Ming Lei 84ea891dc8 ublk: make sure io cmd handled in submitter task context
[ Upstream commit 3421c7f68bba52281bbb38bc76c18dc03cb689e4 ]

In well-done ublk server implementation, ublk io command won't be
linked into any link chain. Meantime they are always handled in no-wait
style, so basically io cmd is always handled in submitter task context.

However, the server may set IOSQE_ASYNC, or io command is linked to one
chain mistakenly, then we may still run into io-wq context and
ctx->uring_lock isn't held.

So in case of IO_URING_F_UNLOCKED, schedule this command by
io_uring_cmd_complete_in_task to force running it in submitter task. Then
ublk_ch_uring_cmd_local() is guaranteed to run with context uring_lock held,
and we needn't to worry about sync among submission code path any more.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20231009093324.957829-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: c6a45ee7607d ("ublk: prevent invalid access with DEBUG")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-11 15:21:31 +01:00
2022-09-28 09:02:20 +02:00
2025-12-07 06:18:54 +09:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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