Hi,
On Thursday, September 05, 2013 05:44:25 PM Todd E Brandt wrote:
> Part 2 of the hard disk resume optimization patch, this one applies
> to the scsi subsystem.
Please update the patch description to say what the patch does (and why).
> Signed-off-by: Todd Brandt <todd.e.brandt@xxxxxxxxx>
> Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
>
> 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,
Same comment as with patch #1.
When the command execution later fails the error will be now lost
(->resume returned 0 already and nothing can be done to fix it).
Sorry but this looks like a wrong approach and you should fix
the PM layer to do async ->resume when possible instead.
> .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).
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
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