hpfs: implement prefetch to improve performance

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / hpfs / map.c

diff --git a/fs/hpfs/map.c b/fs/hpfs/map.c
index 803d3da..3aa66ae 100644 (file)
--- a/fs/hpfs/map.c
+++ b/fs/hpfs/map.c
@@ -17,6 +17,7 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
                         struct quad_buffer_head *qbh, char *id)
 {
        secno sec;
+       __le32 *ret;
        unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
        if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
                hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
@@ -27,7 +28,23 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
                hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
                return NULL;
        }
-       return hpfs_map_4sectors(s, sec, qbh, 4);
+       ret = hpfs_map_4sectors(s, sec, qbh, 4);
+       if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
+       return ret;
+}
+
+void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
+{
+       unsigned to_prefetch, next_prefetch;
+       unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
+       if (unlikely(bmp_block >= n_bands))
+               return;
+       to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
+       if (unlikely(bmp_block + 1 >= n_bands))
+               next_prefetch = 0;
+       else
+               next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
+       hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
 }
 
 /*