f2fs: add a slab cache entry for small discards

This patch adds a slab cache entry for small discards.

Each entry consists of:

struct discard_entry {
	struct list_head list;	/* list head */
	block_t blkaddr;	/* block address to be discarded */
	int len;		/* # of consecutive blocks of the discard */
};

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 67f1e5bbdac9..823526ec5243 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -22,6 +22,8 @@
 
 #define __reverse_ffz(x) __reverse_ffs(~(x))
 
+static struct kmem_cache *discard_entry_slab;
+
 /*
  * __reverse_ffs is copied from include/asm-generic/bitops/__ffs.h since
  * MSB and LSB are reversed in a byte by f2fs_set_bit.
@@ -1798,6 +1800,10 @@ int build_segment_manager(struct f2fs_sb_info *sbi)
         sm_info->ssa_blkaddr = le32_to_cpu(raw_super->ssa_blkaddr);
         sm_info->rec_prefree_segments = DEF_RECLAIM_PREFREE_SEGMENTS;
 
+        INIT_LIST_HEAD(&sm_info->discard_list);
+        sm_info->nr_discards = 0;
+        sm_info->max_discards = 0;
+
         err = build_sit_info(sbi);
         if (err)
                 return err;
@@ -1913,3 +1919,17 @@ void destroy_segment_manager(struct f2fs_sb_info *sbi)
         sbi->sm_info = NULL;
         kfree(sm_info);
 }
+
+int __init create_segment_manager_caches(void)
+{
+        discard_entry_slab = f2fs_kmem_cache_create("discard_entry",
+                        sizeof(struct discard_entry), NULL);
+        if (!discard_entry_slab)
+                return -ENOMEM;
+        return 0;
+}
+
+void destroy_segment_manager_caches(void)
+{
+        kmem_cache_destroy(discard_entry_slab);
+}