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[1/9] lib: string_helpers: provide kfree_strarray()

Message ID 20200924113842.11670-2-brgl@bgdev.pl
State New
Headers show
Series gpio: mockup: refactoring + documentation | expand

Commit Message

Bartosz Golaszewski Sept. 24, 2020, 11:38 a.m. UTC
From: Bartosz Golaszewski <bgolaszewski@baylibre.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@baylibre.com>
---
 include/linux/string_helpers.h |  2 ++
 lib/string_helpers.c           | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+)

Comments

Andy Shevchenko Sept. 25, 2020, 8:48 a.m. UTC | #1
On Thu, Sep 24, 2020 at 01:38:34PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.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.


For consistency I would like to provide kalloc_strarray(), but it seems a bit
ambiguous. So I'm fine with this going alone.

> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

> ---

>  include/linux/string_helpers.h |  2 ++

>  lib/string_helpers.c           | 22 ++++++++++++++++++++++

>  2 files changed, 24 insertions(+)

> 

> diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h

> index 86f150c2a6b6..55b25120a1c6 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 **str_array, size_t num_str);

> +

>  #endif

> diff --git a/lib/string_helpers.c b/lib/string_helpers.c

> index 963050c0283e..56c01ec8a076 100644

> --- a/lib/string_helpers.c

> +++ b/lib/string_helpers.c

> @@ -649,3 +649,25 @@ 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

> + *


> + * @str_array: Dynamically allocated array of strings to free. If NULL - the

> + *             function does nothing.

> + * @num_str: Number of strings (starting from the beginning of the array) to

> + *           free.


Can we use same names as done for other string array related functions, i.e.
str_array -> array
num_str -> n

?

(See *match_string() APIs)

> + *

> + * Passing a non-null str_array and num_str == 0 as well as NULL str_array and

> + * num_str == 0 are valid use-cases.


You still may refer to the parameters in the description using @param notation,
like @str_array.

> + */

> +void kfree_strarray(char **str_array, size_t num_str)

> +{

> +	unsigned int i;

> +

> +	for (i = 0; i < num_str; i++)

> +		kfree(str_array[i]);

> +	kfree(str_array);

> +}

> +EXPORT_SYMBOL_GPL(kfree_strarray);

> -- 

> 2.26.1

> 


-- 
With Best Regards,
Andy Shevchenko
diff mbox series

Patch

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 86f150c2a6b6..55b25120a1c6 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 **str_array, size_t num_str);
+
 #endif
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 963050c0283e..56c01ec8a076 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -649,3 +649,25 @@  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
+ *
+ * @str_array: Dynamically allocated array of strings to free. If NULL - the
+ *             function does nothing.
+ * @num_str: Number of strings (starting from the beginning of the array) to
+ *           free.
+ *
+ * Passing a non-null str_array and num_str == 0 as well as NULL str_array and
+ * num_str == 0 are valid use-cases.
+ */
+void kfree_strarray(char **str_array, size_t num_str)
+{
+	unsigned int i;
+
+	for (i = 0; i < num_str; i++)
+		kfree(str_array[i]);
+	kfree(str_array);
+}
+EXPORT_SYMBOL_GPL(kfree_strarray);