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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-12 19:04:25 -0600
committerJason Gunthorpe <jgg@mellanox.com>2020-02-20 13:33:51 -0400
commit5b361328ca649534d721e4eae20c96ccbe702ce7 (patch)
treeaecd94c8ba19a810b66a90a2914b5834ba2832a4 /drivers/infiniband/hw/mthca
parent52c5e9e7497b728b53a84cbd5873c4b707d10d55 (diff)
RDMA: 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") Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> # added a few more
Diffstat (limited to 'drivers/infiniband/hw/mthca')
-rw-r--r--drivers/infiniband/hw/mthca/mthca_memfree.c2
-rw-r--r--drivers/infiniband/hw/mthca/mthca_memfree.h2
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
index 78a48aea3faf..fa808582b08b 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.c
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -58,7 +58,7 @@ struct mthca_user_db_table {
u64 uvirt;
struct scatterlist mem;
int refcount;
- } page[0];
+ } page[];
};
static void mthca_free_icm_pages(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.h b/drivers/infiniband/hw/mthca/mthca_memfree.h
index da9b8f9b884f..f9a2e65e2ff5 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.h
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.h
@@ -68,7 +68,7 @@ struct mthca_icm_table {
int lowmem;
int coherent;
struct mutex mutex;
- struct mthca_icm *icm[0];
+ struct mthca_icm *icm[];
};
struct mthca_icm_iter {