[RFC PATCH 3/4] disk: part: fall-through if "ubi" requested but ubifs not mounted

[Sam Edwards <cfsworks@gmail.com>]

Since we're adding the ability to access static UBI volumes as block
devices, it is no longer an error to use the "ubi" ifname with UBIFS
unmounted.

Ideally, the access to UBIFS should instead be called "ubifs" but it
would break backwards compatibility to change this. Instead, use the
UBIFS mount status to disambiguate what the user means by "ubi"

There is no change in functionality in this patch: UBIFS access works
the same and an error still occurs when using "ubi" without UBIFS
mounted. The only difference is that now, the error message is a plain
"Bad device specification" and does not suggest using ubifsmount.

Signed-off-by: Sam Edwards <CFSworks@gmail.com>
---
 disk/part.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/disk/part.c b/disk/part.c
index 0a03b8213d..1ad8277b65 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -492,15 +492,13 @@ int blk_get_device_part_str(const char *ifname, const char *dev_part_str,
 
 #if IS_ENABLED(CONFIG_CMD_UBIFS) && !IS_ENABLED(CONFIG_SPL_BUILD)
 	/*
-	 * Special-case ubi, ubi goes through a mtd, rather than through
-	 * a regular block device.
+	 * Special-case ubifs, which does not go through the block device layer
+	 * and also must be mounted ahead of time. U-Boot has historically
+	 * called this "ubi" too, even though *static* UBI volumes are
+	 * accessible as block devices. For backward compatibility, assume that
+	 * when UBIFS is mounted, the user intends "ubi" to mean "ubifs."
 	 */
-	if (!strcmp(ifname, "ubi")) {
-		if (!ubifs_is_mounted()) {
-			printf("UBIFS not mounted, use ubifsmount to mount volume first!\n");
-			return -EINVAL;
-		}
-
+	if (ubifs_is_mounted() && !strcmp(ifname, "ubi")) {
 		strcpy((char *)info->type, BOOT_PART_TYPE);
 		strcpy((char *)info->name, "UBI");
 		return 0;
-- 
2.41.0