block: add queue flag for SSD/non-rotational devices
We don't want to idle in AS/CFQ if the device doesn't have a seek
penalty. So add a QUEUE_FLAG_NONROT to indicate a non-rotational
device, low level drivers should set this flag upon discovery of
an SSD or similar device type.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 86f77ef..0cf3e61 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -442,6 +442,7 @@
#define QUEUE_FLAG_SAME_COMP 11 /* force complete on same CPU */
#define QUEUE_FLAG_FAIL_IO 12 /* fake timeout */
#define QUEUE_FLAG_STACKABLE 13 /* supports request stacking */
+#define QUEUE_FLAG_NONROT 14 /* non-rotational device (SSD) */
static inline int queue_is_locked(struct request_queue *q)
{
@@ -547,6 +548,7 @@
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
#define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
+#define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
#define blk_queue_flushing(q) ((q)->ordseq)
#define blk_queue_stackable(q) \
test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)