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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 16:20:17 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-23 21:24:51 +0300 |
| commit | 6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch) | |
| tree | 3ce2cf2b7886400097251d33c05435653bcafe9b /include/linux/usb.h | |
| parent | 2f41c8a25feb822203f92e17f3720397805d0cfd (diff) | |
| download | linux-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.xz | |
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 'include/linux/usb.h')
| -rw-r--r-- | include/linux/usb.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/usb.h b/include/linux/usb.h index ca1a5f1e1c5e..9f3c721c70dc 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -325,7 +325,7 @@ struct usb_interface_cache { /* variable-length array of alternate settings for this interface, * stored in no particular order */ - struct usb_host_interface altsetting[0]; + struct usb_host_interface altsetting[]; }; #define ref_to_usb_interface_cache(r) \ container_of(r, struct usb_interface_cache, ref) @@ -1589,7 +1589,7 @@ struct urb { int error_count; /* (return) number of ISO errors */ void *context; /* (in) context for completion */ usb_complete_t complete; /* (in) completion routine */ - struct usb_iso_packet_descriptor iso_frame_desc[0]; + struct usb_iso_packet_descriptor iso_frame_desc[]; /* (in) ISO ONLY */ }; |