From 3a2b67e6e3fdb14c6da4c6909454d7a1d9b24f70 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 15 Dec 2020 20:43:04 -0800 Subject: lib/stackdepot.c: replace one-element array with flexible-array member MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "lib/stackdepot.c: Replace one-element array with flexible-array member". This series aims to replace a one-element array with a flexible-array member. Also, make use of the struct_size(), flexible_array_size() and array_size() helpers. This patch (of 3): There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Refactor the code according to the use of a flexible-array member in struct stack_record, instead of a one-element array, and use the struct_size() helper to calculate the size for the allocation. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays Link: https://lkml.kernel.org/r/cover.1601565471.git.gustavoars@kernel.org Link: https://lore.kernel.org/lkml/5f75876b.x9zdN10esiC0qLHV%25lkp@intel.com/ Link: https://lkml.kernel.org/r/2f1e6a17aaa891ad9c58817cf0a10b8ab8894f59.1601565471.git.gustavoars@kernel.org Signed-off-by: Gustavo A. R. Silva Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/stackdepot.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 2caffc64e4c8..c6106cfb7950 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -62,7 +62,7 @@ struct stack_record { u32 hash; /* Hash in the hastable */ u32 size; /* Number of frames in the stack */ union handle_parts handle; - unsigned long entries[1]; /* Variable-sized array of entries. */ + unsigned long entries[]; /* Variable-sized array of entries. */ }; static void *stack_slabs[STACK_ALLOC_MAX_SLABS]; @@ -104,9 +104,8 @@ static bool init_stack_slab(void **prealloc) static struct stack_record *depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc, gfp_t alloc_flags) { - int required_size = offsetof(struct stack_record, entries) + - sizeof(unsigned long) * size; struct stack_record *stack; + size_t required_size = struct_size(stack, entries, size); required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN); -- cgit v1.2.3