kernel: fix parsing fixed subpartitions

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 76 insertions, 0 deletions

diff --git a/target/linux/generic/pending-5.4/410-mtd-parsers-ofpart-fix-parsing-subpartitions.patch b/target/linux/generic/pending-5.4/410-mtd-parsers-ofpart-fix-parsing-subpartitions.patch
new file mode 100644
index 0000000000..d0fc1d50e2
--- /dev/null
+++ b/target/linux/generic/pending-5.4/410-mtd-parsers-ofpart-fix-parsing-subpartitions.patch
@@ -0,0 +1,76 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Thu, 6 May 2021 12:33:58 +0200
+Subject: [PATCH] mtd: parsers: ofpart: fix parsing subpartitions
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+ofpart was recently patched to not scan random partition nodes as
+subpartitions. That change unfortunately broke scanning valid
+subpartitions like:
+
+partitions {
+	compatible = "fixed-partitions";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	partition@0 {
+		compatible = "fixed-partitions";
+		label = "bootloader";
+		reg = <0x0 0x100000>;
+
+		partition@0 {
+			label = "config";
+			reg = <0x80000 0x80000>;
+		};
+	};
+};
+
+Fix that regression by adding 1 more code path. We actually need 3
+conditional blocks to support 3 possible cases. This change also makes
+code easier to understand & follow.
+
+Reported-by: David Bauer <mail@david-bauer.net>
+Fixes: 2d751203aacf ("mtd: parsers: ofpart: limit parsing of deprecated DT syntax
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+ drivers/mtd/parsers/ofpart_core.c | 26 ++++++++++++++------------
+ 1 file changed, 14 insertions(+), 12 deletions(-)
+
+--- a/drivers/mtd/parsers/ofpart_core.c
++++ b/drivers/mtd/parsers/ofpart_core.c
+@@ -57,20 +57,22 @@ static int parse_fixed_partitions(struct
+ 	if (!mtd_node)
+ 		return 0;
+ 
+-	ofpart_node = of_get_child_by_name(mtd_node, "partitions");
+-	if (!ofpart_node && !mtd_is_partition(master)) {
+-		/*
+-		 * We might get here even when ofpart isn't used at all (e.g.,
+-		 * when using another parser), so don't be louder than
+-		 * KERN_DEBUG
+-		 */
+-		pr_debug("%s: 'partitions' subnode not found on %pOF. Trying to parse direct subnodes as partitions.\n",
+-			 master->name, mtd_node);
++	if (!mtd_is_partition(master)) { /* Master */
++		ofpart_node = of_get_child_by_name(mtd_node, "partitions");
++		if (!ofpart_node) {
++			/*
++			 * We might get here even when ofpart isn't used at all (e.g.,
++			 * when using another parser), so don't be louder than
++			 * KERN_DEBUG
++			 */
++			pr_debug("%s: 'partitions' subnode not found on %pOF. Trying to parse direct subnodes as partitions.\n",
++				master->name, mtd_node);
++			ofpart_node = mtd_node;
++			dedicated = false;
++		}
++	} else { /* Partition */
+ 		ofpart_node = mtd_node;
+-		dedicated = false;
+ 	}
+-	if (!ofpart_node)
+-		return 0;
+ 
+ 	of_id = of_match_node(parse_ofpart_match_table, ofpart_node);
+ 	if (dedicated && !of_id) {