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Diffstat (limited to 'drivers/md/dm-io.c')
-rw-r--r--drivers/md/dm-io.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ed9c86cd053..4789c42d9a3 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -353,7 +353,7 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
{
struct io io;
- if (num_regions > 1 && rw != WRITE) {
+ if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
WARN_ON(1);
return -EIO;
}
@@ -390,7 +390,7 @@ static int async_io(struct dm_io_client *client, unsigned int num_regions,
{
struct io *io;
- if (num_regions > 1 && rw != WRITE) {
+ if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
WARN_ON(1);
fn(1, context);
return -EIO;
@@ -436,7 +436,12 @@ static int dp_init(struct dm_io_request *io_req, struct dpages *dp)
}
/*
- * New collapsed (a)synchronous interface
+ * New collapsed (a)synchronous interface.
+ *
+ * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
+ * the queue with blk_unplug() some time later or set the BIO_RW_SYNC bit in
+ * io_req->bi_rw. If you fail to do one of these, the IO will be submitted to
+ * the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
*/
int dm_io(struct dm_io_request *io_req, unsigned num_regions,
struct dm_io_region *where, unsigned long *sync_error_bits)