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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-23 18:32:01 -0500
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 15:44:55 -0500
commit859b494111b196853fd8c1852c6b57ef33738b50 (patch)
treefd52a03dd5254369293ecf86d29c18c8c0708d75
parent312322722872324939f0d0347a6e41807c2d4c56 (diff)
list_lru.h: 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>
-rw-r--r--include/linux/list_lru.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index d5ceb2839a2d..9dcaa3e582c9 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -34,7 +34,7 @@ struct list_lru_one {
struct list_lru_memcg {
struct rcu_head rcu;
/* array of per cgroup lists, indexed by memcg_cache_id */
- struct list_lru_one *lru[0];
+ struct list_lru_one *lru[];
};
struct list_lru_node {