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io_uring: optimise rw complete error handling 

Expect read/write to succeed and create a hot path for this case, in
particular hide all error handling with resubmission under a single
check with the desired result.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-03-22 01:58:34 +00:00 committed by Jens Axboe
parent ab454438aa
commit 9532b99bd9
1 changed files with 18 additions and 15 deletions
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33
fs/io_uring.c
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@ -2487,12 +2487,14 @@ static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
if (req->rw.kiocb.ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if ((res == -EAGAIN || res == -EOPNOTSUPP) && io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE;
return;
}
if (res != req->result)
if (res != req->result) {
if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE;
return;
}
req_set_fail_links(req);
}
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_rw_kbuf(req);
__io_req_complete(req, issue_flags, res, cflags);
@ -2509,19 +2511,20 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
#ifdef CONFIG_BLOCK
if (res == -EAGAIN && io_rw_should_reissue(req)) {
if (!io_resubmit_prep(req))
req->flags |= REQ_F_DONT_REISSUE;
}
#endif
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (unlikely(res != req->result)) {
bool fail = true;
if (res != -EAGAIN && res != req->result) {
req->flags |= REQ_F_DONT_REISSUE;
req_set_fail_links(req);
#ifdef CONFIG_BLOCK
if (res == -EAGAIN && io_rw_should_reissue(req) &&
io_resubmit_prep(req))
fail = false;
#endif
if (fail) {
req_set_fail_links(req);
req->flags |= REQ_F_DONT_REISSUE;
}
}
WRITE_ONCE(req->result, res);