btrfs: scrub: clean up temporary page variables in scrub_checksum_tree_block

Add proper variable for the scrub page and use it instead of repeatedly
dereferencing the other structures.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 663bb2c..d935ac0 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1816,12 +1816,12 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock)
        u8 on_disk_csum[BTRFS_CSUM_SIZE];
        const int num_pages = sctx->fs_info->nodesize >> PAGE_SHIFT;
        int i;
-       struct page *page;
+       struct scrub_page *spage;
        char *kaddr;
 
        BUG_ON(sblock->page_count < 1);
-       page = sblock->pagev[0]->page;
-       kaddr = page_address(page);
+       spage = sblock->pagev[0];
+       kaddr = page_address(spage->page);
        h = (struct btrfs_header *)kaddr;
        memcpy(on_disk_csum, h->csum, sctx->csum_size);
 
@@ -1830,15 +1830,15 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock)
         * a) don't have an extent buffer and
         * b) the page is already kmapped
         */
-       if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
+       if (spage->logical != btrfs_stack_header_bytenr(h))
                sblock->header_error = 1;
 
-       if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) {
+       if (spage->generation != btrfs_stack_header_generation(h)) {
                sblock->header_error = 1;
                sblock->generation_error = 1;
        }
 
-       if (!scrub_check_fsid(h->fsid, sblock->pagev[0]))
+       if (!scrub_check_fsid(h->fsid, spage))
                sblock->header_error = 1;
 
        if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,