user/sven/linux.git/include/uapi/linux/io_uring.h, branch v6.1.56

io_uring: Replace 0-length array with flexible array

2023-03-10T08:34:03Z

commit 36632d062975a9ff4410c90dd6d37922b68d0920 upstream. Zero-length arrays are deprecated[1]. Replace struct io_uring_buf_ring's "bufs" with a flexible array member. (How is the size of this array verified?) Detected with GCC 13, using -fstrict-flex-arrays=3: In function 'io_ring_buffer_select', inlined from 'io_buffer_select' at io_uring/kbuf.c:183:10: io_uring/kbuf.c:141:23: warning: array subscript 255 is outside the bounds of an interior zero-length array 'struct io_uring_buf[0]' [-Wzero-length-bounds] 141 | buf = &br->bufs[head]; | ^~~~~~~~~~~~~~~ In file included from include/linux/io_uring.h:7, from io_uring/kbuf.c:10: include/uapi/linux/io_uring.h: In function 'io_buffer_select': include/uapi/linux/io_uring.h:628:41: note: while referencing 'bufs' 628 | struct io_uring_buf bufs[0]; | ^~~~ [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Cc: Jens Axboe Cc: Pavel Begunkov Cc: "Gustavo A. R. Silva" Cc: stable@vger.kernel.org Cc: io-uring@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20230105190507.gonna.131-kees@kernel.org Signed-off-by: Greg Kroah-Hartman

io_uring/net: introduce IORING_SEND_ZC_REPORT_USAGE flag

2022-12-31T12:33:11Z

commit e307e6698165ca6508ed42c69cb1be76c8eb6a3c upstream. It might be useful for applications to detect if a zero copy transfer with SEND[MSG]_ZC was actually possible or not. The application can fallback to plain SEND[MSG] in order to avoid the overhead of two cqes per request. Or it can generate a log message that could indicate to an administrator that no zero copy was possible and could explain degraded performance. Cc: stable@vger.kernel.org # 6.1 Link: https://lore.kernel.org/io-uring/fb6a7599-8a9b-15e5-9b64-6cd9d01c6ff4@gmail.com/T/#m2b0d9df94ce43b0e69e6c089bdff0ce6babbdfaa Signed-off-by: Stefan Metzmacher Reviewed-by: Pavel Begunkov Link: https://lore.kernel.org/r/8945b01756d902f5d5b0667f20b957ad3f742e5e.1666895626.git.metze@samba.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: fix typo in io_uring.h comment

2022-11-06T20:17:27Z

Just a basic s/thig/this swap, fixing up a typo introduced by a commit added in the 6.1 release. Fixes: 9cda70f622cd ("io_uring: introduce fixed buffer support for io_uring_cmd") Signed-off-by: Jens Axboe

io_uring: introduce fixed buffer support for io_uring_cmd

2022-09-30T13:50:59Z

Add IORING_URING_CMD_FIXED flag that is to be used for sending io_uring command with previously registered buffers. User-space passes the buffer index in sqe->buf_index, same as done in read/write variants that uses fixed buffers. Signed-off-by: Anuj Gupta Signed-off-by: Kanchan Joshi Link: https://lore.kernel.org/r/20220930062749.152261-3-anuj20.g@samsung.com [axboe: shuffle valid flags check before acting on it] Signed-off-by: Jens Axboe

io_uring/net: zerocopy sendmsg

2022-09-21T19:15:02Z

Add a zerocopy version of sendmsg. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/6aabc4bdfc0ec78df6ec9328137e394af9d4e7ef.1663668091.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring: add IORING_SETUP_DEFER_TASKRUN

2022-09-21T16:30:42Z

Allow deferring async tasks until the user calls io_uring_enter(2) with the IORING_ENTER_GETEVENTS flag. Enable this mode with a flag at io_uring_setup time. This functionality requires that the later io_uring_enter will be called from the same submission task, and therefore restrict this flag to work only when IORING_SETUP_SINGLE_ISSUER is also set. Being able to hand pick when tasks are run prevents the problem where there is current work to be done, however task work runs anyway. For example, a common workload would obtain a batch of CQEs, and process each one. Interrupting this to additional taskwork would add latency but not gain anything. If instead task work is deferred to just before more CQEs are obtained then no additional latency is added. The way this is implemented is by trying to keep task work local to a io_ring_ctx, rather than to the submission task. This is required, as the application will want to wake up only a single io_ring_ctx at a time to process work, and so the lists of work have to be kept separate. This has some other benefits like not having to check the task continually in handle_tw_list (and potentially unlocking/locking those), and reducing locks in the submit & process completions path. There are networking cases where using this option can reduce request latency by 50%. For example a contrived example using [1] where the client sends 2k data and receives the same data back while doing some system calls (to trigger task work) shows this reduction. The reason ends up being that if sending responses is delayed by processing task work, then the client side sits idle. Whereas reordering the sends first means that the client runs it's workload in parallel with the local task work. [1]: Using https://github.com/DylanZA/netbench/tree/defer_run Client: ./netbench --client_only 1 --control_port 10000 --host --tx "epoll --threads 16 --per_thread 1 --size 2048 --resp 2048 --workload 1000" Server: ./netbench --server_only 1 --control_port 10000 --rx "io_uring --defer_taskrun 0 --workload 100" --rx "io_uring --defer_taskrun 1 --workload 100" Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220830125013.570060-5-dylany@fb.com Signed-off-by: Jens Axboe

io_uring/net: simplify zerocopy send user API

2022-09-01T15:13:33Z

Following user feedback, this patch simplifies zerocopy send API. One of the main complaints is that the current API is difficult with the userspace managing notification slots, and then send retries with error handling make it even worse. Instead of keeping notification slots change it to the per-request notifications model, which posts both completion and notification CQEs for each request when any data has been sent, and only one CQE if it fails. All notification CQEs will have IORING_CQE_F_NOTIF set and IORING_CQE_F_MORE in completion CQEs indicates whether to wait a notification or not. IOSQE_CQE_SKIP_SUCCESS is disallowed with zerocopy sends for now. This is less flexible, but greatly simplifies the user API and also the kernel implementation. We reuse notif helpers in this patch, but in the future there won't be need for keeping two requests. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/95287640ab98fc9417370afb16e310677c63e6ce.1662027856.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/notif: remove notif registration

2022-09-01T15:13:33Z

We're going to remove the userspace exposed zerocopy notification API, remove notification registration. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/6ff00b97be99869c386958a990593c9c31cf105b.1662027856.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

Revert "io_uring: rename IORING_OP_FILES_UPDATE"

2022-09-01T15:13:33Z

This reverts commit 4379d5f15b3fd4224c37841029178aa8082a242e. We removed notification flushing, also cleanup uapi preparation changes to not pollute it. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/89edc3905350f91e1b6e26d9dbf42ee44fd451a2.1662027856.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

Revert "io_uring: add zc notification flush requests"

2022-09-01T15:13:33Z

This reverts commit 492dddb4f6e3a5839c27d41ff1fecdbe6c3ab851. Soon we won't have the very notion of notification flushing, so remove notification flushing requests. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/8850334ca56e65b413cb34fd158db81d7b2865a3.1662027856.git.asml.silence@gmail.com Signed-off-by: Jens Axboe