| Message ID | 20200924113842.11670-2-brgl@bgdev.pl |
|---|---|
| State | New |
| Headers | show |
| Series | gpio: mockup: refactoring + documentation | expand |
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 >
On Fri, Sep 25, 2020 at 11:01 AM Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > 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. > But how would it even work - you can allocate strings in so many ways? Also: let's not introduce functions without users. Bart [snip]
On Fri, Sep 25, 2020 at 01:32:01PM +0200, Bartosz Golaszewski wrote: > On Fri, Sep 25, 2020 at 11:01 AM Andy Shevchenko > <andriy.shevchenko@linux.intel.com> wrote: > > > > 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. > > > > But how would it even work - you can allocate strings in so many ways? Yes, that's what I meant in the second part of the first sentence. Something like: static inline char **kalloc_strarray(n, gfp) { return kcalloc(n, sizeof(char *), gfp); } looks good enough, but it's only first part of the equation. > Also: let's not introduce functions without users. Agree.
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);