aoe: use bvec_kmap_local in bvcpy

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>
Link: https://lore.kernel.org/r/20220303111905.321089-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

drivers/block/aoe/aoecmd.c

@@ -1018,9 +1018,9 @@ bvcpy(struct sk_buff *skb, struct bio *bio, struct bvec_iter iter, long cnt)
 	iter.bi_size = cnt;
 
 	__bio_for_each_segment(bv, bio, iter, iter) {
-		char *p = kmap_atomic(bv.bv_page) + bv.bv_offset;
+		char *p = bvec_kmap_local(&bv);
 		skb_copy_bits(skb, soff, p, bv.bv_len);
-		kunmap_atomic(p);
+		kunmap_local(p);
 		soff += bv.bv_len;
 	}
 }