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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200507151758.GA4962@embeddedor
Introduce infrastructure for supporting Factory Test Mode (FTM) of the
wireless LAN subsystem. In order for the user space to access the
firmware in test mode the relevant netlink channel needs to be exposed
from the kernel driver.
The above is achieved as follows:
1) Register wcn36xx driver to testmode callback from netlink
2) Add testmode callback implementation to handle incoming FTM commands
3) Add FTM command packet structure
4) Add handling for GET_BUILD_RELEASE_NUMBER (msgid=0x32A2)
5) Add generic handling for all PTT_MSG packets
Signed-off-by: Eyal Ilsar <eilsar@codeaurora.org>
Signed-off-by: Ramon Fried <ramon.fried@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
