From 6a2414836154dc22b224c837ad7b862f78d595d1 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 28 Mar 2014 15:51:55 -0400 Subject: block: use kmalloc alignment for bio slab Various subsystems can ask the bio subsystem to create a bio slab cache with some free space before the bio. This free space can be used for any purpose. Device mapper uses this per-bio-data feature to place some target-specific and device-mapper specific data before the bio, so that the target-specific data doesn't have to be allocated separately. This per-bio-data mechanism is used in place of kmalloc, so we need the allocated slab to have the same memory alignment as memory allocated with kmalloc. Change bio_find_or_create_slab() so that it uses ARCH_KMALLOC_MINALIGN alignment when creating the slab cache. This is needed so that dm-crypt can use per-bio-data for encryption - the crypto subsystem assumes this data will have the same alignment as kmalloc'ed memory. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Acked-by: Jens Axboe --- block/bio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/bio.c b/block/bio.c index 0ec61c9..3e6331d 100644 --- a/block/bio.c +++ b/block/bio.c @@ -112,7 +112,8 @@ static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) bslab = &bio_slabs[entry]; snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); - slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL); + slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN, + SLAB_HWCACHE_ALIGN, NULL); if (!slab) goto out_unlock; -- cgit v1.1