Unverified Commit 1623bc27 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge branch 'vfs-6.14.poll' into vfs.fixes 



Bring in the fixes for __pollwait() and waitqueue_active() interactions.

Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 17a4fde8 67cd2e23

include/linux/poll.h

+12 −14
Original line number Diff line number Diff line
@@ -31,8 +31,8 @@ struct poll_table_struct; 
typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);



/*

 * Do not touch the structure directly, use the access functions

 * poll_does_not_wait() and poll_requested_events() instead.

 * Do not touch the structure directly, use the access function

 * poll_requested_events() instead.

 */

typedef struct poll_table_struct {

	poll_queue_proc _qproc;
@@ -41,18 +41,16 @@ typedef struct poll_table_struct { 


static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)

{

	if (p && p->_qproc && wait_address)

	if (p && p->_qproc) {

		p->_qproc(filp, wait_address, p);

}



		/*

 * Return true if it is guaranteed that poll will not wait. This is the case

 * if the poll() of another file descriptor in the set got an event, so there

 * is no need for waiting.

		 * This memory barrier is paired in the wq_has_sleeper().

		 * See the comment above prepare_to_wait(), we need to

		 * ensure that subsequent tests in this thread can't be

		 * reordered with __add_wait_queue() in _qproc() paths.

		 */

static inline bool poll_does_not_wait(const poll_table *p)

{

	return p == NULL || p->_qproc == NULL;

		smp_mb();

	}

}



/*

include/net/sock.h

+7 −10
Original line number Diff line number Diff line
@@ -2297,7 +2297,7 @@ static inline bool skwq_has_sleeper(struct socket_wq *wq) 
}



/**

 * sock_poll_wait - place memory barrier behind the poll_wait call.

 * sock_poll_wait - wrapper for the poll_wait call.

 * @filp:           file

 * @sock:           socket to wait on

 * @p:              poll_table
@@ -2307,15 +2307,12 @@ static inline bool skwq_has_sleeper(struct socket_wq *wq) 
static inline void sock_poll_wait(struct file *filp, struct socket *sock,

				  poll_table *p)

{

	if (!poll_does_not_wait(p)) {

		poll_wait(filp, &sock->wq.wait, p);

		/* We need to be sure we are in sync with the

		 * socket flags modification.

	/* Provides a barrier we need to be sure we are in sync

	 * with the socket flags modification.

	 *

	 * This memory barrier is paired in the wq_has_sleeper.

	 */

		smp_mb();

	}

	poll_wait(filp, &sock->wq.wait, p);

}



static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)

io_uring/io_uring.c

+4 −5
Original line number Diff line number Diff line
@@ -2813,13 +2813,12 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait) 


	if (unlikely(!ctx->poll_activated))

		io_activate_pollwq(ctx);



	poll_wait(file, &ctx->poll_wq, wait);

	/*

	 * synchronizes with barrier from wq_has_sleeper call in

	 * io_commit_cqring

	 * provides mb() which pairs with barrier from wq_has_sleeper

	 * call in io_commit_cqring

	 */

	smp_rmb();

	poll_wait(file, &ctx->poll_wq, wait);



	if (!io_sqring_full(ctx))

		mask |= EPOLLOUT | EPOLLWRNORM;