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[76.191.17.161]) by smtp.googlemail.com with ESMTPSA id r24sm6867968ioa.5.2021.10.18.07.56.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Oct 2021 07:56:20 -0700 (PDT) From: Noah Goldstein Cc: goldstein.w.n@gmail.com, axboe@kernel.dk, asml.silence@gmail.com, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] fs/io_uring: Hoist ret2 == -EAGAIN check in tail of io_write Date: Mon, 18 Oct 2021 10:56:13 -0400 Message-Id: <20211018145613.22186-1-goldstein.w.n@gmail.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20211018070242.20325-1-goldstein.w.n@gmail.com> References: <20211018070242.20325-1-goldstein.w.n@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This commit reorganizes the branches in the tail of io_write so that the 'ret2 == -EAGAIN' check is not repeated and done first. The previous version was duplicating the 'ret2 == -EAGAIN'. As well 'ret2 != -EAGAIN' gurantees the 'done:' path so it makes sense to move that check to the front before the likely more expensive branches which require memory derefences. Signed-off-by: Noah Goldstein --- fs/io_uring.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index d1e672e7a2d1..18293407e8bc 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3648,21 +3648,19 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) */ if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) ret2 = -EAGAIN; - /* no retry on NONBLOCK nor RWF_NOWAIT */ - if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) - goto done; - if (!force_nonblock || ret2 != -EAGAIN) { - /* IOPOLL retry should happen for io-wq threads */ - if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) - goto copy_iov; -done: + + if (ret2 != -EAGAIN || + /* no retry on NONBLOCK nor RWF_NOWAIT */ + (req->flags & REQ_F_NOWAIT) + /* IOPOLL retry should happen for io-wq threads */ + || (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))) { kiocb_done(kiocb, ret2, issue_flags); } else { copy_iov: iov_iter_restore(&s->iter, &s->iter_state); ret = io_setup_async_rw(req, iovec, s, false); return ret ?: -EAGAIN; - } +} out_free: /* it's reportedly faster than delegating the null check to kfree() */ if (iovec) -- 2.29.2