diff options
| author |   Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 07:20:17 -0600 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-23 19:24:51 +0100 |
| commit | 6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch) | |
| tree | 3ce2cf2b7886400097251d33c05435653bcafe9b /drivers/usb/host/ehci.h | |
| parent | usb: musb: core: remove useless cast for driver.name (diff) | |
| download | linux-dev-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.xz linux-dev-6bc3f3979edce0b11deb685a4c817abb7d74b227.zip | |
USB: 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")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200220132017.GA29262@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci.h')
| -rw-r--r-- | drivers/usb/host/ehci.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index ac5e967907d1..229b3de319e6 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -255,7 +255,7 @@ struct ehci_hcd { /* one per controller */ struct list_head tt_list; /* platform-specific data -- must come last */ - unsigned long priv[0] __aligned(sizeof(s64)); + unsigned long priv[] __aligned(sizeof(s64)); }; /* convert between an HCD pointer and the corresponding EHCI_HCD */ @@ -460,7 +460,7 @@ struct ehci_iso_sched { struct list_head td_list; unsigned span; unsigned first_packet; - struct ehci_iso_packet packet[0]; + struct ehci_iso_packet packet[]; }; /* |