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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-13 04:04:25 +0300
committerJason Gunthorpe <jgg@mellanox.com>2020-02-20 20:33:51 +0300
commit5b361328ca649534d721e4eae20c96ccbe702ce7 (patch)
treeaecd94c8ba19a810b66a90a2914b5834ba2832a4 /include/rdma/rdmavt_mr.h
parent52c5e9e7497b728b53a84cbd5873c4b707d10d55 (diff)
downloadlinux-5b361328ca649534d721e4eae20c96ccbe702ce7.tar.xz
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 'include/rdma/rdmavt_mr.h')
-rw-r--r--include/rdma/rdmavt_mr.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/rdma/rdmavt_mr.h b/include/rdma/rdmavt_mr.h
index 72a3856d4057..ce6c888f7fe7 100644
--- a/include/rdma/rdmavt_mr.h
+++ b/include/rdma/rdmavt_mr.h
@@ -85,7 +85,7 @@ struct rvt_mregion {
u8 lkey_published; /* in global table */
struct percpu_ref refcount;
struct completion comp; /* complete when refcount goes to zero */
- struct rvt_segarray *map[0]; /* the segments */
+ struct rvt_segarray *map[]; /* the segments */
};
#define RVT_MAX_LKEY_TABLE_BITS 23