bcache: use bvec_kmap_local in bio_csum

Using local kmaps slightly reduces the chances to stray writes, and
the bvec interface cleans up the code a little bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 6869e010475a3dcf4b2107d6b3c838853799ec02..fdd0194f84dd089572f34cdcad1401c8748db9b0 100644 (file)
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -44,10 +44,10 @@ static void bio_csum(struct bio *bio, struct bkey *k)
        uint64_t csum = 0;
 
        bio_for_each_segment(bv, bio, iter) {
-               void *d = kmap(bv.bv_page) + bv.bv_offset;
+               void *d = bvec_kmap_local(&bv);
 
                csum = crc64_be(csum, d, bv.bv_len);
-               kunmap(bv.bv_page);
+               kunmap_local(d);
        }
 
        k->ptr[KEY_PTRS(k)] = csum & (~0ULL >> 1);