Fix pcpu_alloc() to return ZERO_SIZE_PTR if requested size is 0; fix free_percpu() to check passed pointer with ZERO_OR_NULL_PTR.
Signed-off-by: Dmitry Antipov dmitry.antipov@linaro.org --- mm/percpu.c | 16 +++++++++++----- 1 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/mm/percpu.c b/mm/percpu.c index f47af91..e903a19 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -702,7 +702,8 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) * Does GFP_KERNEL allocation. * * RETURNS: - * Percpu pointer to the allocated area on success, NULL on failure. + * ZERO_SIZE_PTR if @size is zero, percpu pointer to the + * allocated area on success or NULL on failure. */ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) { @@ -713,7 +714,10 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) unsigned long flags; void __percpu *ptr;
- if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { + if (unlikely(!size)) + return ZERO_SIZE_PTR; + + if (unlikely(size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { WARN(true, "illegal size (%zu) or align (%zu) for " "percpu allocation\n", size, align); return NULL; @@ -834,7 +838,8 @@ fail_unlock_mutex: * Does GFP_KERNEL allocation. * * RETURNS: - * Percpu pointer to the allocated area on success, NULL on failure. + * ZERO_SIZE_PTR if @size is zero, percpu pointer to the + * allocated area on success, NULL on failure. */ void __percpu *__alloc_percpu(size_t size, size_t align) { @@ -856,7 +861,8 @@ EXPORT_SYMBOL_GPL(__alloc_percpu); * Does GFP_KERNEL allocation. * * RETURNS: - * Percpu pointer to the allocated area on success, NULL on failure. + * ZERO_SIZE_PTR if @size is zero, percpu pointer to the + * allocated area on success or NULL on failure. */ void __percpu *__alloc_reserved_percpu(size_t size, size_t align) { @@ -917,7 +923,7 @@ void free_percpu(void __percpu *ptr) unsigned long flags; int off;
- if (!ptr) + if (unlikely(ZERO_OR_NULL_PTR(ptr))) return;
kmemleak_free_percpu(ptr);