btrfs: scrub: clean up temporary page variables in scrub_checksum_data

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 16c8313..19a64c7 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1786,23 +1786,21 @@ static int scrub_checksum_data(struct scrub_block *sblock)
        struct btrfs_fs_info *fs_info = sctx->fs_info;
        SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
        u8 csum[BTRFS_CSUM_SIZE];
-       u8 *on_disk_csum;
-       struct page *page;
+       struct scrub_page *spage;
        char *kaddr;
 
        BUG_ON(sblock->page_count < 1);
-       if (!sblock->pagev[0]->have_csum)
+       spage = sblock->pagev[0];
+       if (!spage->have_csum)
                return 0;
 
-       on_disk_csum = sblock->pagev[0]->csum;
-       page = sblock->pagev[0]->page;
-       kaddr = page_address(page);
+       kaddr = page_address(spage->page);
 
        shash->tfm = fs_info->csum_shash;
        crypto_shash_init(shash);
        crypto_shash_digest(shash, kaddr, PAGE_SIZE, csum);
 
-       if (memcmp(csum, on_disk_csum, sctx->csum_size))
+       if (memcmp(csum, spage->csum, sctx->csum_size))
                sblock->checksum_error = 1;
 
        return sblock->checksum_error;