io_uring/register: keep 128b SQEs intact on resize

On a ring with IORING_SETUP_SQE_MIXED a 128b SQE takes two entries that
have to be contiguous in memory, io_init_req() fails it with -EINVAL if
it starts on the last entry of the SQ ring. The entry a pending SQE ends
up in after IORING_REGISTER_RESIZE_RINGS depends on the size of the new
ring, and nothing takes care of that. With four entries instead of eight,
a 128b SQE which was fine in entries 3 and 4 is split up between entry 3
and entry 0. The resize succeeds, and the request fails later on.

If the ring has an SQ array, the second half is also taken from the
wrong place unless the array happens to map the following index to the
following entry. The submission side doesn't look at the array for the
second half.

Do what is done for 32b CQEs on IORING_SETUP_CQE_MIXED rings: fail the
resize with -EOVERFLOW if a 128b SQE would wrap. And copy the second half
from where it is.

Fixes: 1cba30bf9fdd ("io_uring: add support for IORING_SETUP_SQE_MIXED")
Assisted-by: LLM
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Link: https://patch.msgid.link/20261015-b4-io-uring-fixes-v1-27-c1556f5d7bf5@toxicpanda.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

0 files changed, 0 insertions, 0 deletions