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| author |   Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-27 07:13:07 -0600 |
|---|---|---|
| committer |   Boris Brezillon <boris.brezillon@collabora.com> | 2020-02-28 09:36:01 +0100 |
| commit | cd851485ef297fc439fd398c4b26e1b2e497045a (patch) | |
| tree | ac42b83fa5c4377c3b6936f667f9b3dcf795e9fb /drivers/i3c | |
| parent | i3c: Simplify i3c_device_match_id() (diff) | |
| download | linux-dev-cd851485ef297fc439fd398c4b26e1b2e497045a.tar.xz linux-dev-cd851485ef297fc439fd398c4b26e1b2e497045a.zip | |
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
Diffstat (limited to 'drivers/i3c')
| -rw-r--r-- | drivers/i3c/master/dw-i3c-master.c | 2 | ||||
| -rw-r--r-- | drivers/i3c/master/i3c-master-cdns.c | 2 |
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 { |