[PATCH 07/10] bcache: use bvec_kmap_local in bio_csum

Christoph Hellwig
2022-03-03T11:20:13Z

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>
---
drivers/md/bcache/request.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 6869e010475a3..fdd0194f84dd0 100644
--- 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);
--
2.30.2