On Fri, Apr 21, 2017 at 02:13:02PM -0700, Song Liu wrote: > When a device is deleted through sysfs handle "delete", the code > locks shost->scan_mutex. If multiple devices are deleted at the > same time, these deletes will be handled in series. > > On the other hand, some devices do long latency IO during deletion, > for example, sd_shutdown() may do sync cache and/or start_stop. > It is not necessary for these commands to run in series. > > To reduce latency of parallel "delete" requests, this patch reduces > the protection of scan_mutex. The only function with Scsi_Host > called in __scsi_remove_device() is the optional slave_destroy(). > Therefore, the protection of scan_mutex is only necessary for this > function. And I don't think it makes sense for slave_destroy either. Please do a quick audit of the instances and drop the lock for it, too. > > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index 82dfe07..e7a9e28 100644 > --- a/drivers/scsi/scsi_sysfs.c > +++ b/drivers/scsi/scsi_sysfs.c > @@ -610,7 +610,7 @@ static int scsi_sdev_check_buf_bit(const char *buf) > return 1; > else if (buf[0] == '0') > return 0; > - else > + else > return -EINVAL; Also the patch has a few odd whitespace changes like this. Please remove those before reposting.
