Commit f5cac8b1 authored by Jens Axboe's avatar Jens Axboe

io_uring: don't use retry based buffered reads for non-async bdev

Some block devices, like dm, bubble back -EAGAIN through the completion
handler. We check for this in io_read(), but don't honor it for when
we have copied the iov. Return -EAGAIN for this case before retrying,
to force punt to io-wq.

Fixes: bcf5a063 ("io_uring: support true async buffered reads, if file provides it")
Reported-by: default avatarZorro Lang <zlang@redhat.com>
Tested-by: default avatarZorro Lang <zlang@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8f3d7496
...@@ -3130,6 +3130,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock, ...@@ -3130,6 +3130,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
struct iov_iter __iter, *iter = &__iter; struct iov_iter __iter, *iter = &__iter;
ssize_t io_size, ret, ret2; ssize_t io_size, ret, ret2;
size_t iov_count; size_t iov_count;
bool no_async;
if (req->io) if (req->io)
iter = &req->io->rw.iter; iter = &req->io->rw.iter;
...@@ -3147,7 +3148,8 @@ static int io_read(struct io_kiocb *req, bool force_nonblock, ...@@ -3147,7 +3148,8 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
kiocb->ki_flags &= ~IOCB_NOWAIT; kiocb->ki_flags &= ~IOCB_NOWAIT;
/* If the file doesn't support async, just async punt */ /* If the file doesn't support async, just async punt */
if (force_nonblock && !io_file_supports_async(req->file, READ)) no_async = force_nonblock && !io_file_supports_async(req->file, READ);
if (no_async)
goto copy_iov; goto copy_iov;
ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count); ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count);
...@@ -3191,6 +3193,8 @@ static int io_read(struct io_kiocb *req, bool force_nonblock, ...@@ -3191,6 +3193,8 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
ret = ret2; ret = ret2;
goto out_free; goto out_free;
} }
if (no_async)
return -EAGAIN;
/* it's copied and will be cleaned with ->io */ /* it's copied and will be cleaned with ->io */
iovec = NULL; iovec = NULL;
/* now use our persistent iterator, if we aren't already */ /* now use our persistent iterator, if we aren't already */
......
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