linux-kernel - [PATCH 16/16] block: use bvec_kmap_local in bio_integrity

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Date:   Tue,  8 Jun 2021 18:06:03 +0200
From:   Christoph Hellwig <hch@....de>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Geoff Levand <geoff@...radead.org>,
        Ilya Dryomov <idryomov@...il.com>,
        Dongsheng Yang <dongsheng.yang@...ystack.cn>,
        Mike Snitzer <snitzer@...hat.com>,
        Ira Weiny <ira.weiny@...el.com>, dm-devel@...hat.com,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        ceph-devel@...r.kernel.org
Subject: [PATCH 16/16] block: use bvec_kmap_local in bio_integrity_process

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@....de>
---
 block/bio-integrity.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 4b4eb8964a6f..8f54d49dc500 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -172,18 +172,16 @@ static blk_status_t bio_integrity_process(struct bio *bio,
 	iter.prot_buf = prot_buf;
 
 	__bio_for_each_segment(bv, bio, bviter, *proc_iter) {
-		void *kaddr = kmap_atomic(bv.bv_page);
+		void *kaddr = bvec_kmap_local(&bv);
 
-		iter.data_buf = kaddr + bv.bv_offset;
+		iter.data_buf = kaddr;
 		iter.data_size = bv.bv_len;
-
 		ret = proc_fn(&iter);
-		if (ret) {
-			kunmap_atomic(kaddr);
-			return ret;
-		}
+		kunmap_local(kaddr);
+
+		if (ret)
+			break;
 
-		kunmap_atomic(kaddr);
 	}
 	return ret;
 }
-- 
2.30.2