diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-06-20 01:25:55 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-07-24 18:39:14 -0600 |
| commit | 305bef98870816ae58357d647521891ec558a92e (patch) | |
| tree | 48bd36c78596cd1775b197586d237e8a2bb90524 /include | |
| parent | b321823a03dc81a5b83b063e6e1904d612b53266 (diff) | |
| download | linux-305bef98870816ae58357d647521891ec558a92e.tar.bz2 | |
io_uring: hide eventfd assumptions in eventfd paths
Some io_uring-eventfd users assume that there won't be spurious wakeups.
That assumption has to be honoured by all io_cqring_ev_posted() callers,
which is inconvenient and from time to time leads to problems but should
be maintained to not break the userspace.
Instead of making the callers track whether a CQE was posted or not, hide
it inside io_eventfd_signal(). It saves ->cached_cq_tail it saw last time
and triggers the eventfd only when ->cached_cq_tail changed since then.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0ffc66bae37a2513080b601e4370e147faaa72c5.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/io_uring_types.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 6bcd7bff6479..5987f8acca38 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -314,6 +314,8 @@ struct io_ring_ctx { struct list_head defer_list; unsigned sq_thread_idle; + /* protected by ->completion_lock */ + unsigned evfd_last_cq_tail; }; enum { |