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From 07fee7aba5472d0e65345146a68b4bd1a8b656c3 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 3 Mar 2022 14:19:02 +0300
Subject: [PATCH] bcache: use bvec_kmap_local in bio_csum
Git-commit: 07fee7aba5472d0e65345146a68b4bd1a8b656c3
Patch-mainline: v5.18-rc1
References: git-fixes

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>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20220303111905.321089-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.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 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);
-- 
2.35.3