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Commit 14cb9538 authored by David Rientjes's avatar David Rientjes Committed by Alex Shi
Browse files

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: default avatarDavid Rientjes <rientjes@google.com>
Acked-by: Steffen Maier <maier@linux.vnet.ibm.com>	[zfcp]
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit 11d83360452ea2a95e699da01f8e1bcc4676a5de)
Signed-off-by: default avatarAlex Shi <alex.shi@linaro.org>
parent be8a0705

drivers/s390/scsi/zfcp_erp.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

fs/cifs/connect.c

+2 −4
Original line number Diff line number Diff line
@@ -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) {

include/linux/mempool.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

mm/mempool.c

+6 −4
Original line number Diff line number Diff line
@@ -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);