btrfs: reada: Pass reada_extent into __readahead_hook directly

reada_start_machine_dev() already have reada_extent pointer, pass
it into __readahead_hook() directly instead of search radix_tree
will make code run faster.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 24 insertions, 21 deletions

diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index f7642e569bd9..203bec4823e1 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -105,33 +105,21 @@ static int reada_add_block(struct reada_control *rc, u64 logical,
 
 /* recurses */
 /* in case of err, eb might be NULL */
-static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
-                            u64 start, int err)
+static void __readahead_hook(struct btrfs_root *root, struct reada_extent *re,
+                             struct extent_buffer *eb, u64 start, int err)
 {
         int level = 0;
         int nritems;
         int i;
         u64 bytenr;
         u64 generation;
-        struct reada_extent *re;
         struct btrfs_fs_info *fs_info = root->fs_info;
         struct list_head list;
-        unsigned long index = start >> PAGE_CACHE_SHIFT;
         struct btrfs_device *for_dev;
 
         if (eb)
                 level = btrfs_header_level(eb);
 
-        /* find extent */
-        spin_lock(&fs_info->reada_lock);
-        re = radix_tree_lookup(&fs_info->reada_tree, index);
-        if (re)
-                re->refcnt++;
-        spin_unlock(&fs_info->reada_lock);
-
-        if (!re)
-                return -1;
-
         spin_lock(&re->lock);
         /*
          * just take the full list from the extent. afterwards we
@@ -221,11 +209,11 @@ static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
 
                 reada_extent_put(fs_info, re);  /* one ref for each entry */
         }
-        reada_extent_put(fs_info, re);  /* our ref */
+
         if (for_dev)
                 atomic_dec(&for_dev->reada_in_flight);
 
-        return 0;
+        return;
 }
 
 /*
@@ -235,12 +223,27 @@ static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
 int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
                          u64 start, int err)
 {
-        int ret;
+        int ret = 0;
+        struct reada_extent *re;
+        struct btrfs_fs_info *fs_info = root->fs_info;
 
-        ret = __readahead_hook(root, eb, start, err);
+        /* find extent */
+        spin_lock(&fs_info->reada_lock);
+        re = radix_tree_lookup(&fs_info->reada_tree,
+                               start >> PAGE_CACHE_SHIFT);
+        if (re)
+                re->refcnt++;
+        spin_unlock(&fs_info->reada_lock);
+        if (!re) {
+                ret = -1;
+                goto start_machine;
+        }
 
-        reada_start_machine(root->fs_info);
+        __readahead_hook(fs_info, re, eb, start, err);
+        reada_extent_put(fs_info, re);  /* our ref */
 
+start_machine:
+        reada_start_machine(fs_info);
         return ret;
 }
 
@@ -721,9 +724,9 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
         ret = reada_tree_block_flagged(fs_info->extent_root, logical,
                         mirror_num, &eb);
         if (ret)
-                __readahead_hook(fs_info->extent_root, NULL, logical, ret);
+                __readahead_hook(fs_info->extent_root, re, NULL, logical, ret);
         else if (eb)
-                __readahead_hook(fs_info->extent_root, eb, eb->start, ret);
+                __readahead_hook(fs_info->extent_root, re, eb, eb->start, ret);
 
         if (eb)
                 free_extent_buffer(eb);