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authorJens Axboe <axboe@kernel.dk>2020-09-14 18:30:38 +0300
committerJens Axboe <axboe@kernel.dk>2020-09-21 16:50:56 +0300
commitf5cac8b156e8b7b67bb0fdfd19900855bf9569f3 (patch)
treea54a7b2a1818cfb0b2996d6683a2d8620b17113a /fs
parent8f3d749685e48c44dbe877ac9781079d85f914c8 (diff)
downloadlinux-f5cac8b156e8b7b67bb0fdfd19900855bf9569f3.tar.xz
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: bcf5a06304d6 ("io_uring: support true async buffered reads, if file provides it") Reported-by: Zorro Lang <zlang@redhat.com> Tested-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b93355ccceeb..10d742391544 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3130,6 +3130,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
struct iov_iter __iter, *iter = &__iter;
ssize_t io_size, ret, ret2;
size_t iov_count;
+ bool no_async;
if (req->io)
iter = &req->io->rw.iter;
@@ -3147,7 +3148,8 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
kiocb->ki_flags &= ~IOCB_NOWAIT;
/* 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;
ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count);
@@ -3191,6 +3193,8 @@ copy_iov:
ret = ret2;
goto out_free;
}
+ if (no_async)
+ return -EAGAIN;
/* it's copied and will be cleaned with ->io */
iovec = NULL;
/* now use our persistent iterator, if we aren't already */