linux.git/io_uring/zcrx.h, branch master

io_uring/zcrx: rename notif to event

2026-07-22T15:48:42Z

"Notification" is too long and the abbreviated version is used in several places, which is inconsistent and more ambiguous for users. Rename it to event, which is easier to keep consistent. To keep the change small, only change uapi/ + do necessary fix ups, and the rest of internals can be adjusted in the next release. Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/f95ca6717da3c8d3649a1a7f0d883a563f545052.1784726895.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: rename ZCRX_NOTIF_NO_BUFFERS

2026-07-22T15:48:42Z

ZCRX_NOTIF_NO_BUFFERS tells when page pool fails to allocate memory from zcrx. "No buffers" could be more confusing, rename it to ZCRX_NOTIF_ALLOC_FAIL. Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/29bd4fc069bc89691868beba0627ffbe570c2722.1784726895.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: drop "notif" from stats struct names

2026-07-22T15:48:41Z

Keep zcrx statistics generic and don't stick "notif" to its uapi definitions. Stats dosn't need to be bound to notification details, it makes it cleaner and more readable. Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/6a39676b6f71b67d3f89c6ebab7a3739873834a3.1784726895.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: add shared-memory notification statistics

2026-05-26T16:42:01Z

Add support for an optional stats struct embedded in the refill queue region, allowing userspace to monitor copy-fallback in real-time. Userspace queries the stats struct size and alignment via IO_URING_QUERY_ZCRX_NOTIF (notif_stats_size / notif_stats_alignment), then provides a stats_offset in zcrx_notification_desc pointing to a location within the refill queue region. The kernel updates the stats counters in-place on every copy-fallback event. Signed-off-by: Clément Léger [pavel: rename io_uring_zcrx_notif_stats] Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/f6af5a21015efea4b733b9d77aba22c637788fe4.1779189667.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: notify user on frag copy fallback

2026-05-26T16:42:01Z

Add a ZCRX_NOTIF_COPY notification type to signal userspace when a received fragment could not be delivered using zero-copy and was instead copied into a buffer. Signed-off-by: Clément Léger Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/3d54bcd8bf10b3a1e88beb0cd39c40c3937bea4f.1779189667.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: notify user when out of buffers

2026-05-26T16:42:01Z

There are currently no easy ways for the user to know if zcrx is out of buffers and page pool fails to allocate. Add uapi for zcrx to communicate it back. It's implemented as a separate CQE, which for now is posted to the creator ctx. To use it, on registration the user space needs to pass an instance of struct zcrx_notification_desc, which tells the kernel the user_data for resulting CQEs and which event types are expected / allowed. When an allowed event happens, zcrx will post a CQE containing the specified user_data, and lower bits of cqe->res will be set to the event mask. Before the kernel could post another notification of the given type, the user needs to acknowledge that it processed the previous one by issuing IORING_REGISTER_ZCRX_CTRL with ZCRX_CTRL_ARM_NOTIFICATION. The only notification type the patch implements is ZCRX_NOTIF_NO_BUFFERS, but we'll need more of them in the future. Co-developed-by: Vishwanath Seshagiri Signed-off-by: Pavel Begunkov Signed-off-by: Vishwanath Seshagiri Link: https://patch.msgid.link/35cd307a03a43583838a2e151fc641c69abd786f.1779189667.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: add ctx pointer to zcrx

2026-05-26T16:42:01Z

zcrx will need to have a pointer to an owning ctx to communicate different events. Reference the ctx while it's attached to zcrx, and rely on zcrx termination to drop the ctx to avoid circular ref deps. Co-developed-by: Vishwanath Seshagiri Signed-off-by: Pavel Begunkov Signed-off-by: Vishwanath Seshagiri Link: https://patch.msgid.link/b60514b3d1bd92f571e3bd91751166f8c3599256.1779189667.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: rename zcrx [un]register functions

2026-04-01T16:21:13Z

Drop "ifqs" from function names, as it refers to an interface queue and there might be none once a device-less mode is introduced. Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/657874acd117ec30fa6f45d9d844471c753b5a0f.1774261953.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: cache fallback availability in zcrx ctx

2026-04-01T16:21:13Z

Store a flag in struct io_zcrx_ifq telling if the backing memory is normal page or dmabuf based. It was looking it up from the area, however it logically allocates from the zcrx ctx and not a particular area, and once we add more than one area it'll become a mess. Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/65e75408a7758fe7e60fae89b7a8d5ae4857f515.1774261953.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/zcrx: add a struct for refill queue

2026-04-01T16:21:12Z

Add a new structure that keeps the refill queue state. It's cleaner and will be useful once we introduce multiple refill queues. Signed-off-by: Pavel Begunkov Link: https://patch.msgid.link/4ce200da1ff0309c377293b949200f95f80be9ae.1774261953.git.asml.silence@gmail.com Signed-off-by: Jens Axboe