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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-27 07:13:07 -0600
committerBoris Brezillon <boris.brezillon@collabora.com>2020-02-28 09:36:01 +0100
commitcd851485ef297fc439fd398c4b26e1b2e497045a (patch)
treeac42b83fa5c4377c3b6936f667f9b3dcf795e9fb
parent65ec1d0ddf24e9ebba1e5d87e78c20ccf53199cd (diff)
downloadlinux-cd851485ef297fc439fd398c4b26e1b2e497045a.tar.bz2
i3c: master: 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> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Link: https://lore.kernel.org/linux-i3c/20200227131307.GA24935@embeddedor
-rw-r--r--drivers/i3c/master/dw-i3c-master.c2
-rw-r--r--drivers/i3c/master/i3c-master-cdns.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index bd26c3b9634e..5c5306cd50ec 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -221,7 +221,7 @@ struct dw_i3c_xfer {
struct completion comp;
int ret;
unsigned int ncmds;
- struct dw_i3c_cmd cmds[0];
+ struct dw_i3c_cmd cmds[];
};
struct dw_i3c_master {
diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index 54712793709e..3fee8bd7fe20 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -388,7 +388,7 @@ struct cdns_i3c_xfer {
struct completion comp;
int ret;
unsigned int ncmds;
- struct cdns_i3c_cmd cmds[0];
+ struct cdns_i3c_cmd cmds[];
};
struct cdns_i3c_data {