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author | Michał Kępień <kernel@kempniu.pl> | 2017-03-08 20:20:10 +0300 |
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committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2017-03-09 01:28:53 +0300 |
commit | fabeb165afd52a3fb05b9b68e5a3550609b8e157 (patch) | |
tree | a5851d7d6d6a45dd1e571b05de4bc07be9670514 /drivers | |
parent | c470abd4fde40ea6a0846a2beab642a578c0b8cd (diff) | |
download | linux-fabeb165afd52a3fb05b9b68e5a3550609b8e157.tar.xz |
Input: sparse-keymap - use a managed allocation for keymap copy
Some platform drivers use devm_input_allocate_device() together with
sparse_keymap_setup() in their .probe callbacks. While using the former
simplifies error handling, using the latter necessitates calling
sparse_keymap_free() in the error path and upon module unloading to
avoid leaking the copy of the keymap allocated by sparse_keymap_setup().
To help prevent such leaks and enable simpler error handling, make
sparse_keymap_setup() use devm_kmemdup() to create the keymap copy so
that it gets automatically freed.
This works for both managed and non-managed input devices as the keymap
is freed after the last reference to the input device is dropped.
Note that actions previously taken by sparse_keymap_free(), i.e. taking
the input device's mutex and zeroing its keycode and keycodemax fields,
are now redundant because the managed keymap will always be freed after
the input device is unregistered.
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/input/sparse-keymap.c | 39 |
1 files changed, 9 insertions, 30 deletions
diff --git a/drivers/input/sparse-keymap.c b/drivers/input/sparse-keymap.c index e7409c45bdd0..12a3ad83296d 100644 --- a/drivers/input/sparse-keymap.c +++ b/drivers/input/sparse-keymap.c @@ -160,12 +160,12 @@ static int sparse_keymap_setkeycode(struct input_dev *dev, * @keymap: Keymap in form of array of &key_entry structures ending * with %KE_END type entry * @setup: Function that can be used to adjust keymap entries - * depending on device's deeds, may be %NULL + * depending on device's needs, may be %NULL * * The function calculates size and allocates copy of the original * keymap after which sets up input device event bits appropriately. - * Before destroying input device allocated keymap should be freed - * with a call to sparse_keymap_free(). + * The allocated copy of the keymap is automatically freed when it + * is no longer needed. */ int sparse_keymap_setup(struct input_dev *dev, const struct key_entry *keymap, @@ -180,19 +180,18 @@ int sparse_keymap_setup(struct input_dev *dev, for (e = keymap; e->type != KE_END; e++) map_size++; - map = kcalloc(map_size, sizeof(struct key_entry), GFP_KERNEL); + map = devm_kmemdup(&dev->dev, keymap, map_size * sizeof(*map), + GFP_KERNEL); if (!map) return -ENOMEM; - memcpy(map, keymap, map_size * sizeof(struct key_entry)); - for (i = 0; i < map_size; i++) { entry = &map[i]; if (setup) { error = setup(dev, entry); if (error) - goto err_out; + return error; } switch (entry->type) { @@ -221,10 +220,6 @@ int sparse_keymap_setup(struct input_dev *dev, dev->setkeycode = sparse_keymap_setkeycode; return 0; - - err_out: - kfree(map); - return error; } EXPORT_SYMBOL(sparse_keymap_setup); @@ -232,29 +227,13 @@ EXPORT_SYMBOL(sparse_keymap_setup); * sparse_keymap_free - free memory allocated for sparse keymap * @dev: Input device using sparse keymap * - * This function is used to free memory allocated by sparse keymap + * This function used to free memory allocated by sparse keymap * in an input device that was set up by sparse_keymap_setup(). - * NOTE: It is safe to cal this function while input device is - * still registered (however the drivers should care not to try to - * use freed keymap and thus have to shut off interrupts/polling - * before freeing the keymap). + * Since sparse_keymap_setup() now uses a managed allocation for the + * keymap copy, use of this function is deprecated. */ void sparse_keymap_free(struct input_dev *dev) { - unsigned long flags; - - /* - * Take event lock to prevent racing with input_get_keycode() - * and input_set_keycode() if we are called while input device - * is still registered. - */ - spin_lock_irqsave(&dev->event_lock, flags); - - kfree(dev->keycode); - dev->keycode = NULL; - dev->keycodemax = 0; - - spin_unlock_irqrestore(&dev->event_lock, flags); } EXPORT_SYMBOL(sparse_keymap_free); |