linux-stable/drivers/scsi/aic94xx
Gustavo A. R. Silva 00b42b70ae scsi: libsas: 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")

Link: https://lore.kernel.org/r/20200507192147.GA16206@embeddedor
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-05-11 22:26:32 -04:00
..
aic94xx.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_dev.c SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
aic94xx_dump.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_dump.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_hwi.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_hwi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_init.c compat_ioctl: scsi: handle HDIO commands from drivers 2020-01-03 09:42:52 +01:00
aic94xx_reg.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_reg.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_reg_def.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_sas.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_scb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_sds.c scsi: libsas: Replace zero-length array with flexible-array 2020-05-11 22:26:32 -04:00
aic94xx_sds.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_seq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_seq.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_task.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
aic94xx_tmf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 411 2019-06-05 17:37:14 +02:00
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 411 2019-06-05 17:37:14 +02:00