linux-kernel - [PATCH v3 01/10] lib: string_helpers: provide kfree

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Message-Id: <20200929101004.20288-2-brgl@bgdev.pl>
Date:   Tue, 29 Sep 2020 12:09:55 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Jonathan Corbet <corbet@....net>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Kent Gibson <warthog618@...il.com>
Cc:     linux-gpio@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH v3 01/10] lib: string_helpers: provide kfree_strarray()

From: Bartosz Golaszewski <bgolaszewski@...libre.com>

There's a common pattern of dynamically allocating an array of char
pointers and then also dynamically allocating each string in this
array. Provide a helper for freeing such a string array with one call.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 include/linux/string_helpers.h |  2 ++
 lib/string_helpers.c           | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 86f150c2a6b6..fa06dcdc481e 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -94,4 +94,6 @@ char *kstrdup_quotable(const char *src, gfp_t gfp);
 char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp);
 char *kstrdup_quotable_file(struct file *file, gfp_t gfp);
 
+void kfree_strarray(char **array, size_t n);
+
 #endif
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 963050c0283e..efeee2353613 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -649,3 +649,27 @@ char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
 	return pathname;
 }
 EXPORT_SYMBOL_GPL(kstrdup_quotable_file);
+
+/**
+ * kfree_strarray - free a number of dynamically allocated strings contained
+ *                  in an array and the array itself
+ *
+ * @array: Dynamically allocated array of strings to free. If NULL - the
+ *         function does nothing.
+ * @n: Number of strings (starting from the beginning of the array) to free.
+ *
+ * Passing a non-null @array and @n == 0 as well as NULL @array  are valid
+ * use-cases.
+ */
+void kfree_strarray(char **array, size_t n)
+{
+	unsigned int i;
+
+	if (!array)
+		return;
+
+	for (i = 0; i < n; i++)
+		kfree(array[i]);
+	kfree(array);
+}
+EXPORT_SYMBOL_GPL(kfree_strarray);
-- 
2.26.1