linux.git/io_uring/cancel.c, branch v6.0

io_uring: fix off-by-one in sync cancelation file check

2022-08-23T13:26:08+00:00

The passed in index should be validated against the number of registered
files we have, it needs to be smaller than the index value to avoid going
one beyond the end.

Fixes: 78a861b94959 ("io_uring: add sync cancelation API through io_uring_register()")
Reported-by: Luo Likang 
Signed-off-by: Jens Axboe

io_uring: make io_kiocb_to_cmd() typesafe

2022-08-12T23:01:00+00:00

We need to make sure (at build time) that struct io_cmd_data is not
casted to a structure that's larger.

Signed-off-by: Stefan Metzmacher 
Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe

io_uring: add sync cancelation API through io_uring_register()

2022-07-25T00:39:15+00:00

The io_uring cancelation API is async, like any other API that we expose
there. For the case of finding a request to cancel, or not finding one,
it is fully sync in that when submission returns, the CQE for both the
cancelation request and the targeted request have been posted to the
CQ ring.

However, if the targeted work is being executed by io-wq, the API can
only start the act of canceling it. This makes it difficult to use in
some circumstances, as the caller then has to wait for the CQEs to come
in and match on the same cancelation data there.

Provide a IORING_REGISTER_SYNC_CANCEL command for io_uring_register()
that does sync cancelations, always. For the io-wq case, it'll wait
for the cancelation to come in before returning. The only expected
returns from this API is:

0		Request found and canceled fine.
> 0		Requests found and canceled. Only happens if asked to
		cancel multiple requests, and if the work wasn't in
		progress.
-ENOENT		Request not found.
-ETIME		A timeout on the operation was requested, but the timeout
		expired before we could cancel.

and we won't get -EALREADY via this API.

If the timeout value passed in is -1 (tv_sec and tv_nsec), then that
means that no timeout is requested. Otherwise, the timespec passed in
is the amount of time the sync cancel will wait for a successful
cancelation.

Link: https://github.com/axboe/liburing/discussions/608
Signed-off-by: Jens Axboe

io_uring: add IORING_ASYNC_CANCEL_FD_FIXED cancel flag

2022-07-25T00:39:15+00:00

In preparation for not having a request to pass in that carries this
state, add a separate cancelation flag that allows the caller to ask
for a fixed file for cancelation.

Signed-off-by: Jens Axboe

io_uring: have cancelation API accept io_uring_task directly

2022-07-25T00:39:15+00:00

We just use the io_kiocb passed in to find the io_uring_task, and we
already pass in the ctx via cd->ctx anyway.

Signed-off-by: Jens Axboe

io_uring: kill extra io_uring_types.h includes

2022-07-25T00:39:14+00:00

io_uring/io_uring.h already includes io_uring_types.h, no need to
include it every time. Kill it in a bunch of places, it prepares us for
following patches.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/94d8c943fbe0ef949981c508ddcee7fc1c18850f.1655384063.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

io_uring: propagate locking state to poll cancel

2022-07-25T00:39:13+00:00

Poll cancellation will be soon need to grab ->uring_lock inside, pass
the locking state, i.e. issue_flags, inside the cancellation functions.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/b86781d047727c07163443b57551a3fa57c7c5e1.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu 
Signed-off-by: Jens Axboe

io_uring: introduce a struct for hash table

2022-07-25T00:39:13+00:00

Instead of passing around a pointer to hash buckets, add a bit of type
safety and wrap it into a structure.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/d65bc3faba537ec2aca9eabf334394936d44bd28.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu 
Signed-off-by: Jens Axboe

io_uring: clean up io_try_cancel

2022-07-25T00:39:13+00:00

Get rid of an unnecessary extra goto in io_try_cancel() and simplify the
function.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/48cf5417b43a8386c6c364dba1ad9b4c7382d158.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu 
Signed-off-by: Jens Axboe

io_uring: switch cancel_hash to use per entry spinlock

2022-07-25T00:39:13+00:00

Add a new io_hash_bucket structure so that each bucket in cancel_hash
has separate spinlock. Use per entry lock for cancel_hash, this removes
some completion lock invocation and remove contension between different
cancel_hash entries.

Signed-off-by: Hao Xu 
Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/05d1e135b0c8bce9d1441e6346776589e5783e26.1655371007.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe