[02/12] mm: allow read-ahead with IOCB_NOWAIT set
diff mbox series

Message ID 20200526195123.29053-3-axboe@kernel.dk
State New
Headers show
Series
  • Add support for async buffered reads
Related show

Commit Message

Jens Axboe May 26, 2020, 7:51 p.m. UTC
The read-ahead shouldn't block, so allow it to be done even if
IOCB_NOWAIT is set in the kiocb.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 mm/filemap.c | 2 --
 1 file changed, 2 deletions(-)

Comments

Johannes Weiner May 26, 2020, 8:45 p.m. UTC | #1
On Tue, May 26, 2020 at 01:51:13PM -0600, Jens Axboe wrote:
> The read-ahead shouldn't block, so allow it to be done even if
> IOCB_NOWAIT is set in the kiocb.
> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Looks reasonable. Especially after patch 1 - although it seems that
even before that, IOCB_NOWAIT could have occasionally ended up in
page_cache_async_readahead(), which isn't too different from the sync
variant except for the range calculations, and may have blocked on IO
submission in the past.

Patch
diff mbox series

diff --git a/mm/filemap.c b/mm/filemap.c
index 23a051a7ef0f..80747f1377d5 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2031,8 +2031,6 @@  static ssize_t generic_file_buffered_read(struct kiocb *iocb,
 
 		page = find_get_page(mapping, index);
 		if (!page) {
-			if (iocb->ki_flags & IOCB_NOWAIT)
-				goto would_block;
 			page_cache_sync_readahead(mapping,
 					ra, filp,
 					index, last_index - index);