fs: btrfs: Use LZO_LEN to replace immediate number

Just a cleanup. These immediate numbers make my eyes hurt.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Cc: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Marek Behún <marek.behun@nic.cz>

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 346875d45a1be3761cbd749d168f1d9a44979149..4ef44ce11485d3375b461c33aa0fc68fb82c43e3 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -12,36 +12,38 @@
 #include <u-boot/zlib.h>
 #include <asm/unaligned.h>
 
+/* Header for each segment, LE32, recording the compressed size */
+#define LZO_LEN                4
 static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
 {
        u32 tot_len, in_len, res;
        size_t out_len;
        int ret;
 
-       if (clen < 4)
+       if (clen < LZO_LEN)
                return -1;
 
        tot_len = le32_to_cpu(get_unaligned((u32 *)cbuf));
-       cbuf += 4;
-       clen -= 4;
-       tot_len -= 4;
+       cbuf += LZO_LEN;
+       clen -= LZO_LEN;
+       tot_len -= LZO_LEN;
 
        if (tot_len == 0 && dlen)
                return -1;
-       if (tot_len < 4)
+       if (tot_len < LZO_LEN)
                return -1;
 
        res = 0;
 
-       while (tot_len > 4) {
+       while (tot_len > LZO_LEN) {
                in_len = le32_to_cpu(get_unaligned((u32 *)cbuf));
-               cbuf += 4;
-               clen -= 4;
+               cbuf += LZO_LEN;
+               clen -= LZO_LEN;
 
-               if (in_len > clen || tot_len < 4 + in_len)
+               if (in_len > clen || tot_len < LZO_LEN + in_len)
                        return -1;
 
-               tot_len -= 4 + in_len;
+               tot_len -= (LZO_LEN + in_len);
 
                out_len = dlen;
                ret = lzo1x_decompress_safe(cbuf, in_len, dbuf, &out_len);