| Message ID | 20190806001825.GA6854@embeddedor (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | dm raid1: Use struct_size() in kzalloc() | expand |
> +++ b/drivers/md/dm-raid1.c > @@ -878,12 +878,9 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors, > struct dm_target *ti, > struct dm_dirty_log *dl) > { > - size_t len; > struct mirror_set *ms = NULL; … How do you think about to replace the initialisation “NULL” by the desired function call? Regards, Markus -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index 5a51151f680d..f7226ab57fc8 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -878,12 +878,9 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors, struct dm_target *ti, struct dm_dirty_log *dl) { - size_t len; struct mirror_set *ms = NULL; - len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); - - ms = kzalloc(len, GFP_KERNEL); + ms = kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL); if (!ms) { ti->error = "Cannot allocate mirror context"; return NULL;
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 mirror_set { ... struct mirror mirror[0]; }; size = sizeof(struct mirror_set) + count * sizeof(struct mirror); instance = kzalloc(size, 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, mirror, count), GFP_KERNEL) Notice that, in this case, variable len is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/md/dm-raid1.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)