We need limit the maximum size of queue, otherwise it may cause several side effects e.g slab will warn when the size exceeds KMALLOC_MAX_SIZE. Using KMALLOC_MAX_SIZE still looks too so this patch tries to limit it to 64K. This value could be revisited if we found a real case that needs more.
Reported-by: [email protected] Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") Signed-off-by: Jason Wang <[email protected]> --- include/linux/ptr_ring.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h index 2af71a7..5858d48 100644 --- a/include/linux/ptr_ring.h +++ b/include/linux/ptr_ring.h @@ -44,6 +44,8 @@ struct ptr_ring { void **queue; }; +#define PTR_RING_MAX_ALLOC 65536 + /* Note: callers invoking this in a loop must use a compiler barrier, * for example cpu_relax(). * @@ -466,6 +468,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r, static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp) { + if (size > PTR_RING_MAX_ALLOC) + return NULL; return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO); } -- 2.7.4
