if (unres_schema_add_node(module, unres, retval, UNRES_XPATH, NULL) == -1) {
                goto error;
            }
        }
    }

    return retval;

error:
    while (root.child) {
        lyxml_free(ctx, root.child);
    }
    lys_node_free(ctx, retval, NULL, 0);

    return NULL;
}

yin parser BUGFIX invalid memory access

... in case there were some unresolved
extensions.
Fixes #1454
Fixes #1455

#define GETVAL(ctx, value, node, arg)                                                 \
    value = lyxml_get_attr(node, arg, NULL);                                     \
    if (!value) {                                                                \
        LOGVAL(ctx, LYE_MISSARG, LY_VLOG_NONE, NULL, arg, node->name);                \
        goto error;                                                              \
    }

#define YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, code)      \
    if ((counter) == LY_ARRAY_MAX(storage)) {                                    \
        LOGERR(ctx, LY_EINT, "Reached limit (%"PRIu64") for storing %s in %s statement.", \
               LY_ARRAY_MAX(storage), name, parent);                             \
        code;                                                                    \
    }

#define YIN_CHECK_ARRAY_OVERFLOW_RETURN(ctx, counter, storage, name, parent, retval)  \
    YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, return retval)

#define YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, counter, storage, name, parent, target)    \
    YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, goto target)

#define OPT_IDENT       0x01

#define OPT_CFG_INHERIT 0x04

#define OPT_MODULE      0x10

static int read_yin_common(struct lys_module *, struct lys_node *, void *, LYEXT_PAR, struct lyxml_elem *, int,
                           struct unres_schema *);

static struct lys_node *read_yin_choice(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                        int options, struct unres_schema *unres);

static struct lys_node *read_yin_case(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_anydata(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                         LYS_NODE type, int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_container(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                           int options, struct unres_schema *unres);

static struct lys_node *read_yin_leaf(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_leaflist(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                          int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_list(struct lys_module *module,struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_uses(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_grouping(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                          int options, struct unres_schema *unres);

static struct lys_node *read_yin_rpc_action(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                            int options, struct unres_schema *unres);

static struct lys_node *read_yin_notif(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                       int options, struct unres_schema *unres);

static struct lys_when *read_yin_when(struct lys_module *module, struct lyxml_elem *yin, struct unres_schema *unres);


yin_read_submodule(struct lys_module *module, const char *data, struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    struct lyxml_elem *yin;
    struct lys_submodule *submodule = NULL;
    const char *value;

    yin = lyxml_parse_mem(ctx, data, LYXML_PARSE_NOMIXEDCONTENT);
    if (!yin) {
        return NULL;
    }

    /* check root element */
    if (!yin->name || strcmp(yin->name, "submodule")) {
        LOGVAL(ctx, LYE_INSTMT, LY_VLOG_NONE, NULL, yin->name);
        goto error;
    }

    GETVAL(ctx, value, yin, "name");
    if (lyp_check_identifier(ctx, value, LY_IDENT_NAME, NULL, NULL)) {
        goto error;
    }

    submodule = calloc(1, sizeof *submodule);
    LY_CHECK_ERR_GOTO(!submodule, LOGMEM(ctx), error);

    submodule->ctx = ctx;
    submodule->name = lydict_insert(ctx, value, strlen(value));
    submodule->type = 1;
    submodule->implemented = module->implemented;
    submodule->belongsto = module;

    /* add into the list of processed modules */
    if (lyp_check_circmod_add((struct lys_module *)submodule)) {
        goto error;
    }

    LOGVRB("Reading submodule \"%s\".", submodule->name);
    /* module cannot be changed in this case and 1 cannot be returned */
    if (read_sub_module(module, submodule, yin, unres)) {
        goto error;
    }

    lyp_sort_revisions((struct lys_module *)submodule);

    /* cleanup */
    lyxml_free(ctx, yin);
    lyp_check_circmod_pop(ctx);

    LOGVRB("Submodule \"%s\" successfully parsed.", submodule->name);
    return submodule;

error:
    /* cleanup */
    lyxml_free(ctx, yin);
    if (!submodule) {
        LOGERR(ctx, ly_errno, "Submodule parsing failed.");
        return NULL;
    }

    LOGERR(ctx, ly_errno, "Submodule \"%s\" parsing failed.", submodule->name);

    unres_schema_free((struct lys_module *)submodule, &unres, 0);
    lyp_check_circmod_pop(ctx);
    lys_sub_module_remove_devs_augs((struct lys_module *)submodule);
    lys_submodule_module_data_free(submodule);
    lys_submodule_free(submodule, NULL);
    return NULL;
}

#define GETVAL(ctx, value, node, arg)                                                 \
    value = lyxml_get_attr(node, arg, NULL);                                     \
    if (!value) {                                                                \
        LOGVAL(ctx, LYE_MISSARG, LY_VLOG_NONE, NULL, arg, node->name);                \
        goto error;                                                              \
    }

#define YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, code)      \
    if ((counter) == LY_ARRAY_MAX(storage)) {                                    \
        LOGERR(ctx, LY_EINT, "Reached limit (%"PRIu64") for storing %s in %s statement.", \
               LY_ARRAY_MAX(storage), name, parent);                             \
        code;                                                                    \
    }

#define YIN_CHECK_ARRAY_OVERFLOW_RETURN(ctx, counter, storage, name, parent, retval)  \
    YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, return retval)

#define YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, counter, storage, name, parent, target)    \
    YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, goto target)

static int read_yin_common(struct lys_module *, struct lys_node *, void *, LYEXT_PAR, struct lyxml_elem *, int,
                           struct unres_schema *);

static struct lys_node *read_yin_choice(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                        int options, struct unres_schema *unres);

static struct lys_node *read_yin_case(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_anydata(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                         LYS_NODE type, int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_container(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                           int options, struct unres_schema *unres);

static struct lys_node *read_yin_leaf(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_leaflist(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                          int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_list(struct lys_module *module,struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_uses(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_grouping(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                          int options, struct unres_schema *unres);

static struct lys_node *read_yin_rpc_action(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                            int options, struct unres_schema *unres);

static struct lys_node *read_yin_notif(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                       int options, struct unres_schema *unres);

static struct lys_when *read_yin_when(struct lys_module *module, struct lyxml_elem *yin, struct unres_schema *unres);


fill_yin_revision(struct lys_module *module, struct lyxml_elem *yin, struct lys_revision *rev,
                  struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    struct lyxml_elem *next, *child;
    const char *value;

    GETVAL(ctx, value, yin, "date");
    if (lyp_check_date(ctx, value)) {
        goto error;
    }
    memcpy(rev->date, value, LY_REV_SIZE - 1);

    LY_TREE_FOR_SAFE(yin->child, next, child) {
        if (!child->ns) {
            /* garbage */
            continue;
        } else if (strcmp(child->ns->value, LY_NSYIN)) {
            /* possible extension instance */
            if (lyp_yin_parse_subnode_ext(module, rev, LYEXT_PAR_REVISION,
                                          child, LYEXT_SUBSTMT_SELF, 0, unres)) {
                goto error;
            }
        } else if (!strcmp(child->name, "description")) {
            if (rev->dsc) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, child->name, yin->name);
                goto error;
            }
            if (lyp_yin_parse_subnode_ext(module, rev, LYEXT_PAR_REVISION,
                                          child, LYEXT_SUBSTMT_DESCRIPTION, 0, unres)) {
                goto error;
            }
            rev->dsc = read_yin_subnode(ctx, child, "text");
            if (!rev->dsc) {
                goto error;
            }
        } else if (!strcmp(child->name, "reference")) {
            if (rev->ref) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, child->name, yin->name);
                goto error;
            }
            if (lyp_yin_parse_subnode_ext(module, rev, LYEXT_PAR_REVISION,
                                          child, LYEXT_SUBSTMT_REFERENCE, 0, unres)) {
                goto error;
            }
            rev->ref = read_yin_subnode(ctx, child, "text");
            if (!rev->ref) {
                goto error;
            }
        } else {
            LOGVAL(ctx, LYE_INSTMT, LY_VLOG_NONE, NULL, child->name);
            goto error;
        }
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}


lyp_yin_parse_subnode_ext(struct lys_module *mod, void *elem, LYEXT_PAR elem_type,
                     struct lyxml_elem *yin, LYEXT_SUBSTMT type, uint8_t i, struct unres_schema *unres)
{
    void *reallocated;
    struct lyxml_elem *next, *child;
    int r;
    struct lys_ext_instance ***ext;
    uint8_t *ext_size;
    const char *statement;

    r = lyp_get_ext_list(mod->ctx, elem, elem_type, &ext, &ext_size, &statement);
    LY_CHECK_RETURN(r, EXIT_FAILURE);

    if (type == LYEXT_SUBSTMT_SELF) {
        /* parse for the statement self, not for the substatement */
        child = yin;
        next = NULL;
        goto parseext;
    }

    LY_TREE_FOR_SAFE(yin->child, next, child) {
        if (!child->ns) {
            LOGVAL(mod->ctx, LYE_SPEC, LY_VLOG_NONE, NULL, "Extension instance \"%s\" is missing namespace.", child->name);
            return EXIT_FAILURE;
        }
        if (!strcmp(child->ns->value, LY_NSYIN)) {
            /* skip the regular YIN nodes */
            continue;
        }

        /* parse it as extension */
parseext:

        YIN_CHECK_ARRAY_OVERFLOW_RETURN(mod->ctx, *ext_size, *ext_size, "extension", statement, EXIT_FAILURE);
        /* first, allocate a space for the extension instance in the parent elem */
        reallocated = realloc(*ext, (1 + (*ext_size)) * sizeof **ext);
        LY_CHECK_ERR_RETURN(!reallocated, LOGMEM(mod->ctx), EXIT_FAILURE);
        (*ext) = reallocated;

        /* init memory */
        (*ext)[(*ext_size)] = NULL;

        /* parse YIN data */
        r = lyp_yin_fill_ext(elem, elem_type, type, i, mod, child, ext, ext_size, unres);
        if (r) {
            return EXIT_FAILURE;
        }

        lyp_reduce_ext_list(ext, *ext_size, 1 + (*ext_size));

        /* done - do not free the child, it is unlinked in lyp_yin_fill_ext */
    }

    return EXIT_SUCCESS;
}


lyp_yin_fill_ext(void *parent, LYEXT_PAR parent_type, LYEXT_SUBSTMT substmt, uint8_t substmt_index,
             struct lys_module *module, struct lyxml_elem *yin, struct lys_ext_instance ***ext,
             uint8_t *ext_size, struct unres_schema *unres)
{
    struct unres_ext *info;
    int rc;

    info = malloc(sizeof *info);
    LY_CHECK_ERR_RETURN(!info, LOGMEM(module->ctx), EXIT_FAILURE);
    lyxml_unlink(module->ctx, yin);
    info->data.yin = yin;
    info->datatype = LYS_IN_YIN;
    info->parent = parent;
    info->mod = module;
    info->parent_type = parent_type;
    info->substmt = substmt;
    info->substmt_index = substmt_index;
    info->ext_index = *ext_size;

    rc = unres_schema_add_node(module, unres, ext, UNRES_EXT, (struct lys_node *)info);
    if (!rc && !(*ext)[*ext_size]) {
        /* extension instance is skipped */
    } else {
        ++(*ext_size);
    }

    return rc == -1 ? EXIT_FAILURE : EXIT_SUCCESS;
}


read_yin_subnode(struct ly_ctx *ctx, struct lyxml_elem *node, const char *name)
{
    int len;

    /* there should be <text> child */
    if (!node->child || !node->child->name || strcmp(node->child->name, name)) {
        LOGERR(ctx, LY_EVALID, "Expected \"%s\" element in \"%s\" element.", name, node->name);
        LOGVAL(ctx, LYE_INARG, LY_VLOG_NONE, NULL, name, node->name);
        return NULL;
    } else if (node->child->content) {
        len = strlen(node->child->content);
        return lydict_insert(ctx, node->child->content, len);
    } else {
        return lydict_insert(ctx, "", 0);
    }
}


yin_parse_extcomplex_flag(struct lys_module *mod, struct lyxml_elem *node,
                          struct lys_ext_instance_complex *ext, LY_STMT stmt,
                          const char *val1_str, const char *val2_str, uint16_t mask,
                          uint16_t val1, uint16_t val2, struct unres_schema *unres)
{
    uint16_t *val;
    const char *str;

    val = yin_getplace_for_extcomplex_flags(node, ext, stmt, mask);
    if (!val) {
        return EXIT_FAILURE;
    }

    str = lyxml_get_attr(node, "value", NULL);
    if (!str) {
        LOGVAL(mod->ctx, LYE_MISSARG, LY_VLOG_NONE, NULL, "value", node->name);
    } else if (!strcmp(val1_str, str)) {
        *val = *val | val1;
    } else if (!strcmp(val2_str, str)) {
        *val = *val | val2;
    } else {
        /* unknown value */
        LOGVAL(mod->ctx, LYE_INARG, LY_VLOG_NONE, NULL, str, node->name);
        return EXIT_FAILURE;
    }
    if (lyp_yin_parse_subnode_ext(mod, ext, LYEXT_PAR_EXTINST, node, (LYEXT_SUBSTMT)stmt, 0, unres)) {
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}


yin_getplace_for_extcomplex_struct(struct lyxml_elem *node, struct lys_ext_instance_complex *ext, LY_STMT stmt)
{
    int c;
    void **data, ***p = NULL;
    void *reallocated;
    struct lyext_substmt *info;

    data = lys_ext_complex_get_substmt(stmt, ext, &info);
    if (!data) {
        LOGVAL(ext->module->ctx, LYE_INCHILDSTMT, LY_VLOG_NONE, NULL, node->name, node->parent->name);
        return NULL;
    }
    if (info->cardinality < LY_STMT_CARD_SOME && *data) {
        LOGVAL(ext->module->ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, node->name, node->parent->name);
        return NULL;
    }

    c = 0;
    if (info->cardinality >= LY_STMT_CARD_SOME) {
        /* there can be multiple instances, so instead of pointer to array,
         * we have in data pointer to pointer to array */
        p = (void ***)data;
        data = *p;
        if (!data) {
            /* allocate initial array */
            *p = data = malloc(2 * sizeof(void *));
            LY_CHECK_ERR_RETURN(!data, LOGMEM(ext->module->ctx), NULL);
        } else {
            for (c = 0; *data; data++, c++);
        }
    }

    if (p) {
        /* enlarge the array */
        reallocated = realloc(*p, (c + 2) * sizeof(void *));
        LY_CHECK_ERR_RETURN(!reallocated, LOGMEM(ext->module->ctx), NULL);
        *p = reallocated;
        data = *p;
        data[c + 1] = NULL;
    }

    return &data[c];
}


yin_parse_extcomplex_bool(struct lys_module *mod, struct lyxml_elem *node,
                          struct lys_ext_instance_complex *ext, LY_STMT stmt,
                          const char *true_val, const char *false_val, struct unres_schema *unres)
{
    uint8_t *val;
    const char *str;
    struct lyext_substmt *info;

    val = lys_ext_complex_get_substmt(stmt, ext, &info);
    if (!val) {
        LOGVAL(mod->ctx, LYE_INCHILDSTMT, LY_VLOG_NONE, NULL, node->name, node->parent->name);
        return EXIT_FAILURE;
    }
    if (*val) {
        LOGVAL(mod->ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, node->name, node->parent->name);
        return EXIT_FAILURE;
    }

    if (lyp_yin_parse_subnode_ext(mod, ext, LYEXT_PAR_EXTINST, node, (LYEXT_SUBSTMT)stmt, 0, unres)) {
        return EXIT_FAILURE;
    }

    str = lyxml_get_attr(node, "value", NULL);
    if (!str) {
        LOGVAL(mod->ctx, LYE_MISSARG, LY_VLOG_NONE, NULL, "value", node->name);
    } else if (true_val && !strcmp(true_val, str)) {
        /* true value */
        *val = 1;
    } else if (false_val && !strcmp(false_val, str)) {
        /* false value */
        *val = 2;
    } else {
        /* unknown value */
        LOGVAL(mod->ctx, LYE_INARG, LY_VLOG_NONE, NULL, str, node->name);
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}


fill_yin_must(struct lys_module *module, struct lyxml_elem *yin, struct lys_restr *must, struct unres_schema *unres)
{
    int ret = EXIT_FAILURE;
    const char *value;

    must->expr = NULL;
    GETVAL(module->ctx, value, yin, "condition");
    must->expr = transform_schema2json(module, value);
    if (!must->expr) {
        goto error;
    }

    ret = read_restr_substmt(module, must, yin, unres);

error:
    if (ret) {
        lydict_remove(module->ctx, must->expr);
        must->expr = NULL;
    }
    return ret;
}


read_yin_rpc_action(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                    int options, struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    struct lyxml_elem *sub, *next, root;
    struct lys_node *node = NULL;
    struct lys_node *retval;
    struct lys_node_rpc_action *rpc;
    int r;
    int c_tpdf = 0, c_ftrs = 0, c_input = 0, c_output = 0, c_ext = 0;
    void *reallocated;

    if (!strcmp(yin->name, "action") && (module->version < 2)) {
        LOGVAL(ctx, LYE_INSTMT, LY_VLOG_LYS, parent, "action");
        return NULL;
    }

    /* init */
    memset(&root, 0, sizeof root);

    rpc = calloc(1, sizeof *rpc);
    LY_CHECK_ERR_RETURN(!rpc, LOGMEM(ctx), NULL);

    rpc->nodetype = (!strcmp(yin->name, "rpc") ? LYS_RPC : LYS_ACTION);
    rpc->prev = (struct lys_node *)rpc;
    retval = (struct lys_node *)rpc;

    if (read_yin_common(module, parent, retval, LYEXT_PAR_NODE, yin, OPT_IDENT | OPT_MODULE, unres)) {
        goto error;
    }

    LOGDBG(LY_LDGYIN, "parsing %s statement \"%s\"", yin->name, retval->name);

    /* insert the node into the schema tree */
    if (lys_node_addchild(parent, lys_main_module(module), retval, options)) {
        goto error;
    }

    /* process rpc's specific children */
    LY_TREE_FOR_SAFE(yin->child, next, sub) {
        if (strcmp(sub->ns->value, LY_NSYIN)) {
            /* extension */
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ext, retval->ext_size, "extensions",
                                          rpc->nodetype == LYS_RPC ? "rpc" : "action", error);
            c_ext++;
            continue;
        } else if (!strcmp(sub->name, "input")) {
            if (c_input) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_LYS, retval, sub->name, yin->name);
                goto error;
            }
            c_input++;
            lyxml_unlink_elem(ctx, sub, 2);
            lyxml_add_child(ctx, &root, sub);
        } else if (!strcmp(sub->name, "output")) {
            if (c_output) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_LYS, retval, sub->name, yin->name);
                goto error;
            }
            c_output++;
            lyxml_unlink_elem(ctx, sub, 2);
            lyxml_add_child(ctx, &root, sub);

            /* data statements */
        } else if (!strcmp(sub->name, "grouping")) {
            lyxml_unlink_elem(ctx, sub, 2);
            lyxml_add_child(ctx, &root, sub);

            /* array counters */
        } else if (!strcmp(sub->name, "typedef")) {
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_tpdf, rpc->tpdf_size, "typedefs",
                                          rpc->nodetype == LYS_RPC ? "rpc" : "action", error);
            c_tpdf++;
        } else if (!strcmp(sub->name, "if-feature")) {
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ftrs, retval->iffeature_size, "if-features",
                                          rpc->nodetype == LYS_RPC ? "rpc" : "action", error);
            c_ftrs++;
        } else {
            LOGVAL(ctx, LYE_INSTMT, LY_VLOG_LYS, retval, sub->name);
            goto error;
        }
    }

    /* middle part - process nodes with cardinality of 0..n except the data nodes */
    if (c_tpdf) {
        rpc->tpdf = calloc(c_tpdf, sizeof *rpc->tpdf);
        LY_CHECK_ERR_GOTO(!rpc->tpdf, LOGMEM(ctx), error);
    }
    if (c_ftrs) {
        rpc->iffeature = calloc(c_ftrs, sizeof *rpc->iffeature);
        LY_CHECK_ERR_GOTO(!rpc->iffeature, LOGMEM(ctx), error);
    }
    if (c_ext) {
        /* some extensions may be already present from the substatements */
        reallocated = realloc(retval->ext, (c_ext + retval->ext_size) * sizeof *retval->ext);
        LY_CHECK_ERR_GOTO(!reallocated, LOGMEM(ctx), error);
        retval->ext = reallocated;

        /* init memory */
        memset(&retval->ext[retval->ext_size], 0, c_ext * sizeof *retval->ext);
    }

    LY_TREE_FOR_SAFE(yin->child, next, sub) {
        if (strcmp(sub->ns->value, LY_NSYIN)) {
            /* extension */
            r = lyp_yin_fill_ext(retval, LYEXT_PAR_NODE, 0, 0, module, sub, &retval->ext, &retval->ext_size, unres);
            if (r) {
                goto error;
            }
        } else if (!strcmp(sub->name, "typedef")) {
            r = fill_yin_typedef(module, retval, sub, &rpc->tpdf[rpc->tpdf_size], unres);
            rpc->tpdf_size++;
            if (r) {
                goto error;
            }
        } else if (!strcmp(sub->name, "if-feature")) {
            r = fill_yin_iffeature(retval, 0, sub, &rpc->iffeature[rpc->iffeature_size], unres);
            rpc->iffeature_size++;
            if (r) {
                goto error;
            }
        }
    }

    lyp_reduce_ext_list(&retval->ext, retval->ext_size, c_ext + retval->ext_size);

    /* last part - process data nodes */
    LY_TREE_FOR_SAFE(root.child, next, sub) {
        if (!strcmp(sub->name, "grouping")) {
            node = read_yin_grouping(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "input") || !strcmp(sub->name, "output")) {
            node = read_yin_input_output(module, retval, sub, options, unres);
        }
        if (!node) {
            goto error;
        }

        lyxml_free(ctx, sub);
    }

    return retval;

error:
    lys_node_free(ctx, retval, NULL, 0);
    while (root.child) {
        lyxml_free(ctx, root.child);
    }
    return NULL;
}

#define GETVAL(ctx, value, node, arg)                                                 \
    value = lyxml_get_attr(node, arg, NULL);                                     \
    if (!value) {                                                                \
        LOGVAL(ctx, LYE_MISSARG, LY_VLOG_NONE, NULL, arg, node->name);                \
        goto error;                                                              \
    }

#define YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, code)      \
    if ((counter) == LY_ARRAY_MAX(storage)) {                                    \
        LOGERR(ctx, LY_EINT, "Reached limit (%"PRIu64") for storing %s in %s statement.", \
               LY_ARRAY_MAX(storage), name, parent);                             \
        code;                                                                    \
    }

#define YIN_CHECK_ARRAY_OVERFLOW_RETURN(ctx, counter, storage, name, parent, retval)  \
    YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, return retval)

#define YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, counter, storage, name, parent, target)    \
    YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, counter, storage, name, parent, goto target)

#define OPT_IDENT       0x01

#define OPT_MODULE      0x10

static int read_yin_common(struct lys_module *, struct lys_node *, void *, LYEXT_PAR, struct lyxml_elem *, int,
                           struct unres_schema *);

static struct lys_node *read_yin_choice(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                        int options, struct unres_schema *unres);

static struct lys_node *read_yin_case(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_anydata(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                         LYS_NODE type, int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_container(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                           int options, struct unres_schema *unres);

static struct lys_node *read_yin_leaf(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_leaflist(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                          int valid_config, struct unres_schema *unres);

static struct lys_node *read_yin_list(struct lys_module *module,struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_uses(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                      int options, struct unres_schema *unres);

static struct lys_node *read_yin_grouping(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                          int options, struct unres_schema *unres);

static struct lys_node *read_yin_rpc_action(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                            int options, struct unres_schema *unres);

static struct lys_node *read_yin_notif(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
                                       int options, struct unres_schema *unres);

static struct lys_when *read_yin_when(struct lys_module *module, struct lyxml_elem *yin, struct unres_schema *unres);