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| author |   Christoph Hellwig <hch@lst.de> | 2018-01-09 15:29:24 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2018-05-26 09:16:44 +0200 |
| commit | 3deb642f0de4c14f37437dd247f9c77839f043f8 (patch) | |
| tree | 56f6867ac66e6fa881295a6c9af52349471374e4 /Documentation/filesystems/Locking | |
| parent | fs: add new vfs_poll and file_can_poll helpers (diff) | |
| download | linux-dev-3deb642f0de4c14f37437dd247f9c77839f043f8.tar.xz linux-dev-3deb642f0de4c14f37437dd247f9c77839f043f8.zip | |
fs: introduce new ->get_poll_head and ->poll_mask methods
->get_poll_head returns the waitqueue that the poll operation is going
to sleep on. Note that this means we can only use a single waitqueue
for the poll, unlike some current drivers that use two waitqueues for
different events. But now that we have keyed wakeups and heavily use
those for poll there aren't that many good reason left to keep the
multiple waitqueues, and if there are any ->poll is still around, the
driver just won't support aio poll.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'Documentation/filesystems/Locking')
| -rw-r--r-- | Documentation/filesystems/Locking | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 220bba28f72b..6d227f9d7bd9 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -440,6 +440,8 @@ prototypes: ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); int (*iterate) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); + struct wait_queue_head * (*get_poll_head)(struct file *, __poll_t); + __poll_t (*poll_mask) (struct file *, __poll_t); long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); long (*compat_ioctl) (struct file *, unsigned int, unsigned long); int (*mmap) (struct file *, struct vm_area_struct *); @@ -470,7 +472,7 @@ prototypes: }; locking rules: - All may block. + All except for ->poll_mask may block. ->llseek() locking has moved from llseek to the individual llseek implementations. If your fs is not using generic_file_llseek, you @@ -498,6 +500,9 @@ in sys_read() and friends. the lease within the individual filesystem to record the result of the operation +->poll_mask can be called with or without the waitqueue lock for the waitqueue +returned from ->get_poll_head. + --------------------------- dquot_operations ------------------------------- prototypes: int (*write_dquot) (struct dquot *); |