I'll resubmit with a better description. As for the return value, if you look at the mailing list history you'll see that I already tried that approach (and was actually advised to do it this way):
http://marc.info/?l=linux-scsi&m=136881989601276&w=2 On Fri, Sep 06, 2013 at 07:03:26PM +0200, Bartlomiej Zolnierkiewicz wrote: > > 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.bra...@intel.com> > > Signed-off-by: Arjan van de Ven <ar...@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, > > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
