openwrt/target/linux/generic/backport-4.14/042-v4.18-0001-mtd-move-code-adding-registering-partitions-to-the-p.patch

From 5ac67ce36cfe38b4c104a42ce52c5c8d526f1c95 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Tue, 27 Mar 2018 22:35:41 +0200
Subject: [PATCH] mtd: move code adding (registering) partitions to the
 parse_mtd_partitions()
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This commit slightly simplifies the code. Every parse_mtd_partitions()
caller (out of two existing ones) had to add partitions & cleanup parser
on its own. This moves that responsibility into the function.

That change also allows dropping struct mtd_partitions argument.

There is one minor behavior change caused by this cleanup. If
parse_mtd_partitions() fails to add partitions (add_mtd_partitions()
return an error) then mtd_device_parse_register() will still try to
add (register) fallback partitions. It's a real corner case affecting
one of uncommon error paths and shouldn't cause any harm.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
---
 drivers/mtd/mtdcore.c | 14 ++++----------
 drivers/mtd/mtdcore.h |  1 -
 drivers/mtd/mtdpart.c | 44 ++++++++++++++++----------------------------
 3 files changed, 20 insertions(+), 39 deletions(-)

--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -686,7 +686,6 @@ int mtd_device_parse_register(struct mtd
 			      const struct mtd_partition *parts,
 			      int nr_parts)
 {
-	struct mtd_partitions parsed = { };
 	int ret;
 
 	mtd_set_dev_defaults(mtd);
@@ -698,13 +697,10 @@ int mtd_device_parse_register(struct mtd
 	}
 
 	/* Prefer parsed partitions over driver-provided fallback */
-	ret = parse_mtd_partitions(mtd, types, &parsed, parser_data);
-	if (!ret && parsed.nr_parts) {
-		parts = parsed.parts;
-		nr_parts = parsed.nr_parts;
-	}
-
-	if (nr_parts)
+	ret = parse_mtd_partitions(mtd, types, parser_data);
+	if (ret > 0)
+		ret = 0;
+	else if (nr_parts)
 		ret = add_mtd_partitions(mtd, parts, nr_parts);
 	else if (!device_is_registered(&mtd->dev))
 		ret = add_mtd_device(mtd);
@@ -730,8 +726,6 @@ int mtd_device_parse_register(struct mtd
 	}
 
 out:
-	/* Cleanup any parsed partitions */
-	mtd_part_parser_cleanup(&parsed);
 	if (ret && device_is_registered(&mtd->dev))
 		del_mtd_device(mtd);
 
--- a/drivers/mtd/mtdcore.h
+++ b/drivers/mtd/mtdcore.h
@@ -15,7 +15,6 @@ int del_mtd_partitions(struct mtd_info *
 struct mtd_partitions;
 
 int parse_mtd_partitions(struct mtd_info *master, const char * const *types,
-			 struct mtd_partitions *pparts,
 			 struct mtd_part_parser_data *data);
 
 void mtd_part_parser_cleanup(struct mtd_partitions *parts);
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -383,20 +383,7 @@ static inline void free_partition(struct
  */
 static int mtd_parse_part(struct mtd_part *slave, const char *const *types)
 {
-	struct mtd_partitions parsed;
-	int err;
-
-	err = parse_mtd_partitions(&slave->mtd, types, &parsed, NULL);
-	if (err)
-		return err;
-	else if (!parsed.nr_parts)
-		return -ENOENT;
-
-	err = add_mtd_partitions(&slave->mtd, parsed.parts, parsed.nr_parts);
-
-	mtd_part_parser_cleanup(&parsed);
-
-	return err;
+	return parse_mtd_partitions(&slave->mtd, types, NULL);
 }
 
 static struct mtd_part *allocate_partition(struct mtd_info *parent,
@@ -1006,30 +993,27 @@ static int mtd_part_of_parse(struct mtd_
 }
 
 /**
- * parse_mtd_partitions - parse MTD partitions
+ * parse_mtd_partitions - parse and register MTD partitions
+ *
  * @master: the master partition (describes whole MTD device)
  * @types: names of partition parsers to try or %NULL
- * @pparts: info about partitions found is returned here
  * @data: MTD partition parser-specific data
  *
- * This function tries to find partition on MTD device @master. It uses MTD
- * partition parsers, specified in @types. However, if @types is %NULL, then
- * the default list of parsers is used. The default list contains only the
+ * This function tries to find & register partitions on MTD device @master. It
+ * uses MTD partition parsers, specified in @types. However, if @types is %NULL,
+ * then the default list of parsers is used. The default list contains only the
  * "cmdlinepart" and "ofpart" parsers ATM.
  * Note: If there are more then one parser in @types, the kernel only takes the
  * partitions parsed out by the first parser.
  *
  * This function may return:
  * o a negative error code in case of failure
- * o zero otherwise, and @pparts will describe the partitions, number of
- *   partitions, and the parser which parsed them. Caller must release
- *   resources with mtd_part_parser_cleanup() when finished with the returned
- *   data.
+ * o number of found partitions otherwise
  */
 int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
-			 struct mtd_partitions *pparts,
 			 struct mtd_part_parser_data *data)
 {
+	struct mtd_partitions pparts = { };
 	struct mtd_part_parser *parser;
 	int ret, err = 0;
 
@@ -1043,7 +1027,7 @@ int parse_mtd_partitions(struct mtd_info
 		 * handled in a separated function.
 		 */
 		if (!strcmp(*types, "ofpart")) {
-			ret = mtd_part_of_parse(master, pparts);
+			ret = mtd_part_of_parse(master, &pparts);
 		} else {
 			pr_debug("%s: parsing partitions %s\n", master->name,
 				 *types);
@@ -1054,13 +1038,17 @@ int parse_mtd_partitions(struct mtd_info
 				parser ? parser->name : NULL);
 			if (!parser)
 				continue;
-			ret = mtd_part_do_parse(parser, master, pparts, data);
+			ret = mtd_part_do_parse(parser, master, &pparts, data);
 			if (ret <= 0)
 				mtd_part_parser_put(parser);
 		}
 		/* Found partitions! */
-		if (ret > 0)
-			return 0;
+		if (ret > 0) {
+			err = add_mtd_partitions(master, pparts.parts,
+						 pparts.nr_parts);
+			mtd_part_parser_cleanup(&pparts);
+			return err ? err : pparts.nr_parts;
+		}
 		/*
 		 * Stash the first error we see; only report it if no parser
 		 * succeeds