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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-20 00:31:08 +0300 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2020-03-21 02:07:32 +0300 |
| commit | 71559219ce36d5861ecc1d31697687c08819b6e5 (patch) | |
| tree | 4f4e6387109186239f53b7639dcb83f4bcff8f80 | |
| parent | ac309e7744bee222df6de0122facaf2d9706fa70 (diff) | |
| download | linux-71559219ce36d5861ecc1d31697687c08819b6e5.tar.xz | |
HID: intel-ish-hid: ishtp-dev.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>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| -rw-r--r-- | drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h b/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h index 39e0e6c73adf..1cc6364aa957 100644 --- a/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h +++ b/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h @@ -214,7 +214,7 @@ struct ishtp_device { const struct ishtp_hw_ops *ops; size_t mtu; uint32_t ishtp_msg_hdr; - char hw[0] __aligned(sizeof(void *)); + char hw[] __aligned(sizeof(void *)); }; static inline unsigned long ishtp_secs_to_jiffies(unsigned long sec) |