From: Gustavo A. R. Silva Date: Tue, 5 Mar 2019 23:49:31 +0000 (-0800) Subject: mm/swapfile.c: use struct_size() in kvzalloc() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=960087445cd263c30ecc32b9e218887a349597ce;p=linux.git mm/swapfile.c: use struct_size() in kvzalloc() 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; struct boo entry[]; }; size = sizeof(struct foo) + count * sizeof(struct boo); instance = kvzalloc(size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kvzalloc(struct_size(instance, entry, count), GFP_KERNEL); Notice that, in this case, variable size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Link: http://lkml.kernel.org/r/20190221154622.GA19599@embeddedor Signed-off-by: Gustavo A. R. Silva Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/swapfile.c b/mm/swapfile.c index a14257ac0476c..2b8d9c3fbb47f 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2713,9 +2713,8 @@ static struct swap_info_struct *alloc_swap_info(void) struct swap_info_struct *p; unsigned int type; int i; - unsigned int size = sizeof(*p) + nr_node_ids * sizeof(struct plist_node); - p = kvzalloc(size, GFP_KERNEL); + p = kvzalloc(struct_size(p, avail_lists, nr_node_ids), GFP_KERNEL); if (!p) return ERR_PTR(-ENOMEM);