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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 3/3] iomap: use filemap_range_needs_writeback() for O_DIRECT reads
Date: Wed, 24 Feb 2021 09:44:55 -0700	[thread overview]
Message-ID: <20210224164455.1096727-4-axboe@kernel.dk> (raw)
In-Reply-To: <20210224164455.1096727-1-axboe@kernel.dk>

For reads, use the better variant of checking for the need to call
filemap_write_and_wait_range() when doing O_DIRECT. 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>
---
 fs/iomap/direct-io.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index e2c4991833b8..8c35a0041f0f 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		if (pos >= dio->i_size)
 			goto out_free_dio;
 
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			if (filemap_range_needs_writeback(mapping, pos, end)) {
+				ret = -EAGAIN;
+				goto out_free_dio;
+			}
+			iomap_flags |= IOMAP_NOWAIT;
+		}
+
 		if (iter_is_iovec(iter))
 			dio->flags |= IOMAP_DIO_DIRTY;
 	} else {
 		iomap_flags |= IOMAP_WRITE;
 		dio->flags |= IOMAP_DIO_WRITE;
 
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			if (filemap_range_has_page(mapping, pos, end)) {
+				ret = -EAGAIN;
+				goto out_free_dio;
+			}
+			iomap_flags |= IOMAP_NOWAIT;
+		}
+
 		/* for data sync or sync, we need sync completion processing */
 		if (iocb->ki_flags & IOCB_DSYNC)
 			dio->flags |= IOMAP_DIO_NEED_SYNC;
@@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 			dio->flags |= IOMAP_DIO_WRITE_FUA;
 	}
 
-	if (iocb->ki_flags & IOCB_NOWAIT) {
-		if (filemap_range_has_page(mapping, pos, end)) {
-			ret = -EAGAIN;
-			goto out_free_dio;
-		}
-		iomap_flags |= IOMAP_NOWAIT;
-	}
-
 	if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
 		ret = -EAGAIN;
 		if (pos >= dio->i_size || pos + count > dio->i_size)
-- 
2.30.0


  parent reply	other threads:[~2021-02-24 16:46 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 " 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 ` [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads Jens Axboe
2021-02-24 16:57   ` Matthew Wilcox
2021-02-24 17:23   ` Jan Kara
2021-02-24 16:44 ` Jens Axboe [this message]
2021-02-24 17:25   ` [PATCH 3/3] iomap: " 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 3/3] iomap: use filemap_range_needs_writeback() for " Jens Axboe
2021-02-09  7:51   ` Christoph Hellwig
2021-02-09 14:29     ` Jens Axboe

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