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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-14 18:13:02 +0100 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2020-02-19 13:18:40 +0100 |
| commit | 35e032462bf8c7847d4ef7b70a3c8dc17f814c97 (patch) | |
| tree | e3c5ae89e48ea97496eb8768aa0d5536ae44c6f0 | |
| parent | dmaengine: tegra210-adma: Replace zero-length array with flexible-array member (diff) | |
| download | linux-35e032462bf8c7847d4ef7b70a3c8dc17f814c97.tar.xz linux-35e032462bf8c7847d4ef7b70a3c8dc17f814c97.zip | |
dmanegine: ioat/dca: 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>
Link: https://lore.kernel.org/r/20200214171302.GA20586@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>
| -rw-r--r-- | drivers/dma/ioat/dca.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dma/ioat/dca.c b/drivers/dma/ioat/dca.c index be61c32a876f..0be385587c4c 100644 --- a/drivers/dma/ioat/dca.c +++ b/drivers/dma/ioat/dca.c @@ -102,7 +102,7 @@ struct ioat_dca_priv { int max_requesters; int requester_count; u8 tag_map[IOAT_TAG_MAP_LEN]; - struct ioat_dca_slot req_slots[0]; + struct ioat_dca_slot req_slots[]; }; static int ioat_dca_dev_managed(struct dca_provider *dca, |