iss-simdisk: use bvec_kmap_local in simdisk_submit_bio

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>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Link: https://lore.kernel.org/r/20220303111905.321089-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

arch/xtensa/platforms/iss/simdisk.c

@@ -108,13 +108,13 @@ static void simdisk_submit_bio(struct bio *bio)
 	sector_t sector = bio->bi_iter.bi_sector;
 
 	bio_for_each_segment(bvec, bio, iter) {
-		char *buffer = kmap_atomic(bvec.bv_page) + bvec.bv_offset;
+		char *buffer = bvec_kmap_local(&bvec);
 		unsigned len = bvec.bv_len >> SECTOR_SHIFT;
 
 		simdisk_transfer(dev, sector, len, buffer,
 				bio_data_dir(bio) == WRITE);
 		sector += len;
-		kunmap_atomic(buffer);
+		kunmap_local(buffer);
 	}
 
 	bio_endio(bio);