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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-12 18:14:01 -0600 |
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committer | Joerg Roedel <jroedel@suse.de> | 2020-02-28 16:19:40 +0100 |
commit | e26060e1d47a535e0bc41a00708b79bc52dc9fb3 (patch) | |
tree | 1df333e9b2ba1b858c522344bdfef5c412fecac9 /drivers/iommu | |
parent | f8788d86ab28f61f7b46eb6be375f8a726783636 (diff) | |
download | linux-e26060e1d47a535e0bc41a00708b79bc52dc9fb3.tar.gz linux-e26060e1d47a535e0bc41a00708b79bc52dc9fb3.tar.bz2 linux-e26060e1d47a535e0bc41a00708b79bc52dc9fb3.zip |
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>
Diffstat (limited to 'drivers/iommu')
-rw-r--r-- | drivers/iommu/qcom_iommu.c | 2 |
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 { |