Attachment 596084 Details for Bug 837414 – upstream git commit 20d9600cb407b0b55fef6ee814b60345c6f58264

[patch] upstream git commit 20d9600cb407b0b55fef6ee814b60345c6f58264

20d9600cb407b0b55fef6ee814b60345c6f58264.patch (text/plain), 2.20 KB, created by Greg Edwards on 2012-07-03 19:48:23 UTC

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Creator: Greg Edwards

Created: 2012-07-03 19:48:23 UTC

Size: 2.20 KB

patch

obsolete

>From: David Dillow <dillowda@ornl.gov>
>Date: Thu, 20 Jan 2011 22:44:22 +0000 (-0800)
>Subject: fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio
>X-Git-Tag: v2.6.38-rc2~19^2~11
>X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git;a=commitdiff_plain;h=20d9600cb407b0b55fef6ee814b60345c6f58264
>
>fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio
>
>When using devices that support max_segments > BIO_MAX_PAGES (256), direct
>IO tries to allocate a bio with more pages than allowed, which leads to an
>oops in dio_bio_alloc().  Clamp the request to the supported maximum, and
>change dio_bio_alloc() to reflect that bio_alloc() will always return a
>bio when called with __GFP_WAIT and a valid number of vectors.
>
>[akpm@linux-foundation.org: remove redundant BUG_ON()]
>Signed-off-by: David Dillow <dillowda@ornl.gov>
>Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
>Cc: <stable@kernel.org>
>Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
>---
>
>diff --git a/fs/direct-io.c b/fs/direct-io.c
>index 85882f6..b044705 100644
>--- a/fs/direct-io.c
>+++ b/fs/direct-io.c
>@@ -325,12 +325,16 @@ void dio_end_io(struct bio *bio, int error)
> }
> EXPORT_SYMBOL_GPL(dio_end_io);
> 
>-static int
>+static void
> dio_bio_alloc(struct dio *dio, struct block_device *bdev,
> 		sector_t first_sector, int nr_vecs)
> {
> 	struct bio *bio;
> 
>+	/*
>+	 * bio_alloc() is guaranteed to return a bio when called with
>+	 * __GFP_WAIT and we request a valid number of vectors.
>+	 */
> 	bio = bio_alloc(GFP_KERNEL, nr_vecs);
> 
> 	bio->bi_bdev = bdev;
>@@ -342,7 +346,6 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev,
> 
> 	dio->bio = bio;
> 	dio->logical_offset_in_bio = dio->cur_page_fs_offset;
>-	return 0;
> }
> 
> /*
>@@ -583,8 +586,9 @@ static int dio_new_bio(struct dio *dio, sector_t start_sector)
> 		goto out;
> 	sector = start_sector << (dio->blkbits - 9);
> 	nr_pages = min(dio->pages_in_io, bio_get_nr_vecs(dio->map_bh.b_bdev));
>+	nr_pages = min(nr_pages, BIO_MAX_PAGES);
> 	BUG_ON(nr_pages <= 0);
>-	ret = dio_bio_alloc(dio, dio->map_bh.b_bdev, sector, nr_pages);
>+	dio_bio_alloc(dio, dio->map_bh.b_bdev, sector, nr_pages);
> 	dio->boundary = 0;
> out:
> 	return ret;

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Attachments on bug 837414: 596084