scsi: sd: Do not issue commands to suspended disks on shutdown

If an error occurs when resuming a host adapter before the devices
attached to the adapter are resumed, the adapter low level driver may
remove the scsi host, resulting in a call to sd_remove() for the
disks of the host. This in turn results in a call to sd_shutdown() which
will issue a synchronize cache command and a start stop unit command to
spindown the disk. sd_shutdown() issues the commands only if the device
is not already runtime suspended but does not check the power state for
system-wide suspend/resume. That is, the commands may be issued with the
device in a suspended state, which causes PM resume to hang, forcing a
reset of the machine to recover.

Fix this by tracking the suspended state of a disk by introducing the
suspended boolean field in the scsi_disk structure. This flag is set to
true when the disk is suspended is sd_suspend_common() and resumed with
sd_resume(). When suspended is true, sd_shutdown() is not executed from
sd_remove().

Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sd.c

@@ -3741,6 +3741,7 @@ static int sd_remove(struct device *dev)
 
 	device_del(&sdkp->disk_dev);
 	del_gendisk(sdkp->disk);
+	if (!sdkp->suspended)
 		sd_shutdown(dev);
 
 	put_disk(sdkp->disk);
@@ -3872,6 +3873,9 @@ static int sd_suspend_common(struct device *dev, bool runtime)
 			ret = 0;
 	}
 
+	if (!ret)
+		sdkp->suspended = true;
+
 	return ret;
 }
 
@@ -3891,21 +3895,26 @@ static int sd_suspend_runtime(struct device *dev)
 static int sd_resume(struct device *dev, bool runtime)
 {
 	struct scsi_disk *sdkp = dev_get_drvdata(dev);
-	int ret;
+	int ret = 0;
 
 	if (!sdkp)	/* E.g.: runtime resume at the start of sd_probe() */
 		return 0;
 
-	if (!sd_do_start_stop(sdkp->device, runtime))
+	if (!sd_do_start_stop(sdkp->device, runtime)) {
+		sdkp->suspended = false;
 		return 0;
+	}
 
 	if (!sdkp->device->no_start_on_resume) {
 		sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
 		ret = sd_start_stop_device(sdkp, 1);
 	}
 
-	if (!ret)
+	if (!ret) {
 		opal_unlock_from_suspend(sdkp->opal_dev);
+		sdkp->suspended = false;
+	}
+
 	return ret;
 }
 

drivers/scsi/sd.h

@@ -131,6 +131,7 @@ struct scsi_disk {
 	u8		provisioning_mode;
 	u8		zeroing_mode;
 	u8		nr_actuators;		/* Number of actuators */
+	bool		suspended;	/* Disk is suspended (stopped) */
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	cache_override : 1; /* temp override of WCE,RCD */
 	unsigned	WCE : 1;	/* state of disk WCE bit */