| Message ID | 20230328143442.2684167-3-yebin@huaweicloud.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | limit set the host state by sysfs | expand |
On 3/28/23 9:34 AM, Ye Bin wrote: > From: Ye Bin <yebin10@huawei.com> > > Introduce 'blocked' sysfs api to control scsi host blocking IO. > Use this founction for test. Perhaps we can use this to do some fault > recovery or firmware upgrades, as long as the driver support is good, If it's for testing only then do people like a debugfs type of interface is better? If it's for actual production use like firmware upgrades and they can't handle IO while they are doing the upgrade, then I think you need to do more than just set a bit to prevent new IO. You also need to handle cmds that have passed the scsi_queue_rq ready checks and have not been processed by the driver's queuecommand. Also there are some issues like cmds can still timeout and so you will get scsi_host_template->eh* calls still. > > diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h > index 587cc767bb67..3e916dbac1cb 100644 > --- a/include/scsi/scsi_host.h > +++ b/include/scsi/scsi_host.h > @@ -659,6 +659,9 @@ struct Scsi_Host { > /* The transport requires the LUN bits NOT to be stored in CDB[1] */ > unsigned no_scsi2_lun_in_cdb:1; > > + /* True host will blocking IO */ > + unsigned host_blockio:1; > + Maybe rename to host_user_blocked to match the host_self_blocked naming. I would make the comment similar to host_self_blocked's comment but instead of the host requesting it userspace did. > /* > * Optional work queue to be utilized by the transport > */
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 903aa9de46e5..cad1981ab528 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -345,6 +345,37 @@ store_shost_eh_deadline(struct device *dev, struct device_attribute *attr, static DEVICE_ATTR(eh_deadline, S_IRUGO | S_IWUSR, show_shost_eh_deadline, store_shost_eh_deadline); +static ssize_t +store_shost_blocked(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + int err; + bool blocked; + struct Scsi_Host *shost = class_to_shost(dev); + + err = kstrtobool(buf, &blocked); + if (err) + return err; + + if (shost->host_blockio != blocked) { + shost->host_blockio = blocked; + if (!blocked) + scsi_run_host_queues(shost); + } + + return count; +} + +static ssize_t +show_shost_blocked(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct Scsi_Host *shost = class_to_shost(dev); + + return snprintf(buf, 20, "%d\n", shost->host_blockio); +} +static DEVICE_ATTR(blocked, S_IRUGO | S_IWUSR, + show_shost_blocked, store_shost_blocked); + shost_rd_attr(unique_id, "%u\n"); shost_rd_attr(cmd_per_lun, "%hd\n"); shost_rd_attr(can_queue, "%d\n"); @@ -397,6 +428,7 @@ static struct attribute *scsi_sysfs_shost_attrs[] = { &dev_attr_host_reset.attr, &dev_attr_eh_deadline.attr, &dev_attr_nr_hw_queues.attr, + &dev_attr_blocked.attr, NULL }; diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 587cc767bb67..3e916dbac1cb 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -659,6 +659,9 @@ struct Scsi_Host { /* The transport requires the LUN bits NOT to be stored in CDB[1] */ unsigned no_scsi2_lun_in_cdb:1; + /* True host will blocking IO */ + unsigned host_blockio:1; + /* * Optional work queue to be utilized by the transport */