[PATCH] btrfs: Use kvzalloc instead of kzalloc/vmalloc in alloc_bitmap

[Vinnie Magro]

Replace alloc_bitmap with call to kvzalloc. kvzalloc preserves the
same fallback heuristic.

Signed-off-by: Vinnie Magro <vma...@fb.com>
---
 fs/btrfs/free-space-tree.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index fc0bd84..9e87129 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -151,25 +151,6 @@ static inline u32 free_space_bitmap_size(u64 size, u32 
sectorsize)
        return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
 }
 
-static u8 *alloc_bitmap(u32 bitmap_size)
-{
-       void *mem;
-
-       /*
-        * The allocation size varies, observed numbers were < 4K up to 16K.
-        * Using vmalloc unconditionally would be too heavy, we'll try
-        * contiguous allocations first.
-        */
-       if  (bitmap_size <= PAGE_SIZE)
-               return kzalloc(bitmap_size, GFP_NOFS);
-
-       mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN);
-       if (mem)
-               return mem;
-
-       return __vmalloc(bitmap_size, GFP_NOFS | __GFP_ZERO, PAGE_KERNEL);
-}
-
 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
                                  struct btrfs_fs_info *fs_info,
                                  struct btrfs_block_group_cache *block_group,
@@ -189,7 +170,7 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle 
*trans,
 
        bitmap_size = free_space_bitmap_size(block_group->key.offset,
                                             fs_info->sectorsize);
-       bitmap = alloc_bitmap(bitmap_size);
+       bitmap = kvzalloc(bitmap_size, GFP_NOFS);
        if (!bitmap) {
                ret = -ENOMEM;
                goto out;
@@ -330,7 +311,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle 
*trans,
 
        bitmap_size = free_space_bitmap_size(block_group->key.offset,
                                             fs_info->sectorsize);
-       bitmap = alloc_bitmap(bitmap_size);
+       bitmap = kvzalloc(bitmap_size, GFP_NOFS);
        if (!bitmap) {
                ret = -ENOMEM;
                goto out;
-- 
2.9.3