dm crypt: use dm_submit_bio_remap

Care was taken to support kcryptd_io_read being called from crypt_map
or workqueue.  Use of an intermediate CRYPT_MAP_READ_GFP gfp_t
(defined as GFP_NOWAIT) should protect from maintenance burden if that
flag were to change for some reason.
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-crypt.c

@@ -1828,6 +1828,8 @@ static void crypt_endio(struct bio *clone)
 	crypt_dec_pending(io);
 }
 
+#define CRYPT_MAP_READ_GFP GFP_NOWAIT
+
 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 {
 	struct crypt_config *cc = io->cc;
@@ -1855,7 +1857,7 @@ static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 		return 1;
 	}
 
-	submit_bio_noacct(clone);
+	dm_submit_bio_remap(io->base_bio, clone, (gfp != CRYPT_MAP_READ_GFP));
 	return 0;
 }
 
@@ -1881,7 +1883,7 @@ static void kcryptd_io_write(struct dm_crypt_io *io)
 {
 	struct bio *clone = io->ctx.bio_out;
 
-	submit_bio_noacct(clone);
+	dm_submit_bio_remap(io->base_bio, clone, true);
 }
 
 #define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
@@ -1960,7 +1962,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
 
 	if ((likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) ||
 	    test_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags)) {
-		submit_bio_noacct(clone);
+		dm_submit_bio_remap(io->base_bio, clone, true);
 		return;
 	}
 
@@ -3363,6 +3365,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_bios = 1;
 	ti->limit_swap_bios = true;
+	ti->accounts_remapped_io = true;
 
 	dm_audit_log_ctr(DM_MSG_PREFIX, ti, 1);
 	return 0;
@@ -3431,7 +3434,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
 		io->ctx.r.req = (struct skcipher_request *)(io + 1);
 
 	if (bio_data_dir(io->base_bio) == READ) {
-		if (kcryptd_io_read(io, GFP_NOWAIT))
+		if (kcryptd_io_read(io, CRYPT_MAP_READ_GFP))
 			kcryptd_queue_read(io);
 	} else
 		kcryptd_queue_crypt(io);
@@ -3626,7 +3629,7 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 static struct target_type crypt_target = {
 	.name   = "crypt",
-	.version = {1, 23, 0},
+	.version = {1, 24, 0},
 	.module = THIS_MODULE,
 	.ctr    = crypt_ctr,
 	.dtr    = crypt_dtr,