sd: Detect non-rotational devices

Detect non-rotational devices and set the queue flag accordingly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

---

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -50,6 +50,7 @@
 #include <linux/string_helpers.h>
 #include <linux/async.h>
 #include <asm/uaccess.h>
+#include <asm/unaligned.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -1781,6 +1801,29 @@ void sd_read_app_tag_own(struct scsi_dis
 }
 
 /**
+ * sd_read_block_characteristics - Query block dev. characteristics
+ * @disk: disk to query
+ */
+static void sd_read_block_characteristics(struct scsi_disk *sdkp)
+{
+	char *buffer;
+	u16 rot;
+
+	/* Block Device Characteristics VPD */
+	buffer = scsi_get_vpd_page(sdkp->device, 0xb1);
+
+	if (buffer == NULL)
+		return;
+
+	rot = get_unaligned_be16(&buffer[4]);
+
+	if (rot == 1)
+		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, sdkp->disk->queue);
+
+	kfree(buffer);
+}
+
+/**
  *	sd_revalidate_disk - called the first time a new disk is seen,
  *	performs disk spin up, read_capacity, etc.
  *	@disk: struct gendisk we care about
@@ -1817,6 +1883,7 @@ static int sd_revalidate_disk(struct gen
 	 */
 	if (sdkp->media_present) {
 		sd_read_capacity(sdkp, buffer);
+		sd_read_block_characteristics(sdkp);
 		sd_read_write_protect_flag(sdkp, buffer);
 		sd_read_cache_type(sdkp, buffer);
 		sd_read_app_tag_own(sdkp, buffer);
@@ -1957,6 +2025,8 @@ static void sd_probe_async(void *data, a
 	add_disk(gd);
 	sd_dif_config_host(sdkp);
 
+	sd_revalidate_disk(gd);
+
 	sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
 		  sdp->removable ? "removable " : "");