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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-24 01:23:01 +0300
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 23:44:54 +0300
commitbeb69f15a095245c5cc62389eea93002b41d2eb9 (patch)
treee8e976e48400222b78b5304a80e7de8a43c6efe9 /include/linux/energy_model.h
parent192199464d6cccb084356add54b3a48d6dde9f96 (diff)
downloadlinux-beb69f15a095245c5cc62389eea93002b41d2eb9.tar.xz
energy_model.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 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Diffstat (limited to 'include/linux/energy_model.h')
-rw-r--r--include/linux/energy_model.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index d249b88a4d5a..ade6486a3382 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -36,7 +36,7 @@ struct em_cap_state {
struct em_perf_domain {
struct em_cap_state *table;
int nr_cap_states;
- unsigned long cpus[0];
+ unsigned long cpus[];
};
#ifdef CONFIG_ENERGY_MODEL