io_uring/wait: look at all CQ waiters on wake up

io_wake_function() returns -1 if the waiter it is called for doesn't have
enough events yet, which makes __wake_up_common() stop walking the wait
queue. That assumes that the waiters behind it can't be satisfied either.
Each waiter has its own target though, computed from the min_complete it
passed in:

  thread A: io_uring_enter(GETEVENTS, min_complete = 10)  // queued first
  thread B: io_uring_enter(GETEVENTS, min_complete = 1)
  one CQE is posted: A isn't woken, and B isn't even considered

B keeps sleeping with the event it asked for sitting in the CQ ring, until
A's demand is met or a timeout or signal ends the wait.

Return 0 to carry on with the next waiter. Only waiters whose condition
is met are woken, like before.

Fixes: bda521624e75 ("io_uring: make CQ ring wakeups be more efficient")
Assisted-by: LLM
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Link: https://patch.msgid.link/20261015-b4-io-uring-fixes-v1-20-c1556f5d7bf5@toxicpanda.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

0 files changed, 0 insertions, 0 deletions