btrfs-progs: Cleanup unneeded extra variant in btrfs_read_sys_array

The btrfs_read_sys_array function uses 3 variants to read data from
super block.

But the three variants are related to each other, so the patch removes
unneeded extra variants and make code a little simpler.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/volumes.c b/volumes.c
index cb7adef..68b4294 100644 (file)
--- a/volumes.c
+++ b/volumes.c
@@ -1645,11 +1645,9 @@ int btrfs_read_sys_array(struct btrfs_root *root)
        struct btrfs_chunk *chunk;
        struct btrfs_key key;
        u32 num_stripes;
-       u32 array_size;
        u32 len = 0;
        u8 *ptr;
-       unsigned long sb_ptr;
-       u32 cur;
+       u8 *array_end;
        int ret = 0;
 
        sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
@@ -1658,7 +1656,8 @@ int btrfs_read_sys_array(struct btrfs_root *root)
                return -ENOMEM;
        btrfs_set_buffer_uptodate(sb);
        write_extent_buffer(sb, super_copy, 0, sizeof(*super_copy));
-       array_size = btrfs_super_sys_array_size(super_copy);
+       array_end = ((u8 *)super_copy->sys_chunk_array) +
+                   btrfs_super_sys_array_size(super_copy);
 
        /*
         * we do this loop twice, once for the device items and
@@ -1666,20 +1665,16 @@ int btrfs_read_sys_array(struct btrfs_root *root)
         * structs filled in for every chunk
         */
        ptr = super_copy->sys_chunk_array;
-       sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
-       cur = 0;
 
-       while (cur < array_size) {
+       while (ptr < array_end) {
                disk_key = (struct btrfs_disk_key *)ptr;
                btrfs_disk_key_to_cpu(&key, disk_key);
 
                len = sizeof(*disk_key);
                ptr += len;
-               sb_ptr += len;
-               cur += len;
 
                if (key.type == BTRFS_CHUNK_ITEM_KEY) {
-                       chunk = (struct btrfs_chunk *)sb_ptr;
+                       chunk = (struct btrfs_chunk *)(ptr - (u8 *)super_copy);
                        ret = read_one_chunk(root, &key, sb, chunk);
                        if (ret)
                                break;
@@ -1689,8 +1684,6 @@ int btrfs_read_sys_array(struct btrfs_root *root)
                        BUG();
                }
                ptr += len;
-               sb_ptr += len;
-               cur += len;
        }
        free_extent_buffer(sb);
        return ret;