linux-kernel - [PATCH v1 2/5] driver core: Use kasprintf() instead of fixed buffer formatting

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Message-ID: <20240821154839.604259-3-andriy.shevchenko@linux.intel.com>
Date: Wed, 21 Aug 2024 18:48:20 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
	Zijun Hu <quic_zijuhu@...cinc.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1 2/5] driver core: Use kasprintf() instead of fixed buffer formatting

Improve readability and maintainability by replacing a hardcoded string
allocation and formatting by the use of the kasprintf() helper.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/base/core.c | 70 +++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 38 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 6b9d3d255135..f5b5b6bcdf35 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -10,6 +10,7 @@
 
 #include <linux/acpi.h>
 #include <linux/blkdev.h>
+#include <linux/cleanup.h>
 #include <linux/cpufreq.h>
 #include <linux/device.h>
 #include <linux/dma-map-ops.h> /* for dma_default_coherent */
@@ -563,24 +564,11 @@ static struct class devlink_class = {
 
 static int devlink_add_symlinks(struct device *dev)
 {
+	char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
 	int ret;
-	size_t len;
 	struct device_link *link = to_devlink(dev);
 	struct device *sup = link->supplier;
 	struct device *con = link->consumer;
-	char *buf;
-
-	len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
-		  strlen(dev_bus_name(con)) + strlen(dev_name(con)));
-	len += strlen(":");
-	/*
-	 * we kzalloc() memory for symlink name of both supplier and
-	 * consumer, so explicitly take into account both prefix.
-	 */
-	len += max(strlen("supplier:"), strlen("consumer:")) + 1;
-	buf = kzalloc(len, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
 
 	ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
 	if (ret)
@@ -590,58 +578,64 @@ static int devlink_add_symlinks(struct device *dev)
 	if (ret)
 		goto err_con;
 
-	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
-	ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
+	buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
+	if (!buf_con) {
+		ret = -ENOMEM;
+		goto err_con_dev;
+	}
+
+	ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf_con);
 	if (ret)
 		goto err_con_dev;
 
-	snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
-	ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
+	buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
+	if (!buf_sup) {
+		ret = -ENOMEM;
+		goto err_sup_dev;
+	}
+
+	ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf_sup);
 	if (ret)
 		goto err_sup_dev;
 
 	goto out;
 
 err_sup_dev:
-	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
-	sysfs_remove_link(&sup->kobj, buf);
+	sysfs_remove_link(&sup->kobj, buf_con);
 err_con_dev:
 	sysfs_remove_link(&link->link_dev.kobj, "consumer");
 err_con:
 	sysfs_remove_link(&link->link_dev.kobj, "supplier");
 out:
-	kfree(buf);
 	return ret;
 }
 
 static void devlink_remove_symlinks(struct device *dev)
 {
+	char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
 	struct device_link *link = to_devlink(dev);
-	size_t len;
 	struct device *sup = link->supplier;
 	struct device *con = link->consumer;
-	char *buf;
 
 	sysfs_remove_link(&link->link_dev.kobj, "consumer");
 	sysfs_remove_link(&link->link_dev.kobj, "supplier");
 
-	len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
-		  strlen(dev_bus_name(con)) + strlen(dev_name(con)));
-	len += strlen(":");
-	len += max(strlen("supplier:"), strlen("consumer:")) + 1;
-	buf = kzalloc(len, GFP_KERNEL);
-	if (!buf) {
-		WARN(1, "Unable to properly free device link symlinks!\n");
-		return;
+	if (device_is_registered(con)) {
+		buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
+		if (!buf_sup)
+			goto out;
+		sysfs_remove_link(&con->kobj, buf_sup);
 	}
 
-	if (device_is_registered(con)) {
-		snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
-		sysfs_remove_link(&con->kobj, buf);
-	}
-	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
-	sysfs_remove_link(&sup->kobj, buf);
-	kfree(buf);
+	buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
+	if (!buf_con)
+		goto out;
+	sysfs_remove_link(&sup->kobj, buf_con);
+
+	return;
+
+out:
+	WARN(1, "Unable to properly free device link symlinks!\n");
 }
 
 static struct class_interface devlink_class_intf = {
-- 
2.43.0.rc1.1336.g36b5255a03ac