From: Christoph Hellwig <hch@lst.de>
Date: Thu, 20 May 2021 13:10:45 +0000 (+0200)
Subject: bcache: use bvec_kmap_local in bio_csum
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=659ae98fc89c29165f855f46d80414a277610855;p=users%2Fhch%2Fblock.git

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 6869e010475a..fdd0194f84dd 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);