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authorGustavo A. R. Silva <gustavoars@kernel.org>2020-05-07 22:25:17 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2020-05-22 19:45:15 +0300
commitf740e64c6cd6d9c26b4b9fc0a8d339b215147af7 (patch)
treecd997eaea3f09dcec6a71a17381ca022d946e7c7
parent1202a442a31fd2e53cde1a9677d9f7005e48fd6e (diff)
downloadlinux-f740e64c6cd6d9c26b4b9fc0a8d339b215147af7.tar.xz
thermal: imx8mm: Replace zero-length array with flexible-array
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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. 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 <gustavoars@kernel.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20200507192517.GA16557@embeddedor
-rw-r--r--drivers/thermal/imx8mm_thermal.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/thermal/imx8mm_thermal.c b/drivers/thermal/imx8mm_thermal.c
index 0d60f8d7894f..e6061e26d4ac 100644
--- a/drivers/thermal/imx8mm_thermal.c
+++ b/drivers/thermal/imx8mm_thermal.c
@@ -54,7 +54,7 @@ struct imx8mm_tmu {
void __iomem *base;
struct clk *clk;
const struct thermal_soc_data *socdata;
- struct tmu_sensor sensors[0];
+ struct tmu_sensor sensors[];
};
static int imx8mm_tmu_get_temp(void *data, int *temp)