linux.git/include/uapi/linux/io_uring, branch v7.2-rc1

io_uring/zcrx: add shared-memory notification statistics

2026-05-26T16:42:01+00:00

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

2026-05-26T16:42:01+00:00

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

2026-05-26T16:42:01+00:00

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/net: allow filtering on IORING_OP_CONNECT

2026-05-14T13:23:01+00:00

This adds custom filtering for IORING_OP_CONNECT, where the target
family is always exposed, and (for AF_INET / AF_INET6) port and
address are exposed. port and v4_addr are in network byte order so
filter authors can compare against on-wire constants.

Skip population unless addr_len covers the populated fields, to
avoid leaking stale io_async_msghdr data on short connects.

Signed-off-by: Shouvik Kar 
Link: https://patch.msgid.link/20260512110242.26219-1-auxcorelabs@gmail.com
Signed-off-by: Jens Axboe

io_uring/zcrx: implement device-less mode for zcrx

2026-04-01T16:21:12+00:00

Allow creating a zcrx instance without attaching it to a net device.
All data will be copied through the fallback path. The user is also
expected to use ZCRX_CTRL_FLUSH_RQ to handle overflows as it normally
should even with a netdev, but it becomes even more relevant as there
will likely be no one to automatically pick up buffers.

Apart from that, it follows the zcrx uapi for the I/O path, and is
useful for testing, experimentation, and potentially for the copy
receive path in the future if improved.

Signed-off-by: Pavel Begunkov 
Link: https://patch.msgid.link/674f8ad679c5a0bc79d538352b3042cf0999596e.1774261953.git.asml.silence@gmail.com
[axboe: fix spelling error in uapi header and commit message]
Signed-off-by: Jens Axboe

io_uring/zcrx: move zcrx uapi into separate header

2026-03-09T13:21:54+00:00

Split out zcrx uapi into a separate file. It'll be easier to manage it
this way, and that reduces the size of a not so small io_uring.h. Since
there are users that expect that zcrx definitions come with io_uring.h,
it includes the new file.

Signed-off-by: Pavel Begunkov 
Signed-off-by: Jens Axboe

io_uring/bpf_filter: pass in expected filter payload size

2026-02-16T22:56:31+00:00

It's quite possible that opcodes that have payloads attached to them,
like IORING_OP_OPENAT/OPENAT2 or IORING_OP_SOCKET, that these paylods
can change over time. For example, on the openat/openat2 side, the
struct open_how argument is extensible, and could be extended in the
future to allow further arguments to be passed in.

Allow registration of a cBPF filter to give the size of the filter as
seen by userspace. If that filter is for an opcode that takes extra
payload data, allow it if the application payload expectation is the
same size than the kernels. If that is the case, the kernel supports
filtering on the payload that the application expects. If the size
differs, the behavior depends on the IO_URING_BPF_FILTER_SZ_STRICT flag:

1) If IO_URING_BPF_FILTER_SZ_STRICT is set and the size expectation
   differs, fail the attempt to load the filter.

2) If IO_URING_BPF_FILTER_SZ_STRICT isn't set, allow the filter if
   the userspace pdu size is smaller than what the kernel offers.

3) Regardless if IO_URING_BPF_FILTER_SZ_STRICT, fail loading the filter
   if the userspace pdu size is bigger than what the kernel supports.

An attempt to load a filter due to sizing will error with -EMSGSIZE.
For that error, the registration struct will have filter->pdu_size
populated with the pdu size that the kernel uses.

Reported-by: Christian Brauner 
Signed-off-by: Jens Axboe

io_uring/query: add query.h copyright notice

2026-02-15T21:55:44+00:00

Add a copyright notice to io_uring's query uapi header.

Signed-off-by: Pavel Begunkov 
Signed-off-by: Jens Axboe

io_uring/query: return support for custom rx page size

2026-02-15T21:55:37+00:00

Add an ability to query if the zcrx rx page size setting is available.

Note, even when the API is supported by io_uring, the registration can
still get rejected for various reasons, e.g. when the NIC or the driver
doesn't support it, when the particular specified size is unsupported,
when the memory area doesn't satisfy all requirements, etc.

Signed-off-by: Pavel Begunkov 
Signed-off-by: Jens Axboe

io_uring/bpf_filter: allow filtering on contents of struct open_how

2026-01-27T18:10:46+00:00

This adds custom filtering for IORING_OP_OPENAT and IORING_OP_OPENAT2,
where the open_how flags, mode, and resolve can be checked by filters.

Signed-off-by: Jens Axboe