Merge tag 'vfs-6.13-rc7.fixes.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:
 "afs:

   - Fix the maximum cell name length

   - Fix merge preference rule failure condition

  fuse:

   - Fix fuse_get_user_pages() so it doesn't risk misleading the caller
     to think pages have been allocated when they actually haven't

   - Fix direct-io folio offset and length calculation

  netfs:

   - Fix async direct-io handling

   - Fix read-retry for filesystems that don't provide a
     ->prepare_read() method

  vfs:

   - Prevent truncating 64-bit offsets to 32-bits in iomap

   - Fix memory barrier interactions when polling

   - Remove MNT_ONRB to fix concurrent modification of @mnt->mnt_flags
     leading to MNT_ONRB to not be raised and invalid access to a list
     member"

* tag 'vfs-6.13-rc7.fixes.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  poll: kill poll_does_not_wait()
  sock_poll_wait: kill the no longer necessary barrier after poll_wait()
  io_uring_poll: kill the no longer necessary barrier after poll_wait()
  poll_wait: kill the obsolete wait_address check
  poll_wait: add mb() to fix theoretical race between waitqueue_active() and .poll()
  afs: Fix merge preference rule failure condition
  netfs: Fix read-retry for fs with no ->prepare_read()
  netfs: Fix kernel async DIO
  fs: kill MNT_ONRB
  iomap: avoid avoid truncating 64-bit offset to 32 bits
  afs: Fix the maximum cell name length
  fuse: Set *nbytesp=0 in fuse_get_user_pages on allocation failure
  fuse: fix direct io folio offset and length calculation

3 files changed, 20 insertions, 26 deletions

diff --git a/include/linux/mount.h b/include/linux/mount.h
index c34c18b4e8f3..04213d8ef837 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -50,7 +50,7 @@ struct path;
 #define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
 
 #define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
-			    MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED | MNT_ONRB)
+			    MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
 
 #define MNT_INTERNAL	0x4000
 
@@ -64,7 +64,6 @@ struct path;
 #define MNT_SYNC_UMOUNT		0x2000000
 #define MNT_MARKED		0x4000000
 #define MNT_UMOUNT		0x8000000
-#define MNT_ONRB		0x10000000
 
 struct vfsmount {
 	struct dentry *mnt_root;	/* root of the mounted tree */
diff --git a/include/linux/poll.h b/include/linux/poll.h
index d1ea4f3714a8..12bb18e8b978 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -25,14 +25,14 @@
 
 struct poll_table_struct;
 
-/* 
+/*
  * structures and helpers for f_op->poll implementations
  */
 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.
- */
-static inline bool poll_does_not_wait(const poll_table *p)
-{
-	return p == NULL || p->_qproc == NULL;
+		/*
+		 * 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.
+		 */
+		smp_mb();
+	}
 }
 
 /*
diff --git a/include/net/sock.h b/include/net/sock.h
index c383126f691d..691ca7695d1d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -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.
-		 *
-		 * This memory barrier is paired in the wq_has_sleeper.
-		 */
-		smp_mb();
-	}
+	/* 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.
+	 */
+	poll_wait(filp, &sock->wq.wait, p);
 }
 
 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)