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authorGustavo A. R. Silva <gustavo@embeddedor.com>2019-03-05 15:41:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 21:07:13 -0800
commitf402cf03fc4c5576df379e1e252a6afc17658414 (patch)
tree4ab2a4841c2a371756deb49ec33aff600060c6be
parent5500ab4ed3b8f0749ec584d8c5e2738bc01ea52e (diff)
ocfs2: Use zero-sized array and struct_size() in kzalloc()
Update the code to use a zero-sized array instead of a pointer in structure ocfs2_slot_info and use struct_size() in kzalloc(). Notice that one of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Link: http://lkml.kernel.org/r/20190108191903.GA22056@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mark Fasheh <mfasheh@versity.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Joseph Qi <joseph.qi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/ocfs2/slot_map.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index d7407994f308..ea0756d83250 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -55,7 +55,7 @@ struct ocfs2_slot_info {
unsigned int si_blocks;
struct buffer_head **si_bh;
unsigned int si_num_slots;
- struct ocfs2_slot *si_slots;
+ struct ocfs2_slot si_slots[];
};
@@ -420,9 +420,7 @@ int ocfs2_init_slot_info(struct ocfs2_super *osb)
struct inode *inode = NULL;
struct ocfs2_slot_info *si;
- si = kzalloc(sizeof(struct ocfs2_slot_info) +
- (sizeof(struct ocfs2_slot) * osb->max_slots),
- GFP_KERNEL);
+ si = kzalloc(struct_size(si, si_slots, osb->max_slots), GFP_KERNEL);
if (!si) {
status = -ENOMEM;
mlog_errno(status);
@@ -431,8 +429,6 @@ int ocfs2_init_slot_info(struct ocfs2_super *osb)
si->si_extended = ocfs2_uses_extended_slot_map(osb);
si->si_num_slots = osb->max_slots;
- si->si_slots = (struct ocfs2_slot *)((char *)si +
- sizeof(struct ocfs2_slot_info));
inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
OCFS2_INVALID_SLOT);