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btrfs: add helper to initialize the non-bio part of btrfs_io_bio

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We use btrfs_bioset for bios and ask to allocate the entire size of
btrfs_io_bio from btrfs bio_alloc_bioset. The member 'bio' is
initialized but the bytes from 0 to offset of 'bio' are left
uninitialized. Although we initialize some of the members in our
helpers, we should initialize the whole structures.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2017-06-12 17:29:39 +02:00
parent fa1bcbe0a5
commit 184f999e12
1 changed files with 14 additions and 16 deletions
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30
fs/btrfs/extent_io.c
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@ -2653,6 +2653,16 @@ readpage_ok:
bio_put(bio);
}
/*
* Initialize the members up to but not including 'bio'. Use after allocating a
* new bio by bio_alloc_bioset as it does not initialize the bytes outside of
* 'bio' because use of __GFP_ZERO is not supported.
*/
static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
{
memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
}
/*
* The following helpers allocate a bio. As it's backed by a bioset, it'll
* never fail. We're returning a bio right now but you can call btrfs_io_bio
@ -2660,16 +2670,12 @@ readpage_ok:
*/
struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte)
{
struct btrfs_io_bio *btrfs_bio;
struct bio *bio;
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, btrfs_bioset);
bio->bi_bdev = bdev;
bio->bi_iter.bi_sector = first_byte >> 9;
btrfs_bio = btrfs_io_bio(bio);
btrfs_bio->csum = NULL;
btrfs_bio->csum_allocated = NULL;
btrfs_bio->end_io = NULL;
btrfs_io_bio_init(btrfs_io_bio(bio));
return bio;
}
@ -2681,24 +2687,18 @@ struct bio *btrfs_bio_clone(struct bio *bio)
/* Bio allocation backed by a bioset does not fail */
new = bio_clone_fast(bio, GFP_NOFS, btrfs_bioset);
btrfs_bio = btrfs_io_bio(new);
btrfs_bio->csum = NULL;
btrfs_bio->csum_allocated = NULL;
btrfs_bio->end_io = NULL;
btrfs_io_bio_init(btrfs_bio);
btrfs_bio->iter = bio->bi_iter;
return new;
}
struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
struct btrfs_io_bio *btrfs_bio;
struct bio *bio;
/* Bio allocation backed by a bioset does not fail */
bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
btrfs_bio = btrfs_io_bio(bio);
btrfs_bio->csum = NULL;
btrfs_bio->csum_allocated = NULL;
btrfs_bio->end_io = NULL;
btrfs_io_bio_init(btrfs_io_bio(bio));
return bio;
}
@ -2712,9 +2712,7 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
ASSERT(bio);
btrfs_bio = btrfs_io_bio(bio);
btrfs_bio->csum = NULL;
btrfs_bio->csum_allocated = NULL;
btrfs_bio->end_io = NULL;
btrfs_io_bio_init(btrfs_bio);
bio_trim(bio, offset >> 9, size >> 9);
btrfs_bio->iter = bio->bi_iter;