linux/drivers/dma/ioat
Gustavo A. R. Silva 35e032462b dmanegine: ioat/dca: 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 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200214171302.GA20586@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-02-19 17:48:40 +05:30
..
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
dca.c dmanegine: ioat/dca: Replace zero-length array with flexible-array member 2020-02-19 17:48:40 +05:30
dma.c ioat: ioat_alloc_ring() failure handling. 2019-12-27 12:06:06 +05:30
dma.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 7 2019-05-21 11:28:40 +02:00
hw.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 7 2019-05-21 11:28:40 +02:00
init.c dmaengine: ioat: Support in-use unbind 2019-12-24 10:18:37 +05:30
prep.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 291 2019-06-05 17:36:38 +02:00
registers.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 7 2019-05-21 11:28:40 +02:00
sysfs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 291 2019-06-05 17:36:38 +02:00