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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-27 13:07:21 -0600
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-03-04 11:08:17 +0100
commit27565c9e22ddd158f918456b2712a06b05b4da5e (patch)
tree89d936ddd649b79d6ba9e90535b487b13c2c32d7 /drivers/powercap
parent98d54f81e36ba3bf92172791eba5ca5bd813989b (diff)
downloadlinux-27565c9e22ddd158f918456b2712a06b05b4da5e.tar.bz2
powercap: idle_inject: 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] Lastly, fix the following checkpatch warning: WARNING: Prefer 'unsigned long' over 'unsigned long int' as the int is unnecessary + unsigned long int cpumask[]; 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> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/powercap')
-rw-r--r--drivers/powercap/idle_inject.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index cd1270614cc6..e9bbd3c42eef 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c
@@ -67,7 +67,7 @@ struct idle_inject_device {
struct hrtimer timer;
unsigned int idle_duration_us;
unsigned int run_duration_us;
- unsigned long int cpumask[0];
+ unsigned long cpumask[];
};
static DEFINE_PER_CPU(struct idle_inject_thread, idle_inject_thread);