[PATCH/RESEND 2/2] Hard disk S3 resume time optimization

[Todd E Brandt <todd.e.brandt@linux.intel.com>]

Part 2 of the hard disk resume optimization patch, this one applies
to the scsi subsystem.


Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

 drivers/scsi/sd.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 81 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 86fcf2c..d4bf784 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -107,6 +107,7 @@ static int  sd_remove(struct device *);
 static void sd_shutdown(struct device *);
 static int sd_suspend(struct device *);
 static int sd_resume(struct device *);
+static int sd_resume_async(struct device *);
 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);
@@ -484,7 +485,7 @@ static struct class sd_disk_class = {
 
 static const struct dev_pm_ops sd_pm_ops = {
 	.suspend		= sd_suspend,
-	.resume			= sd_resume,
+	.resume			= sd_resume_async,
 	.poweroff		= sd_suspend,
 	.restore		= sd_resume,
 	.runtime_suspend	= sd_suspend,
@@ -3137,6 +3138,85 @@ done:
 	return ret;
 }
 
+static void sd_resume_async_end(struct request *rq, int error)
+{
+	struct scsi_sense_hdr sshdr;
+	struct scsi_disk *sdkp = rq->end_io_data;
+	char *sense = rq->sense;
+
+	if (error) {
+		sd_printk(KERN_WARNING, sdkp, "START FAILED\n");
+		sd_print_result(sdkp, error);
+		if (sense && (driver_byte(error) & DRIVER_SENSE)) {
+			scsi_normalize_sense(sense,
+				SCSI_SENSE_BUFFERSIZE, &sshdr);
+			sd_print_sense_hdr(sdkp, &sshdr);
+		}
+	} else
+		sd_printk(KERN_NOTICE, sdkp, "START SUCCESS\n");
+
+	kfree(sense);
+	rq->sense = NULL;
+	rq->end_io_data = NULL;
+	__blk_put_request(rq->q, rq);
+	scsi_disk_put(sdkp);
+}
+
+static int sd_resume_async(struct device *dev)
+{
+	unsigned char cmd[6] = { START_STOP };
+	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
+	struct request *req;
+	char *sense = NULL;
+	int ret = 0;
+
+	if (!sdkp->device->manage_start_stop)
+		goto error;
+
+	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
+
+	cmd[4] |= 1;
+
+	if (sdkp->device->start_stop_pwr_cond)
+		cmd[4] |= 1 << 4;	/* Active or Standby */
+
+	if (!scsi_device_online(sdkp->device)) {
+		ret = -ENODEV;
+		goto error;
+	}
+
+	req = blk_get_request(sdkp->device->request_queue, 0, __GFP_WAIT);
+	if (!req) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
+	if (!sense) {
+		ret = -ENOMEM;
+		goto error_sense;
+	}
+
+	req->cmd_len = COMMAND_SIZE(cmd[0]);
+	memcpy(req->cmd, cmd, req->cmd_len);
+	req->sense = sense;
+	req->sense_len = 0;
+	req->retries = SD_MAX_RETRIES;
+	req->timeout = SD_TIMEOUT;
+	req->cmd_type = REQ_TYPE_BLOCK_PC;
+	req->cmd_flags |= REQ_PM | REQ_QUIET | REQ_PREEMPT;
+
+	req->end_io_data = sdkp;
+	blk_execute_rq_nowait(req->q, NULL, req, 1, sd_resume_async_end);
+	return 0;
+
+ error_sense:
+	__blk_put_request(req->q, req);
+ error:
+	scsi_disk_put(sdkp);
+	return ret;
+}
+
 /**
  *	init_sd - entry point for this driver (both when built in or when
  *	a module).