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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-12 18:14:01 -0600
committerJoerg Roedel <jroedel@suse.de>2020-02-28 16:19:40 +0100
commite26060e1d47a535e0bc41a00708b79bc52dc9fb3 (patch)
tree1df333e9b2ba1b858c522344bdfef5c412fecac9
parentf8788d86ab28f61f7b46eb6be375f8a726783636 (diff)
iommu/qcom: 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> Signed-off-by: Joerg Roedel <jroedel@suse.de>
-rw-r--r--drivers/iommu/qcom_iommu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
index 4328da0b0a9f..f6117726da99 100644
--- a/drivers/iommu/qcom_iommu.c
+++ b/drivers/iommu/qcom_iommu.c
@@ -48,7 +48,7 @@ struct qcom_iommu_dev {
void __iomem *local_base;
u32 sec_id;
u8 num_ctxs;
- struct qcom_iommu_ctx *ctxs[0]; /* indexed by asid-1 */
+ struct qcom_iommu_ctx *ctxs[]; /* indexed by asid-1 */
};
struct qcom_iommu_ctx {