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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-14 11:13:02 -0600
committerVinod Koul <vkoul@kernel.org>2020-02-19 17:48:40 +0530
commit35e032462bf8c7847d4ef7b70a3c8dc17f814c97 (patch)
treee3c5ae89e48ea97496eb8768aa0d5536ae44c6f0 /drivers/dma/ioat
parent1ee44529cc79e1ae95dd613e03b0c2434da8d052 (diff)
downloadlinux-35e032462bf8c7847d4ef7b70a3c8dc17f814c97.tar.bz2
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>
Diffstat (limited to 'drivers/dma/ioat')
-rw-r--r--drivers/dma/ioat/dca.c2
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,