libreCMC-next/target/linux/generic/backport-4.14/040-v4.17-0002-mtd-get-rid-of-the-mtd_add_device_partitions.patch

From 0dbe4ea78d69756efeb0bba0764f6bd4a9ee9567 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Tue, 16 Jan 2018 16:45:42 +0100
Subject: [PATCH] mtd: get rid of the mtd_add_device_partitions()
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This simplifies code a bit by:
1) Avoiding an extra (tiny) function
2) Checking for amount of parsed (found) partitions just once
3) Avoiding clearing/filling struct mtd_partitions manually

With this commit proper functions are called directly from the
mtd_device_parse_register(). It doesn't need to use minor tricks like
memsetting struct to 0 to trigger an expected
mtd_add_device_partitions() behavior.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
---
 drivers/mtd/mtdcore.c | 43 ++++++++++++-------------------------------
 1 file changed, 12 insertions(+), 31 deletions(-)

--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -636,21 +636,6 @@ out_error:
 	return ret;
 }
 
-static int mtd_add_device_partitions(struct mtd_info *mtd,
-				     struct mtd_partitions *parts)
-{
-	const struct mtd_partition *real_parts = parts->parts;
-	int nbparts = parts->nr_parts;
-
-	if (!nbparts && !device_is_registered(&mtd->dev))
-		return add_mtd_device(mtd);
-
-	if (nbparts > 0)
-		return add_mtd_partitions(mtd, real_parts, nbparts);
-
-	return 0;
-}
-
 /*
  * Set a few defaults based on the parent devices, if not provided by the
  * driver
@@ -701,7 +686,7 @@ int mtd_device_parse_register(struct mtd
 			      const struct mtd_partition *parts,
 			      int nr_parts)
 {
-	struct mtd_partitions parsed;
+	struct mtd_partitions parsed = { };
 	int ret;
 
 	mtd_set_dev_defaults(mtd);
@@ -712,24 +697,20 @@ int mtd_device_parse_register(struct mtd
 			return ret;
 	}
 
-	memset(&parsed, 0, sizeof(parsed));
-
+	/* Prefer parsed partitions over driver-provided fallback */
 	ret = parse_mtd_partitions(mtd, types, &parsed, parser_data);
-	if ((ret < 0 || parsed.nr_parts == 0) && parts && nr_parts) {
-		/* Fall back to driver-provided partitions */
-		parsed = (struct mtd_partitions){
-			.parts		= parts,
-			.nr_parts	= nr_parts,
-		};
-	} else if (ret < 0) {
-		/* Didn't come up with parsed OR fallback partitions */
-		pr_info("mtd: failed to find partitions; one or more parsers reports errors (%d)\n",
-			ret);
-		/* Don't abort on errors; we can still use unpartitioned MTD */
-		memset(&parsed, 0, sizeof(parsed));
+	if (!ret && parsed.nr_parts) {
+		parts = parsed.parts;
+		nr_parts = parsed.nr_parts;
 	}
 
-	ret = mtd_add_device_partitions(mtd, &parsed);
+	if (nr_parts)
+		ret = add_mtd_partitions(mtd, parts, nr_parts);
+	else if (!device_is_registered(&mtd->dev))
+		ret = add_mtd_device(mtd);
+	else
+		ret = 0;
+
 	if (ret)
 		goto out;