3.2.71-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Joe Thornber <e...@redhat.com>
commit a822c83e47d97cdef38c4352e1ef62d9f46cfe98 upstream.
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: Joe Thornber <e...@redhat.com>
Signed-off-by: Mike Snitzer <snit...@redhat.com>
[bwh: Backported to 3.2: make a similar change in prison_{create,destroy}()]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
drivers/md/dm-thin.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -13,6 +13,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#define DM_MSG_PREFIX "thin"
@@ -158,9 +159,7 @@ static struct bio_prison *prison_create(
{
unsigned i;
uint32_t nr_buckets = calc_nr_buckets(nr_cells);
- size_t len = sizeof(struct bio_prison) +
- (sizeof(struct hlist_head) * nr_buckets);
- struct bio_prison *prison = kmalloc(len, GFP_KERNEL);
+ struct bio_prison *prison = kmalloc(sizeof(*prison), GFP_KERNEL);
if (!prison)
return NULL;
@@ -173,9 +172,15 @@ static struct bio_prison *prison_create(
return NULL;
}
+ prison->cells = vmalloc(sizeof(*prison->cells) * nr_buckets);
+ if (!prison->cells) {
+ mempool_destroy(prison->cell_pool);
+ kfree(prison);
+ return NULL;
+ }
+
prison->nr_buckets = nr_buckets;
prison->hash_mask = nr_buckets - 1;
- prison->cells = (struct hlist_head *) (prison + 1);
for (i = 0; i < nr_buckets; i++)
INIT_HLIST_HEAD(prison->cells + i);
@@ -184,6 +189,7 @@ static struct bio_prison *prison_create(
static void prison_destroy(struct bio_prison *prison)
{
+ vfree(prison->cells);
mempool_destroy(prison->cell_pool);
kfree(prison);
}
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