The patch titled
fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio
has been added to the -mm tree. Its filename is
fs-direct-ioc-dont-try-to-allocate-more-than-bio_max_pages-in-a-bio.patch
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------------------------------------------------------
Subject: fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio
From: David Dillow <dillowda@xxxxxxxx>
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.
Signed-off-by: David Dillow <dillowda@xxxxxxxx>
Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/direct-io.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff -puN fs/direct-io.c~fs-direct-ioc-dont-try-to-allocate-more-than-bio_max_pages-in-a-bio fs/direct-io.c
--- a/fs/direct-io.c~fs-direct-ioc-dont-try-to-allocate-more-than-bio_max_pages-in-a-bio
+++ a/fs/direct-io.c
@@ -325,13 +325,18 @@ void dio_end_io(struct bio *bio, int err
}
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);
+ BUG_ON(!bio);
bio->bi_bdev = bdev;
bio->bi_sector = first_sector;
@@ -342,7 +347,6 @@ dio_bio_alloc(struct dio *dio, struct bl
dio->bio = bio;
dio->logical_offset_in_bio = dio->cur_page_fs_offset;
- return 0;
}
/*
@@ -583,8 +587,9 @@ static int dio_new_bio(struct dio *dio,
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;
_
Patches currently in -mm which might be from dillowda@xxxxxxxx are
origin.patch
fs-direct-ioc-dont-try-to-allocate-more-than-bio_max_pages-in-a-bio.patch
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