mtd: cmdlinepart: revise error handling

This patch revises and fixes error handling in the command line mtd
partitions parser. Namely:
1. we ignored return code of 'mtdpart_setup_real()'.
2. instead of returning 0 for failure and 1 for success, teach
   'mtdpart_setup_real()' to return real error codes.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/cmdlinepart.c

@@ -39,11 +39,10 @@
 
 #include <linux/kernel.h>
 #include <linux/slab.h>
-
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
-#include <linux/bootmem.h>
 #include <linux/module.h>
+#include <linux/err.h>
 
 /* error message prefix */
 #define ERRP "mtd: "
@@ -110,7 +109,7 @@ static struct mtd_partition * newpart(char *s,
 		if (size < PAGE_SIZE)
 		{
 			printk(KERN_ERR ERRP "partition size too small (%lx)\n", size);
-			return NULL;
+			return ERR_PTR(-EINVAL);
 		}
 	}
 
@@ -138,7 +137,7 @@ static struct mtd_partition * newpart(char *s,
 		if (!p)
 		{
 			printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
-			return NULL;
+			return ERR_PTR(-EINVAL);
 		}
 		name_len = p - name;
 		s = p + 1;
@@ -172,13 +171,13 @@ static struct mtd_partition * newpart(char *s,
 		if (size == SIZE_REMAINING)
 		{
 			printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
-			return NULL;
+			return ERR_PTR(-EINVAL);
 		}
 		/* more partitions follow, parse them */
 		parts = newpart(s + 1, &s, num_parts, this_part + 1,
 				&extra_mem, extra_mem_size);
-		if (!parts)
-			return NULL;
+		if (IS_ERR(parts))
+			return parts;
 	}
 	else
 	{	/* this is the last partition: allocate space for all */
@@ -189,7 +188,7 @@ static struct mtd_partition * newpart(char *s,
 			     extra_mem_size;
 		parts = kzalloc(alloc_size, GFP_KERNEL);
 		if (!parts)
-			return NULL;
+			return ERR_PTR(-ENOMEM);
 		extra_mem = (unsigned char *)(parts + *num_parts);
 	}
 	/* enter this partition (offset will be calculated later if it is zero at this point) */
@@ -245,7 +244,7 @@ static int mtdpart_setup_real(char *s)
 		if (!(p = strchr(s, ':')))
 		{
 			printk(KERN_ERR ERRP "no mtd-id\n");
-			return 0;
+			return -EINVAL;
 		}
 		mtd_id_len = p - mtd_id;
 
@@ -262,7 +261,7 @@ static int mtdpart_setup_real(char *s)
 				(unsigned char**)&this_mtd, /* out: extra mem */
 				mtd_id_len + 1 + sizeof(*this_mtd) +
 				sizeof(void*)-1 /*alignment*/);
-		if(!parts)
+		if (IS_ERR(parts))
 		{
 			/*
 			 * An error occurred. We're either:
@@ -271,7 +270,7 @@ static int mtdpart_setup_real(char *s)
 			 * Either way, this mtd is hosed and we're
 			 * unlikely to succeed in parsing any more
 			 */
-			 return 0;
+			 return PTR_ERR(parts);
 		 }
 
 		/* align this_mtd */
@@ -299,11 +298,11 @@ static int mtdpart_setup_real(char *s)
 		if (*s != ';')
 		{
 			printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
-			return 0;
+			return -EINVAL;
 		}
 		s++;
 	}
-	return 1;
+	return 0;
 }
 
 /*
@@ -318,13 +317,16 @@ static int parse_cmdline_partitions(struct mtd_info *master,
 				    struct mtd_part_parser_data *data)
 {
 	unsigned long offset;
-	int i;
+	int i, err;
 	struct cmdline_mtd_partition *part;
 	const char *mtd_id = master->name;
 
 	/* parse command line */
-	if (!cmdline_parsed)
-		mtdpart_setup_real(cmdline);
+	if (!cmdline_parsed) {
+		err = mtdpart_setup_real(cmdline);
+		if (err)
+			return err;
+	}
 
 	for(part = partitions; part; part = part->next)
 	{