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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-23 19:12:17 -0500
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 15:44:56 -0500
commita1c4b9247ddfb62fe3a23eb53d250382e82fae77 (patch)
treece39639376e8348493b225fa8723218b705f91cd
parent70f1451ec98ee43d2c66d2caa5ae6935ee97f90a (diff)
downloadlinux-a1c4b9247ddfb62fe3a23eb53d250382e82fae77.tar.bz2
rio.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/rio.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/rio.h b/include/linux/rio.h
index 317bace5ac64..2cd637268b4f 100644
--- a/include/linux/rio.h
+++ b/include/linux/rio.h
@@ -100,7 +100,7 @@ struct rio_switch {
u32 port_ok;
struct rio_switch_ops *ops;
spinlock_t lock;
- struct rio_dev *nextdev[0];
+ struct rio_dev *nextdev[];
};
/**
@@ -201,7 +201,7 @@ struct rio_dev {
u8 hopcount;
struct rio_dev *prev;
atomic_t state;
- struct rio_switch rswitch[0]; /* RIO switch info */
+ struct rio_switch rswitch[]; /* RIO switch info */
};
#define rio_dev_g(n) list_entry(n, struct rio_dev, global_list)