[PATCH v2] btrfs: replace kcalloc() calls to kzalloc_objs()

[Miquel Sabaté Solà]

Commit 2932ba8d9c99 ("slab: Introduce kmalloc_obj() and family")
introduced, among many others, the kzalloc_objs() helper, which has some
benefits over kcalloc(). Namely, internal introspection of the allocated
type now becomes possible, allowing for future alignment-aware choices
to be made by the allocator and future hardening work that can be type
sensitive. Dropping 'sizeof' comes also as a nice side-effect.

Moreover, this also allows us to be in line with the recent tree-wide
migration to the kmalloc_obj() and family of helpers. See
commit 69050f8d6d07 ("treewide: Replace kmalloc with kmalloc_obj for
non-scalar types").

Reviewed-by: Kees Cook <kees@xxxxxxxxxx>
Signed-off-by: Miquel Sabaté Solà <mssola@xxxxxxxxxx>
---
Changes since v1:
  - Better commit message as suggested by Johannes Thumshirn and Qu Wenruo.
  - Link: https://lore.kernel.org/all/20260223234451.277369-1-mssola@xxxxxxxxxx/

 fs/btrfs/block-group.c       | 2 +-
 fs/btrfs/raid56.c            | 8 ++++----
 fs/btrfs/tests/zoned-tests.c | 2 +-
 fs/btrfs/volumes.c           | 6 ++----
 fs/btrfs/zoned.c             | 5 ++---
 5 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 37bea850b3f0..8d85b4707690 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2239,7 +2239,7 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
 		io_stripe_size = btrfs_stripe_nr_to_offset(nr_data_stripes(map));

-	buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
+	buf = kzalloc_objs(*buf, map->num_stripes, GFP_NOFS);
 	if (!buf) {
 		ret = -ENOMEM;
 		goto out;
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 02105d68accb..1ebfed8f0a0a 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -2110,8 +2110,8 @@ static int recover_sectors(struct btrfs_raid_bio *rbio)
 	 * @unmap_array stores copy of pointers that does not get reordered
 	 * during reconstruction so that kunmap_local works.
 	 */
-	pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
-	unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
+	pointers = kzalloc_objs(*pointers, rbio->real_stripes, GFP_NOFS);
+	unmap_array = kzalloc_objs(*unmap_array, rbio->real_stripes, GFP_NOFS);
 	if (!pointers || !unmap_array) {
 		ret = -ENOMEM;
 		goto out;
@@ -2844,8 +2844,8 @@ static int recover_scrub_rbio(struct btrfs_raid_bio *rbio)
 	 * @unmap_array stores copy of pointers that does not get reordered
 	 * during reconstruction so that kunmap_local works.
 	 */
-	pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
-	unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
+	pointers = kzalloc_objs(*pointers, rbio->real_stripes, GFP_NOFS);
+	unmap_array = kzalloc_objs(*unmap_array, rbio->real_stripes, GFP_NOFS);
 	if (!pointers || !unmap_array) {
 		ret = -ENOMEM;
 		goto out;
diff --git a/fs/btrfs/tests/zoned-tests.c b/fs/btrfs/tests/zoned-tests.c
index da21c7aea31a..2bc3b14baa41 100644
--- a/fs/btrfs/tests/zoned-tests.c
+++ b/fs/btrfs/tests/zoned-tests.c
@@ -58,7 +58,7 @@ static int test_load_zone_info(struct btrfs_fs_info *fs_info,
 		return -ENOMEM;
 	}

-	zone_info = kcalloc(test->num_stripes, sizeof(*zone_info), GFP_KERNEL);
+	zone_info = kzalloc_objs(*zone_info, test->num_stripes, GFP_KERNEL);
 	if (!zone_info) {
 		test_err("cannot allocate zone info");
 		return -ENOMEM;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e15e138c515b..c0cf8f7c5a8e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5499,8 +5499,7 @@ static int calc_one_profile_avail(struct btrfs_fs_info *fs_info,
 		goto out;
 	}

-	devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
-			       GFP_NOFS);
+	devices_info = kzalloc_objs(*devices_info, fs_devices->rw_devices, GFP_NOFS);
 	if (!devices_info) {
 		ret = -ENOMEM;
 		goto out;
@@ -6067,8 +6066,7 @@ struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans,
 	ctl.space_info = space_info;
 	init_alloc_chunk_ctl(fs_devices, &ctl);

-	devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
-			       GFP_NOFS);
+	devices_info = kzalloc_objs(*devices_info, fs_devices->rw_devices, GFP_NOFS);
 	if (!devices_info)
 		return ERR_PTR(-ENOMEM);

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index ab330ec957bc..851b0de7bed7 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1697,8 +1697,7 @@ static int btrfs_load_block_group_raid10(struct btrfs_block_group *bg,
 		return -EINVAL;
 	}

-	raid0_allocs = kcalloc(map->num_stripes / map->sub_stripes, sizeof(*raid0_allocs),
-			       GFP_NOFS);
+	raid0_allocs = kzalloc_objs(*raid0_allocs, map->num_stripes / map->sub_stripes, GFP_NOFS);
 	if (!raid0_allocs)
 		return -ENOMEM;

@@ -1916,7 +1915,7 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache, bool new)

 	cache->physical_map = map;

-	zone_info = kcalloc(map->num_stripes, sizeof(*zone_info), GFP_NOFS);
+	zone_info = kzalloc_objs(*zone_info, map->num_stripes, GFP_NOFS);
 	if (!zone_info) {
 		ret = -ENOMEM;
 		goto out;
--
2.53.0