linux/drivers/misc/sgi-gru
Gustavo A. R. Silva f490e8aea3 misc: 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>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Link: https://lore.kernel.org/r/20200226222240.GA14474@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-18 12:24:19 +01:00
..
gru_instructions.h Add #includes needed to permit the removal of asm/system.h 2012-03-28 18:30:03 +01:00
gru.h gru: improve GRU TLB dropin statistics 2009-12-16 07:20:17 -08:00
grufault.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
grufile.c misc/sgi-gru: use mmu_notifier_get/put for struct gru_mm_struct 2019-08-16 12:02:59 -03:00
gruhandles.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
gruhandles.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
grukdump.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
grukservices.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
grukservices.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
grulib.h misc: Replace zero-length array with flexible-array member 2020-03-18 12:24:19 +01:00
grumain.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
gruprocfs.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
grutables.h misc: Replace zero-length array with flexible-array member 2020-03-18 12:24:19 +01:00
grutlbpurge.c misc/sgi-gru: use mmu_notifier_get/put for struct gru_mm_struct 2019-08-16 12:02:59 -03:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00