[GIT PULL] Fix memory ordering in sq_ring_needs_enter

[almogkh]

A full memory barrier is required between the store to the SQ tail in
__io_uring_flush_sq and the load of the flags in sq_ring_needs_enter
to prevent a situation where the kernel thread goes to sleep while
sq_ring_needs_enter returns false

Fixes: #541
Signed-off-by: Almog Khaikin [email protected]

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git request-pull output:

The following changes since commit 2de98320d5b02951936fc0ab677dd01e4fb2a7a7:

  src/Makefile: Don't use stack protector for all builds by default (2022-02-25 07:17:37 -0700)

are available in the Git repository at:

  https://github.com/almogkh/liburing fix-needenter

for you to fetch changes up to 748fd137c7f70d352fdc546535cf52108352e827:

  Fix memory ordering in sq_ring_needs_enter (2022-03-05 19:18:24 +0200)

----------------------------------------------------------------
Almog Khaikin (1):
      Fix memory ordering in sq_ring_needs_enter

 src/include/liburing/barrier.h | 8 ++++++++
 src/queue.c                    | 6 ++++++
 2 files changed, 14 insertions(+)

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src/queue: don't flush SQ ring for new wait interface

If we have IORING_FEAT_EXT_ARG, then timeouts are done through the
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Fixes: https://github.com/axboe/liburing/issues/402
Signed-off-by: Jens Axboe <[email protected]>

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