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")
Unified · Split
| @@ -38,7 +38,7 @@ struct gpio_keys_polled_dev { · 37 unmodified lines | |||
| 38 | const struct gpio_keys_platform_data *pdata; | 38 | const struct gpio_keys_platform_data *pdata; |
| 39 | unsigned long rel_axis_seen[BITS_TO_LONGS(REL_CNT)]; | 39 | unsigned long rel_axis_seen[BITS_TO_LONGS(REL_CNT)]; |
| 40 | unsigned long abs_axis_seen[BITS_TO_LONGS(ABS_CNT)]; | 40 | unsigned long abs_axis_seen[BITS_TO_LONGS(ABS_CNT)]; |
| 41 | struct gpio_keys_button_data data[0]; | 41 | struct gpio_keys_button_data data[]; |
| 42 | }; | 42 | }; |
| 43 | 43 | ||
| 44 | static void gpio_keys_button_event(struct input_dev *input, | 44 | static void gpio_keys_button_event(struct input_dev *input, |