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io_uring: do not recycle buffer in READV

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READV cannot recycle buffers as it would lose some of the data required to
reimport that buffer.

Reported-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Fixes: b66e65f414 ("io_uring: never call io_buffer_select() for a buffer re-select")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220721131325.624788-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Dylan Yudaken 2022-07-21 06:13:25 -07:00 committed by Jens Axboe
parent ec8516f3b7
commit 934447a603
1 changed files with 8 additions and 0 deletions
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8
fs/io_uring.c
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@ -1737,6 +1737,14 @@ static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
(req->flags & REQ_F_PARTIAL_IO))
return;
/*
* READV uses fields in `struct io_rw` (len/addr) to stash the selected
* buffer data. However if that buffer is recycled the original request
* data stored in addr is lost. Therefore forbid recycling for now.
*/
if (req->opcode == IORING_OP_READV)
return;
/*
* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
* the flag and hence ensure that bl->head doesn't get incremented.