[SCSI] sd: Allow protection_type to be overridden

We have encountered a few devices that misbehaved when operating in T10
PI mode. Allow T10 PI protection type to be overridden from userland.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 9f7fc39891b8..e04c302fa4f7 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -262,6 +262,28 @@ sd_show_protection_type(struct device *dev, struct device_attribute *attr,
 }
 
 static ssize_t
+sd_store_protection_type(struct device *dev, struct device_attribute *attr,
+                         const char *buf, size_t count)
+{
+        struct scsi_disk *sdkp = to_scsi_disk(dev);
+        unsigned int val;
+        int err;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+
+        err = kstrtouint(buf, 10, &val);
+
+        if (err)
+                return err;
+
+        if (val >= 0 && val <= SD_DIF_TYPE3_PROTECTION)
+                sdkp->protection_type = val;
+
+        return count;
+}
+
+static ssize_t
 sd_show_protection_mode(struct device *dev, struct device_attribute *attr,
                         char *buf)
 {
@@ -381,7 +403,8 @@ static struct device_attribute sd_disk_attrs[] = {
                sd_store_allow_restart),
         __ATTR(manage_start_stop, S_IRUGO|S_IWUSR, sd_show_manage_start_stop,
                sd_store_manage_start_stop),
-        __ATTR(protection_type, S_IRUGO, sd_show_protection_type, NULL),
+        __ATTR(protection_type, S_IRUGO|S_IWUSR, sd_show_protection_type,
+               sd_store_protection_type),
         __ATTR(protection_mode, S_IRUGO, sd_show_protection_mode, NULL),
         __ATTR(app_tag_own, S_IRUGO, sd_show_app_tag_own, NULL),
         __ATTR(thin_provisioning, S_IRUGO, sd_show_thin_provisioning, NULL),