[PATCH 5/6] sd: don't start disks on system resume

From: Phillip Susi <psusi@ubuntu.com>
To: todd.e.brandt@linux.intel.com
Cc: tj@kernel.org, JBottomley@parallels.com,
	linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: [PATCH 5/6] sd: don't start disks on system resume
Date: Mon, 16 Dec 2013 18:30:56 -0500	[thread overview]
Message-ID: <1387236657-4852-6-git-send-email-psusi@ubuntu.com> (raw)
In-Reply-To: <1387236657-4852-1-git-send-email-psusi@ubuntu.com>

Instead of forcing a disk to start up with the START STOP UNIT
command when the system resumes, let it stay asleep if runtime
pm is enabled, and it will start the drive when it is accessed.
Query the drive to see if it starts up on its own ( like most
ATA disks do ) and update the runtime pm status if so.
---
 drivers/scsi/sd.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++------
 drivers/scsi/sd.h |  1 +
 2 files changed, 86 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index e6c4bff..98c082a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -107,7 +107,8 @@ static int  sd_remove(struct device *);
 static void sd_shutdown(struct device *);
 static int sd_suspend_system(struct device *);
 static int sd_suspend_runtime(struct device *);
-static int sd_resume(struct device *);
+static int sd_resume_system(struct device *);
+static int sd_resume_runtime(struct device *dev);
 static void sd_rescan(struct device *);
 static int sd_done(struct scsi_cmnd *);
 static int sd_eh_action(struct scsi_cmnd *, unsigned char *, int, int);
@@ -486,11 +487,11 @@ static struct class sd_disk_class = {
 
 static const struct dev_pm_ops sd_pm_ops = {
 	.suspend		= sd_suspend_system,
-	.resume			= sd_resume,
+	.resume			= sd_resume_system,
 	.poweroff		= sd_suspend_system,
-	.restore		= sd_resume,
+	.restore		= sd_resume_system,
 	.runtime_suspend	= sd_suspend_runtime,
-	.runtime_resume		= sd_resume,
+	.runtime_resume		= sd_resume_runtime,
 };
 
 static struct scsi_driver sd_template = {
@@ -3166,22 +3167,97 @@ static int sd_suspend_runtime(struct device *dev)
 	return sd_suspend_common(dev, false);
 }
 
-static int sd_resume(struct device *dev)
+static int sd_resume_runtime(struct device *dev)
 {
 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
 	int ret = 0;
 
-	if (!sdkp->device->manage_start_stop)
-		goto done;
-
 	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
+	dump_stack();
 	ret = sd_start_stop_device(sdkp, 1);
 
-done:
 	scsi_disk_put(sdkp);
 	return ret;
 }
 
+#ifdef CONFIG_PM_RUNTIME
+static void sd_resume_work(struct work_struct *work)
+{
+	struct scsi_disk *sdkp = container_of(work, struct scsi_disk, resume_work.work);
+	struct scsi_device *sdp = sdkp->device;
+	struct device *dev = &sdkp->dev;
+	int res;
+	unsigned char cmd[10] = { 0 };
+	struct scsi_sense_hdr sshdr;
+	const int timeout = sdp->request_queue->rq_timeout;
+
+	cmd[0] = REQUEST_SENSE;
+	printk(KERN_NOTICE "Requesting sense\n");
+	res = scsi_execute_req_flags(sdp, cmd, DMA_NONE, NULL, 0,
+				     &sshdr, timeout, SD_MAX_RETRIES,
+				     NULL, REQ_PM);
+	if (res) {
+		sd_print_result(sdkp, res);
+		goto wakeup;
+	}
+	if (driver_byte(res) & DRIVER_SENSE)
+		sd_print_sense_hdr(sdkp, &sshdr);
+	/* we need to evaluate the error return  */
+	if (scsi_sense_valid(&sshdr) &&
+	    sshdr.sense_key == 0 &&
+	    sshdr.asc == 0 &&
+	    sshdr.ascq == 0)
+		goto wakeup;
+
+	/* finalize suspend */
+	printk(KERN_NOTICE "Finalizing suspend\n");
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_enable(dev);
+	blk_post_runtime_suspend(sdp->request_queue, 0);
+	scsi_disk_put(sdkp);
+	return;
+
+wakeup:
+	/* abort suspend */
+	sd_printk(KERN_NOTICE, sdkp, "Activating disk %s\n", kobject_name(&dev->kobj));
+	blk_post_runtime_suspend(sdp->request_queue, -EBUSY);
+	scsi_disk_put(sdkp);
+}
+#endif
+
+
+static int sd_resume_system(struct device *dev)
+{
+	struct scsi_disk *sdkp;
+#ifdef CONFIG_PM_RUNTIME
+	struct scsi_device *sdp;
+	int ret = 0;
+
+	sdkp = scsi_disk_get_from_dev(dev);
+	sdp = sdkp->device;
+	if (!scsi_device_online(sdp))
+	{
+		ret = -ENODEV;
+		goto err;
+	}
+	sd_printk(KERN_NOTICE, sdkp, "Suspending disk\n");
+	/* force runtime pm status to suspending */
+	blk_pre_runtime_suspend(sdp->request_queue);
+	execute_in_process_context(sd_resume_work,
+				   &sdkp->resume_work);
+
+err:
+	scsi_disk_put(sdkp);
+	return ret;
+#else
+	if (sdkp->device->manage_start_stop)
+		return sd_resume_runtime(dev);
+	return 0;
+#endif
+}
+
+
 /**
  *	init_sd - entry point for this driver (both when built in or when
  *	a module).
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 26895ff..0b8afb3 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -90,6 +90,7 @@ struct scsi_disk {
 	unsigned	lbpvpd : 1;
 	unsigned	ws10 : 1;
 	unsigned	ws16 : 1;
+	struct execute_work resume_work;
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)
 
-- 
1.8.3.2

