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io_uring: offload write to async worker in case of -EAGAIN 

In case of direct write -EAGAIN will be returned if page cache was
previously populated.  To avoid immediate completion of a request
with -EAGAIN error write has to be offloaded to the async worker,
like io_read() does.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Roman Penyaev 2019-03-25 20:09:24 +01:00 committed by Jens Axboe
parent e6d1fa584e
commit 9bf7933fc3
1 changed files with 15 additions and 1 deletions
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16
fs/io_uring.c
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@ -1022,6 +1022,8 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
if (!ret) {
ssize_t ret2;
/*
* Open-code file_start_write here to grab freeze protection,
* which will be released by another thread in
@ -1036,7 +1038,19 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;
io_rw_done(kiocb, call_write_iter(file, kiocb, &iter));
ret2 = call_write_iter(file, kiocb, &iter);
if (!force_nonblock || ret2 != -EAGAIN) {
io_rw_done(kiocb, ret2);
} else {
/*
* If ->needs_lock is true, we're already in async
* context.
*/
if (!s->needs_lock)
io_async_list_note(WRITE, req, iov_count);
ret = -EAGAIN;
}
}
out_free:
kfree(iovec);