Commit db502f8a authored by Al Viro's avatar Al Viro
Browse files

ep_scan_ready_list(): prepare to splitup 



take the stuff done before and after the callback into separate helpers

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent bde03c4c

fs/eventpoll.c

+36 −27
Original line number Diff line number Diff line
@@ -561,28 +561,10 @@ static inline void ep_pm_stay_awake_rcu(struct epitem *epi) 
	rcu_read_unlock();

}



/**

 * ep_scan_ready_list - Scans the ready list in a way that makes possible for

 *                      the scan code, to call f_op->poll(). Also allows for

 *                      O(NumReady) performance.

 *

 * @ep: Pointer to the epoll private data structure.

 * @sproc: Pointer to the scan callback.

 * @priv: Private opaque data passed to the @sproc callback.

 * @depth: The current depth of recursive f_op->poll calls.

 * @ep_locked: caller already holds ep->mtx

 *

 * Returns: The same integer error code returned by the @sproc callback.

 */

static __poll_t ep_scan_ready_list(struct eventpoll *ep,

			      __poll_t (*sproc)(struct eventpoll *,

					   struct list_head *, void *),

			      void *priv, int depth, bool ep_locked)

static void ep_start_scan(struct eventpoll *ep,

			  int depth, bool ep_locked,

			  struct list_head *txlist)

{

	__poll_t res;

	struct epitem *epi, *nepi;

	LIST_HEAD(txlist);



	lockdep_assert_irqs_enabled();



	/*
@@ -602,14 +584,16 @@ static __poll_t ep_scan_ready_list(struct eventpoll *ep, 
	 * in a lockless way.

	 */

	write_lock_irq(&ep->lock);

	list_splice_init(&ep->rdllist, &txlist);

	list_splice_init(&ep->rdllist, txlist);

	WRITE_ONCE(ep->ovflist, NULL);

	write_unlock_irq(&ep->lock);

}



	/*

	 * Now call the callback function.

	 */

	res = (*sproc)(ep, &txlist, priv);

static void ep_done_scan(struct eventpoll *ep,

			 int depth, bool ep_locked,

			 struct list_head *txlist)

{

	struct epitem *epi, *nepi;



	write_lock_irq(&ep->lock);

	/*
@@ -644,13 +628,38 @@ static __poll_t ep_scan_ready_list(struct eventpoll *ep, 
	/*

	 * Quickly re-inject items left on "txlist".

	 */

	list_splice(&txlist, &ep->rdllist);

	list_splice(txlist, &ep->rdllist);

	__pm_relax(ep->ws);

	write_unlock_irq(&ep->lock);



	if (!ep_locked)

		mutex_unlock(&ep->mtx);

}



/**

 * ep_scan_ready_list - Scans the ready list in a way that makes possible for

 *                      the scan code, to call f_op->poll(). Also allows for

 *                      O(NumReady) performance.

 *

 * @ep: Pointer to the epoll private data structure.

 * @sproc: Pointer to the scan callback.

 * @priv: Private opaque data passed to the @sproc callback.

 * @depth: The current depth of recursive f_op->poll calls.

 * @ep_locked: caller already holds ep->mtx

 *

 * Returns: The same integer error code returned by the @sproc callback.

 */

static __poll_t ep_scan_ready_list(struct eventpoll *ep,

			      __poll_t (*sproc)(struct eventpoll *,

					   struct list_head *, void *),

			      void *priv, int depth, bool ep_locked)

{

	__poll_t res;

	LIST_HEAD(txlist);



	ep_start_scan(ep, depth, ep_locked, &txlist);

	res = (*sproc)(ep, &txlist, priv);

	ep_done_scan(ep, depth, ep_locked, &txlist);

	return res;

}