[dm-devel] [dm-6.4 PATCH v3 20/20] dm bio prison v1: intelligently size dm_bio_prison's prison_regions

Mike Snitzer
2023-03-27T20:14:09Z

Size the dm_bio_prison's number of prison_region structs using
dm_num_sharded_locks().

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
drivers/md/dm-bio-prison-v1.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-bio-prison-v1.c b/drivers/md/dm-bio-prison-v1.c
index a7930ad1878b..1d560a83b144 100644
--- a/drivers/md/dm-bio-prison-v1.c
+++ b/drivers/md/dm-bio-prison-v1.c
@@ -16,7 +16,6 @@

/*----------------------------------------------------------------*/

-#define NR_LOCKS 64
#define MIN_CELLS 1024

struct prison_region {
@@ -27,7 +26,7 @@ struct prison_region {
struct dm_bio_prison {
mempool_t cell_pool;
unsigned int num_locks;
- struct prison_region regions[NR_LOCKS];
+ struct prison_region regions[];
};

static struct kmem_cache *_cell_cache;
@@ -41,12 +40,14 @@ static struct kmem_cache *_cell_cache;
struct dm_bio_prison *dm_bio_prison_create(void)
{
int ret;
- unsigned i;
- struct dm_bio_prison *prison = kzalloc(sizeof(*prison), GFP_KERNEL);
+ unsigned int i, num_locks;
+ struct dm_bio_prison *prison;

+ num_locks = dm_num_sharded_locks();
+ prison = kzalloc(struct_size(prison, regions, num_locks), GFP_KERNEL);
if (!prison)
return NULL;
- prison->num_locks = NR_LOCKS;
+ prison->num_locks = num_locks;

for (i = 0; i < prison->num_locks; i++) {
spin_lock_init(&prison->regions[i].lock);