linux-kernel - [PATCH v3 3/4] driver property: constify property arrays values

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Message-Id: <20170201173125.40354-4-dmitry.torokhov@gmail.com>
Date:   Wed,  1 Feb 2017 09:31:24 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc:     linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Wolfram Sang <wsa@...-dreams.de>
Subject: [PATCH v3 3/4] driver property: constify property arrays values

Data that is fed into property arrays should not be modified, so let's mark
relevant pointers as const. This will allow us making source arrays as
const/__initconst.

Also fix memory leaks on errors in property_entry_copy().

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---
 drivers/base/property.c  | 66 +++++++++++++++++++++++++++++++++---------------
 include/linux/property.h | 12 ++++-----
 2 files changed, 52 insertions(+), 26 deletions(-)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index edc09854520b..8cfbc94cafb1 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -682,44 +682,66 @@ int fwnode_property_match_string(struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL_GPL(fwnode_property_match_string);
 
+static int property_copy_string_array(struct property_entry *dst,
+				      const struct property_entry *src)
+{
+	char **d;
+	size_t nval = src->length / sizeof(*d);
+	size_t i;
+
+	d = kcalloc(nval, sizeof(*d), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+
+	for (i = 0; i < nval; i++) {
+		d[i] = kstrdup(src->pointer.str[i], GFP_KERNEL);
+		if (!d[i] && src->pointer.str[i]) {
+			while (--i >= 0)
+				kfree(d[i]);
+			kfree(d);
+			return -ENOMEM;
+		}
+	}
+
+	dst->pointer.str = (void *)d;
+	return 0;
+}
+
 static int property_entry_copy(struct property_entry *dst,
 			       const struct property_entry *src)
 {
-	const char **d, **s;
-	size_t i, nval;
+	int error;
 
 	dst->name = kstrdup(src->name, GFP_KERNEL);
 	if (!dst->name)
 		return -ENOMEM;
 
 	if (src->is_array) {
-		if (!src->length)
-			return -ENODATA;
+		if (!src->length) {
+			error = -ENODATA;
+			goto out_free_name;
+		}
 
 		if (src->is_string) {
-			nval = src->length / sizeof(const char *);
-			dst->pointer.str = kcalloc(nval, sizeof(const char *),
-						   GFP_KERNEL);
-			if (!dst->pointer.str)
-				return -ENOMEM;
-
-			d = dst->pointer.str;
-			s = src->pointer.str;
-			for (i = 0; i < nval; i++) {
-				d[i] = kstrdup(s[i], GFP_KERNEL);
-				if (!d[i] && s[i])
-					return -ENOMEM;
+			error = property_copy_string_array(dst, src);
+			if (error) {
+				error = -ENOMEM;
+				goto out_free_name;
 			}
 		} else {
 			dst->pointer.raw_data = kmemdup(src->pointer.raw_data,
 							src->length, GFP_KERNEL);
-			if (!dst->pointer.raw_data)
-				return -ENOMEM;
+			if (!dst->pointer.raw_data) {
+				error = -ENOMEM;
+				goto out_free_name;
+			}
 		}
 	} else if (src->is_string) {
 		dst->value.str = kstrdup(src->value.str, GFP_KERNEL);
-		if (!dst->value.str && src->value.str)
-			return -ENOMEM;
+		if (!dst->value.str && src->value.str) {
+			error = -ENOMEM;
+			goto out_free_name;
+		}
 	} else {
 		dst->value.raw_data = src->value.raw_data;
 	}
@@ -729,6 +751,10 @@ static int property_entry_copy(struct property_entry *dst,
 	dst->is_string = src->is_string;
 
 	return 0;
+
+out_free_name:
+	kfree(dst->name);
+	return error;
 }
 
 /**
diff --git a/include/linux/property.h b/include/linux/property.h
index 5746e9927016..64e3a9c6d95f 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -160,12 +160,12 @@ struct property_entry {
 	bool is_string;
 	union {
 		union {
-			void *raw_data;
-			u8 *u8_data;
-			u16 *u16_data;
-			u32 *u32_data;
-			u64 *u64_data;
-			const char **str;
+			const void *raw_data;
+			const u8 *u8_data;
+			const u16 *u16_data;
+			const u32 *u32_data;
+			const u64 *u64_data;
+			const char * const *str;
 		} pointer;
 		union {
 			unsigned long long raw_data;
-- 
2.11.0.483.g087da7b7c-goog