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io_uring: fix overlapped memcpy in io_req_map_rw()

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When io_req_map_rw() is called from io_rw_prep_async(), it memcpy()
iorw->iter into itself. Even though it doesn't lead to an error, such a
memcpy()'s aliasing rules violation is considered to be a bad practise.

Inline io_req_map_rw() into io_rw_prep_async(). We don't really need any
remapping there, so it's much simpler than the generic implementation.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-09-06 00:45:47 +03:00 committed by Jens Axboe
parent afb87658f8
commit ab0b196ce5
1 changed files with 4 additions and 1 deletions
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5
fs/io_uring.c
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@ -3071,7 +3071,10 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw,
if (unlikely(ret < 0))
return ret;
io_req_map_rw(req, iov, iorw->fast_iov, &iorw->iter);
iorw->bytes_done = 0;
iorw->free_iovec = iov;
if (iov)
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}