Commit 18a6234c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

dm-writecache: use bvec_kmap_local instead of bvec_kmap_irq 



There is no need to disable interrupts in bio_copy_block, and the local
only mappings helps to avoid any sort of problems with stray writes
into the bio data.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20210727055646.118787-8-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 732022b8

drivers/md/dm-writecache.c

+2 −3
Original line number Diff line number Diff line
@@ -1214,14 +1214,13 @@ static void memcpy_flushcache_optimized(void *dest, void *source, size_t size) 
static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)

{

	void *buf;

	unsigned long flags;

	unsigned size;

	int rw = bio_data_dir(bio);

	unsigned remaining_size = wc->block_size;



	do {

		struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);

		buf = bvec_kmap_irq(&bv, &flags);

		buf = bvec_kmap_local(&bv);

		size = bv.bv_len;

		if (unlikely(size > remaining_size))

			size = remaining_size;
@@ -1239,7 +1238,7 @@ static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data 
			memcpy_flushcache_optimized(data, buf, size);

		}



		bvec_kunmap_irq(buf, &flags);

		kunmap_local(buf);



		data = (char *)data + size;

		remaining_size -= size;