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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-13 16:57:00 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2020-02-13 17:09:47 -0800
commita1b9b65edfd8f195dafaebf68f7d321eb9b3ab82 (patch)
tree34fe042c28be17515b9c279be642462cdc29067b
parentcfb8d7811f815d17babadd87436300261fd54de7 (diff)
downloadlwn-a1b9b65edfd8f195dafaebf68f7d321eb9b3ab82.tar.gz
lwn-a1b9b65edfd8f195dafaebf68f7d321eb9b3ab82.zip
Input: gpio_keys - replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: https://lore.kernel.org/r/20200213002600.GA31916@embeddedor.com Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
-rw-r--r--drivers/input/keyboard/gpio_keys.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index 1f56d53454b2..53c9ff338dea 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -55,7 +55,7 @@ struct gpio_keys_drvdata {
struct input_dev *input;
struct mutex disable_lock;
unsigned short *keymap;
- struct gpio_button_data data[0];
+ struct gpio_button_data data[];
};
/*