dm bufio: reorder fields in dm_buffer structure

Reorder fields in dm_buffer structure to improve packing and reduce
structure size.  The compiler allocates 32-bit integer for field 'enum
data_mode', so change it to unsigned char.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index c57aefb3c6438dcfbbe5f2bdfc8dfba21a4fda31..776075ccf775d9d9896e9bfcb36bf02527e76a8a 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -147,11 +147,11 @@ struct dm_buffer {
        struct list_head lru_list;
        sector_t block;
        void *data;
-       enum data_mode data_mode;
+       unsigned char data_mode;                /* DATA_MODE_* */
        unsigned char list_mode;                /* LIST_* */
-       unsigned hold_count;
        blk_status_t read_error;
        blk_status_t write_error;
+       unsigned hold_count;
        unsigned long state;
        unsigned long last_accessed;
        unsigned dirty_start;
@@ -303,7 +303,7 @@ static void __remove(struct dm_bufio_client *c, struct dm_buffer *b)
 
 /*----------------------------------------------------------------*/
 
-static void adjust_total_allocated(enum data_mode data_mode, long diff)
+static void adjust_total_allocated(unsigned char data_mode, long diff)
 {
        static unsigned long * const class_ptr[DATA_MODE_LIMIT] = {
                &dm_bufio_allocated_kmem_cache,
@@ -368,7 +368,7 @@ static void __cache_size_refresh(void)
  * space.
  */
 static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
-                              enum data_mode *data_mode)
+                              unsigned char *data_mode)
 {
        if (unlikely(c->slab_cache != NULL)) {
                *data_mode = DATA_MODE_SLAB;
@@ -408,7 +408,7 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
  * Free buffer's data.
  */
 static void free_buffer_data(struct dm_bufio_client *c,
-                            void *data, enum data_mode data_mode)
+                            void *data, unsigned char data_mode)
 {
        switch (data_mode) {
        case DATA_MODE_SLAB: