linux/drivers/thermal/qcom
Gustavo A. R. Silva 0a8cdc8b14 thermal: qcom: tsens.h: 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 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200319184838.GA25767@embeddedor.com
2020-03-23 15:20:47 +01:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
qcom-spmi-temp-alarm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284 2019-06-05 17:36:37 +02:00
tsens-8960.c drivers: thermal: tsens: Pass around struct tsens_sensor as a constant 2020-03-20 12:17:48 +01:00
tsens-common.c drivers: thermal: tsens: Add watchdog support 2020-03-20 12:17:48 +01:00
tsens-v0_1.c drivers: thermal: tsens: De-constify struct tsens_features 2020-03-20 12:17:48 +01:00
tsens-v1.c drivers: thermal: tsens: De-constify struct tsens_features 2020-03-20 12:17:48 +01:00
tsens-v2.c drivers: thermal: tsens: Add watchdog support 2020-03-20 12:17:48 +01:00
tsens.c drivers: thermal: tsens: Remove unnecessary irq flag 2020-03-20 12:17:48 +01:00
tsens.h thermal: qcom: tsens.h: Replace zero-length array with flexible-array member 2020-03-23 15:20:47 +01:00