linux/drivers/scsi/mvsas
Gustavo A. R. Silva 5febf6d6ae scsi: 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")

Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-03-11 23:07:56 -04:00
..
Kconfig treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 457 2019-06-19 17:09:09 +02:00
Makefile treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_64xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_64xx.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_94xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_94xx.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_chips.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_defs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
mv_init.c compat_ioctl: scsi: handle HDIO commands from drivers 2020-01-03 09:42:52 +01:00
mv_sas.c scsi: mvsas: remove redundant assignment to variable rc 2019-09-30 22:42:41 -04:00
mv_sas.h scsi: Replace zero-length array with flexible-array member 2020-03-11 23:07:56 -04:00