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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-19 16:38:39 -0500
committerBjorn Andersson <bjorn.andersson@linaro.org>2020-03-25 22:30:46 -0700
commitef17f5193edd42e8913c93d0b601c101c56a15bb (patch)
tree5d0b195d9c0f2fc34a9e0b19f0cee152c059033d /drivers/hwspinlock
parentffd0bbfb378ecd56eac22bf932ccdbf89ac7f725 (diff)
downloadlinux-ef17f5193edd42e8913c93d0b601c101c56a15bb.tar.bz2
hwspinlock: hwspinlock_internal.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") Reviewed-by: Baolin Wang <baolin.wang7@gmail.com> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: https://lore.kernel.org/r/20200319213839.GA10669@embeddedor.com Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Diffstat (limited to 'drivers/hwspinlock')
-rw-r--r--drivers/hwspinlock/hwspinlock_internal.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/hwspinlock/hwspinlock_internal.h b/drivers/hwspinlock/hwspinlock_internal.h
index 9eb6bd020dc7..29892767bb7a 100644
--- a/drivers/hwspinlock/hwspinlock_internal.h
+++ b/drivers/hwspinlock/hwspinlock_internal.h
@@ -56,7 +56,7 @@ struct hwspinlock_device {
const struct hwspinlock_ops *ops;
int base_id;
int num_locks;
- struct hwspinlock lock[0];
+ struct hwspinlock lock[];
};
static inline int hwlock_to_id(struct hwspinlock *hwlock)