scsi: target: make the pi_prot_format ConfigFS path readable

ddiss · martinkpetersen · commit b6cd7f34ba13 · 2019-02-04T21:40:32.000-05:00
pi_prot_format conversion to write-only caused userspace breakage. Make the ConfigFS path readable again and hardcode the "0\n" content, matching previous output. Fixes: 6baca76 ("scsi: target: drop unused pi_prot_format attribute storage") Link: https://bugzilla.redhat.com/show_bug.cgi?id=1667505 Reported-by: Lee Duncan <lduncan@suse.com> Reported-by: Laura Abbott <labbott@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: David Disseldorp <ddiss@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
@@ -852,6 +852,12 @@ static ssize_t pi_prot_type_store(struct config_item *item,
 	return count;
 }
 
+/* always zero, but attr needs to remain RW to avoid userspace breakage */
+static ssize_t pi_prot_format_show(struct config_item *item, char *page)
+{
+	return snprintf(page, PAGE_SIZE, "0\n");
+}
+
 static ssize_t pi_prot_format_store(struct config_item *item,
 		const char *page, size_t count)
 {
@@ -1132,7 +1138,7 @@ CONFIGFS_ATTR(, emulate_3pc);
 CONFIGFS_ATTR(, emulate_pr);
 CONFIGFS_ATTR(, pi_prot_type);
 CONFIGFS_ATTR_RO(, hw_pi_prot_type);
-CONFIGFS_ATTR_WO(, pi_prot_format);
+CONFIGFS_ATTR(, pi_prot_format);
 CONFIGFS_ATTR(, pi_prot_verify);
 CONFIGFS_ATTR(, enforce_pr_isids);
 CONFIGFS_ATTR(, is_nonrot);
