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Commit a822c83e authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin: allocate the cell_sort_array dynamically 



Given the pool's cell_sort_array holds 8192 pointers it triggers an
order 5 allocation via kmalloc.  This order 5 allocation is prone to
failure as system memory gets more fragmented over time.

Fix this by allocating the cell_sort_array using vmalloc.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
parent 4c7e3093

drivers/md/dm-thin.c

+12 −1
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/init.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/sort.h>

#include <linux/rbtree.h>
@@ -268,7 +269,7 @@ struct pool { 
	process_mapping_fn process_prepared_mapping;

	process_mapping_fn process_prepared_discard;



	struct dm_bio_prison_cell *cell_sort_array[CELL_SORT_ARRAY_SIZE];

	struct dm_bio_prison_cell **cell_sort_array;

};



static enum pool_mode get_pool_mode(struct pool *pool);
@@ -2777,6 +2778,7 @@ static void __pool_destroy(struct pool *pool) 
{

	__pool_table_remove(pool);



	vfree(pool->cell_sort_array);

	if (dm_pool_metadata_close(pool->pmd) < 0)

		DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
@@ -2889,6 +2891,13 @@ static struct pool *pool_create(struct mapped_device *pool_md, 
		goto bad_mapping_pool;

	}



	pool->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE);

	if (!pool->cell_sort_array) {

		*error = "Error allocating cell sort array";

		err_p = ERR_PTR(-ENOMEM);

		goto bad_sort_array;

	}



	pool->ref_count = 1;

	pool->last_commit_jiffies = jiffies;

	pool->pool_md = pool_md;
@@ -2897,6 +2906,8 @@ static struct pool *pool_create(struct mapped_device *pool_md, 


	return pool;



bad_sort_array:

	mempool_destroy(pool->mapping_pool);

bad_mapping_pool:

	dm_deferred_set_destroy(pool->all_io_ds);

bad_all_io_ds: