Add a mpath_dev file so that the multipath disk can be looked up from per-path gendisk directory.
The following is an example of this usage: $ ls -l /dev/sdc brw-rw---- 1 root disk 8, 32 Feb 24 16:08 /dev/sdc $ cat /sys/class/scsi_mpath_disk/0/sdc/multipath/sdc:0/mpath_dev 8:32 This can be used by a util like lsscsi, which would find that the gendisk for the per-path scsi_device is missing. Signed-off-by: John Garry <[email protected]> --- drivers/scsi/sd.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 48 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 409c0937764d9..f5922a9fe6c1b 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -4198,6 +4198,51 @@ static int sd_mpath_revalidate_head(struct scsi_disk *sdkp) return ret; } + +static ssize_t sd_mpath_dev_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct gendisk *gd = dev_to_disk(dev); + struct scsi_disk *sdkp = gd->private_data; + struct sd_mpath_disk *sd_mpath_disk = sdkp->sd_mpath_disk; + struct mpath_disk *mpath_disk = sd_mpath_disk->mpath_disk; + struct gendisk *disk = mpath_disk->disk; + struct device *disk_dev = disk_to_dev(disk); + + return print_dev_t(page, disk_dev->devt); +} +static DEVICE_ATTR(mpath_dev, 0444, sd_mpath_dev_show, NULL); + +static struct attribute *sd_mpath_dev_attrs[] = { + &dev_attr_mpath_dev.attr, + NULL +}; + +static umode_t sd_mpath_dev_attr_is_visible(struct kobject *kobj, + struct attribute *attr, int i) +{ + struct device *dev = kobj_to_dev(kobj); + struct gendisk *gd = dev_to_disk(dev); + struct scsi_disk *sdkp = gd->private_data; + struct scsi_device *sdev = sdkp->device; + struct scsi_mpath_device *scsi_mpath_device = sdev->scsi_mpath_dev; + + if (!scsi_mpath_device) + return 0; + + return attr->mode; +} + +static const struct attribute_group sd_mpath_dev_attr_group = { + .is_visible = sd_mpath_dev_attr_is_visible, + .attrs = sd_mpath_dev_attrs, +}; + +static const struct attribute_group *sd_mpath_dev_groups[] = { + &sd_mpath_dev_attr_group, + NULL +}; + static int sd_mpath_get_disk(struct sd_mpath_disk *sd_mpath_disk) { if (!get_device(&sd_mpath_disk->dev)) @@ -4461,6 +4506,8 @@ static int sd_mpath_revalidate_head(struct scsi_disk *sdkp) static void sd_mpath_add_disk(struct scsi_disk *sdkp) { } + +#define sd_mpath_dev_groups NULL #endif /** * sd_probe - called during driver initialization and whenever a @@ -4602,7 +4649,7 @@ static int sd_probe(struct device *dev) sdp->host->rpm_autosuspend_delay); } - error = device_add_disk(dev, gd, NULL); + error = device_add_disk(dev, gd, sd_mpath_dev_groups); if (error) { sd_mpath_fail_probe(sdkp); device_unregister(&sdkp->disk_dev); -- 2.43.5
