From 11d83360452ea2a95e699da01f8e1bcc4676a5de Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Tue, 14 Apr 2015 15:48:21 -0700 Subject: [PATCH] mm, mempool: do not allow atomic resizing Allocating a large number of elements in atomic context could quickly deplete memory reserves, so just disallow atomic resizing entirely. Nothing currently uses mempool_resize() with anything other than GFP_KERNEL, so convert existing callers to drop the gfp_mask. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: David Rientjes Acked-by: Steffen Maier [zfcp] Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Steve French Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/s390/scsi/zfcp_erp.c | 4 ++-- fs/cifs/connect.c | 6 ++---- include/linux/mempool.h | 2 +- mm/mempool.c | 10 ++++++---- 4 files changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c index 2c5d4567d1da..acde3f5d6e9e 100644 --- a/drivers/s390/scsi/zfcp_erp.c +++ b/drivers/s390/scsi/zfcp_erp.c @@ -738,11 +738,11 @@ static int zfcp_erp_adapter_strategy_open_fsf(struct zfcp_erp_action *act) return ZFCP_ERP_FAILED; if (mempool_resize(act->adapter->pool.sr_data, - act->adapter->stat_read_buf_num, GFP_KERNEL)) + act->adapter->stat_read_buf_num)) return ZFCP_ERP_FAILED; if (mempool_resize(act->adapter->pool.status_read_req, - act->adapter->stat_read_buf_num, GFP_KERNEL)) + act->adapter->stat_read_buf_num)) return ZFCP_ERP_FAILED; atomic_set(&act->adapter->stat_miss, act->adapter->stat_read_buf_num); diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 480cf9c81d50..f3bfe08e177b 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -773,8 +773,7 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server) length = atomic_dec_return(&tcpSesAllocCount); if (length > 0) - mempool_resize(cifs_req_poolp, length + cifs_min_rcv, - GFP_KERNEL); + mempool_resize(cifs_req_poolp, length + cifs_min_rcv); } static int @@ -848,8 +847,7 @@ cifs_demultiplex_thread(void *p) length = atomic_inc_return(&tcpSesAllocCount); if (length > 1) - mempool_resize(cifs_req_poolp, length + cifs_min_rcv, - GFP_KERNEL); + mempool_resize(cifs_req_poolp, length + cifs_min_rcv); set_freezable(); while (server->tcpStatus != CifsExiting) { diff --git a/include/linux/mempool.h b/include/linux/mempool.h index 39ed62ab5b8a..b19b3023c880 100644 --- a/include/linux/mempool.h +++ b/include/linux/mempool.h @@ -29,7 +29,7 @@ extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn, mempool_free_t *free_fn, void *pool_data, gfp_t gfp_mask, int nid); -extern int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask); +extern int mempool_resize(mempool_t *pool, int new_min_nr); extern void mempool_destroy(mempool_t *pool); extern void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask); extern void mempool_free(void *element, mempool_t *pool); diff --git a/mm/mempool.c b/mm/mempool.c index e209c98c7203..949970db2874 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -113,23 +113,24 @@ EXPORT_SYMBOL(mempool_create_node); * mempool_create(). * @new_min_nr: the new minimum number of elements guaranteed to be * allocated for this pool. - * @gfp_mask: the usual allocation bitmask. * * This function shrinks/grows the pool. In the case of growing, * it cannot be guaranteed that the pool will be grown to the new * size immediately, but new mempool_free() calls will refill it. + * This function may sleep. * * Note, the caller must guarantee that no mempool_destroy is called * while this function is running. mempool_alloc() & mempool_free() * might be called (eg. from IRQ contexts) while this function executes. */ -int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask) +int mempool_resize(mempool_t *pool, int new_min_nr) { void *element; void **new_elements; unsigned long flags; BUG_ON(new_min_nr <= 0); + might_sleep(); spin_lock_irqsave(&pool->lock, flags); if (new_min_nr <= pool->min_nr) { @@ -145,7 +146,8 @@ int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask) spin_unlock_irqrestore(&pool->lock, flags); /* Grow the pool */ - new_elements = kmalloc(new_min_nr * sizeof(*new_elements), gfp_mask); + new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements), + GFP_KERNEL); if (!new_elements) return -ENOMEM; @@ -164,7 +166,7 @@ int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask) while (pool->curr_nr < pool->min_nr) { spin_unlock_irqrestore(&pool->lock, flags); - element = pool->alloc(gfp_mask, pool->pool_data); + element = pool->alloc(GFP_KERNEL, pool->pool_data); if (!element) goto out; spin_lock_irqsave(&pool->lock, flags); -- 2.20.1