The patch titled flex_array: introduce DEFINE_FLEX_ARRAY has been removed from the -mm tree. Its filename was flex_array-introduce-define_flex_array.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: flex_array: introduce DEFINE_FLEX_ARRAY From: David Rientjes <rientjes@xxxxxxxxxx> FLEX_ARRAY_INIT(element_size, total_nr_elements) cannot determine if either parameter is valid, so flex arrays which are statically allocated with this interface can easily become corrupted or reference beyond its allocated memory. This removes FLEX_ARRAY_INIT() as a struct flex_array initializer since no initializer may perform the required checking. Instead, the array is now defined with a new interface: DEFINE_FLEX_ARRAY(name, element_size, total_nr_elements) This may be prefixed with `static' for file scope. This interface includes compile-time checking of the parameters to ensure they are valid. Since the validity of both element_size and total_nr_elements depend on FLEX_ARRAY_BASE_SIZE and FLEX_ARRAY_PART_SIZE, the kernel build will fail if either of these predefined values changes such that the array parameters are no longer valid. Since BUILD_BUG_ON() requires compile time constants, several of the static inline functions that were once local to lib/flex_array.c had to be moved to include/linux/flex_array.h. Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> Acked-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/flex_array.h | 30 +++++++++++++++++++++++++---- lib/flex_array.c | 36 +++++++++-------------------------- 2 files changed, 36 insertions(+), 30 deletions(-) diff -puN include/linux/flex_array.h~flex_array-introduce-define_flex_array include/linux/flex_array.h --- a/include/linux/flex_array.h~flex_array-introduce-define_flex_array +++ a/include/linux/flex_array.h @@ -31,10 +31,32 @@ struct flex_array { }; }; -#define FLEX_ARRAY_INIT(size, total) { { {\ - .element_size = (size), \ - .total_nr_elements = (total), \ -} } } +/* Number of bytes left in base struct flex_array, excluding metadata */ +#define FLEX_ARRAY_BASE_BYTES_LEFT \ + (FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts)) + +/* Number of pointers in base to struct flex_array_part pages */ +#define FLEX_ARRAY_NR_BASE_PTRS \ + (FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *)) + +/* Number of elements of size that fit in struct flex_array_part */ +#define FLEX_ARRAY_ELEMENTS_PER_PART(size) \ + (FLEX_ARRAY_PART_SIZE / size) + +/* + * Defines a statically allocated flex array and ensures its parameters are + * valid. + */ +#define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \ + struct flex_array __arrayname = { { { \ + .element_size = (__element_size), \ + .total_nr_elements = (__total), \ + } } }; \ + static inline void __arrayname##_invalid_parameter(void) \ + { \ + BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \ + FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \ + } struct flex_array *flex_array_alloc(int element_size, unsigned int total, gfp_t flags); diff -puN lib/flex_array.c~flex_array-introduce-define_flex_array lib/flex_array.c --- a/lib/flex_array.c~flex_array-introduce-define_flex_array +++ a/lib/flex_array.c @@ -28,23 +28,6 @@ struct flex_array_part { char elements[FLEX_ARRAY_PART_SIZE]; }; -static inline int __elements_per_part(int element_size) -{ - return FLEX_ARRAY_PART_SIZE / element_size; -} - -static inline int bytes_left_in_base(void) -{ - int element_offset = offsetof(struct flex_array, parts); - int bytes_left = FLEX_ARRAY_BASE_SIZE - element_offset; - return bytes_left; -} - -static inline int nr_base_part_ptrs(void) -{ - return bytes_left_in_base() / sizeof(struct flex_array_part *); -} - /* * If a user requests an allocation which is small * enough, we may simply use the space in the @@ -54,7 +37,7 @@ static inline int nr_base_part_ptrs(void static inline int elements_fit_in_base(struct flex_array *fa) { int data_size = fa->element_size * fa->total_nr_elements; - if (data_size <= bytes_left_in_base()) + if (data_size <= FLEX_ARRAY_BASE_BYTES_LEFT) return 1; return 0; } @@ -103,7 +86,8 @@ struct flex_array *flex_array_alloc(int gfp_t flags) { struct flex_array *ret; - int max_size = nr_base_part_ptrs() * __elements_per_part(element_size); + int max_size = FLEX_ARRAY_NR_BASE_PTRS * + FLEX_ARRAY_ELEMENTS_PER_PART(element_size); /* max_size will end up 0 if element_size > PAGE_SIZE */ if (total > max_size) @@ -114,14 +98,15 @@ struct flex_array *flex_array_alloc(int ret->element_size = element_size; ret->total_nr_elements = total; if (elements_fit_in_base(ret) && !(flags & __GFP_ZERO)) - memset(ret->parts[0], FLEX_ARRAY_FREE, bytes_left_in_base()); + memset(ret->parts[0], FLEX_ARRAY_FREE, + FLEX_ARRAY_BASE_BYTES_LEFT); return ret; } static int fa_element_to_part_nr(struct flex_array *fa, unsigned int element_nr) { - return element_nr / __elements_per_part(fa->element_size); + return element_nr / FLEX_ARRAY_ELEMENTS_PER_PART(fa->element_size); } /** @@ -133,11 +118,10 @@ static int fa_element_to_part_nr(struct void flex_array_free_parts(struct flex_array *fa) { int part_nr; - int max_part = nr_base_part_ptrs(); if (elements_fit_in_base(fa)) return; - for (part_nr = 0; part_nr < max_part; part_nr++) + for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) kfree(fa->parts[part_nr]); } @@ -152,7 +136,8 @@ static unsigned int index_inside_part(st { unsigned int part_offset; - part_offset = element_nr % __elements_per_part(fa->element_size); + part_offset = element_nr % + FLEX_ARRAY_ELEMENTS_PER_PART(fa->element_size); return part_offset * fa->element_size; } @@ -313,13 +298,12 @@ static int part_is_free(struct flex_arra int flex_array_shrink(struct flex_array *fa) { struct flex_array_part *part; - int max_part = nr_base_part_ptrs(); int part_nr; int ret = 0; if (elements_fit_in_base(fa)) return ret; - for (part_nr = 0; part_nr < max_part; part_nr++) { + for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) { part = fa->parts[part_nr]; if (!part) continue; _ Patches currently in -mm which might be from rientjes@xxxxxxxxxx are origin.patch linux-next.patch x86-default-pcibus-cpumask-to-all-cpus-if-it-lacks-affinity.patch fs-proc-task_mmuc-v1-fix-clear_refs_write-input-sanity-check.patch walk-system-ram-range-fix-2.patch do_wait-optimization-do-not-place-sub-threads-on-task_struct-children-list.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html