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Fri, 23 Jan 2026 11:04:07 -0800 (PST) Message-ID: <2d2da3b2-74c6-4605-8d13-3f0cdc67191e@kernel.dk> Date: Fri, 23 Jan 2026 12:04:07 -0700 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH liburing 0/2] Add support for IORING_SETUP_SQ_REWIND To: Pavel Begunkov , io-uring@vger.kernel.org References: <176912275112.522897.5400530813917730862.b4-ty@kernel.dk> <517fc5f0-5e6d-46ef-800d-9ef4428278a1@kernel.dk> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/23/26 7:14 AM, Pavel Begunkov wrote: > On 1/22/26 23:05, Jens Axboe wrote: >> On 1/22/26 3:59 PM, Jens Axboe wrote: >>> >>> On Wed, 21 Jan 2026 22:23:20 +0000, Pavel Begunkov wrote: >>>> Add liburing support and tests for IORING_SETUP_SQ_REWIND. >>>> >>>> Pavel Begunkov (2): >>>> src/queue: Add support for non circular SQ >>>> tests: add SETUP_SQ_REWIND tests >>>> >>>> src/include/liburing.h | 5 ++++- >>>> src/include/liburing/io_uring.h | 12 ++++++++++++ >>>> src/queue.c | 5 +++++ >>>> test/test.h | 2 ++ >>>> 4 files changed, 23 insertions(+), 1 deletion(-) >>>> >>>> [...] >>> >>> Applied, thanks! >>> >>> [1/2] src/queue: Add support for non circular SQ >>> commit: c22129cf0b8c936eb478d920ef84e53d89c6a5cc >>> [2/2] tests: add SETUP_SQ_REWIND tests >>> commit: 346c063d16bda52f02d00feb744aafe35b4002a9 >> >> Hmm I do think you're missing some spots though, no? >> >> diff --git a/src/include/liburing.h b/src/include/liburing.h >> index 987b28aaf99e..016be1e80ef2 100644 >> --- a/src/include/liburing.h >> +++ b/src/include/liburing.h >> @@ -1702,8 +1702,13 @@ IOURINGINLINE unsigned io_uring_load_sq_head(const struct io_uring *ring) >> IOURINGINLINE unsigned io_uring_sq_ready(const struct io_uring *ring) >> LIBURING_NOEXCEPT >> { >> + unsigned head = 0; >> + >> + if (!(ring->flags & IORING_SETUP_SQ_REWIND)) >> + head = io_uring_load_sq_head(ring); > > The head should already be zero. Actually, sounds like the get_sqe > hunk from the patch is not needed either. Yeah agree, I think they are both false alarms. Might warrant a comment though. Or maybe we just fold it into io_uring_load_sq_head()? -- Jens Axboe