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linux-next/include/linux/greybus
Gustavo A. R. Silva 84c1e51d7d greybus: Replace zero-length array with flexible-array
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>
Link: https://lore.kernel.org/r/20200507185318.GA14393@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-13 13:59:13 +02:00
..
bundle.h
connection.h
control.h
greybus_id.h
greybus_manifest.h
greybus_protocols.h greybus: Replace zero-length array with flexible-array 2020-05-13 13:59:13 +02:00
hd.h
interface.h
manifest.h
module.h
operation.h staging: greybus: fix more header declarations 2019-08-28 17:24:22 +02:00
svc.h staging: greybus: fix more header declarations 2019-08-28 17:24:22 +02:00