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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-21 09:06:12 -0600 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2020-02-27 16:02:21 +0100 |
| commit | fa226f1d81e2d3798d30eaa14550d7f35c35e6f3 (patch) | |
| tree | 2063b7d5c04db419fe443d7a2aa39e1cc21cbe4e /drivers/s390/cio | |
| parent | d5d006fa0927c34fa083c8d48e33b1c30b29fd1b (diff) | |
| download | linux-fa226f1d81e2d3798d30eaa14550d7f35c35e6f3.tar.bz2 | |
s390: 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 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Link: https://lkml.kernel.org/r/20200221150612.GA9717@embeddedor
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'drivers/s390/cio')
| -rw-r--r-- | drivers/s390/cio/idset.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/s390/cio/idset.c b/drivers/s390/cio/idset.c index 835de44dbbcc..77d0ea7b381b 100644 --- a/drivers/s390/cio/idset.c +++ b/drivers/s390/cio/idset.c @@ -13,7 +13,7 @@ struct idset { int num_ssid; int num_id; - unsigned long bitmap[0]; + unsigned long bitmap[]; }; static inline unsigned long bitmap_size(int num_ssid, int num_id) |