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From: Jens Axboe <axboe@kernel.dk>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: akpm@linux-foundation.org, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads
Date: Wed, 24 Feb 2021 09:44:54 -0700	[thread overview]
Message-ID: <20210224164455.1096727-3-axboe@kernel.dk> (raw)
In-Reply-To: <20210224164455.1096727-1-axboe@kernel.dk>

For the generic page cache read helper, use the better variant of checking
for the need to call filemap_write_and_wait_range() when doing O_DIRECT
reads. This avoids falling back to the slow path for IOCB_NOWAIT, if there
are no pages to wait for (or write out).

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 mm/filemap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 13338f877677..77f1b527541e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2645,8 +2645,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 
 		size = i_size_read(inode);
 		if (iocb->ki_flags & IOCB_NOWAIT) {
-			if (filemap_range_has_page(mapping, iocb->ki_pos,
-						   iocb->ki_pos + count - 1))
+			if (filemap_range_needs_writeback(mapping, iocb->ki_pos,
+						iocb->ki_pos + count - 1))
 				return -EAGAIN;
 		} else {
 			retval = filemap_write_and_wait_range(mapping,
-- 
2.30.0



  parent reply	other threads:[~2021-02-24 16:45 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-24 16:44 [PATCHSET v3 0/3] Improve IOCB_NOWAIT O_DIRECT reads Jens Axboe
2021-02-24 16:44 ` [PATCH 1/3] mm: provide filemap_range_needs_writeback() helper Jens Axboe
2021-02-24 16:50   ` Matthew Wilcox
2021-02-24 16:53     ` Jens Axboe
2021-02-24 17:22   ` Jan Kara
2021-02-24 16:44 ` Jens Axboe [this message]
2021-02-24 16:57   ` [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads Matthew Wilcox
2021-02-24 17:23   ` Jan Kara
2021-02-24 16:44 ` [PATCH 3/3] iomap: " Jens Axboe
2021-02-24 17:25   ` Jan Kara
  -- strict thread matches above, loose matches on Subject: below --
2021-02-09  2:30 [PATCHSET v2 0/3] Improve IOCB_NOWAIT " Jens Axboe
2021-02-09  2:30 ` [PATCH 2/3] mm: use filemap_range_needs_writeback() for " Jens Axboe
2021-02-09  7:48   ` Christoph Hellwig
2021-02-09 14:27     ` Jens Axboe

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