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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-20 07:20:17 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-02-23 19:24:51 +0100
commit6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch)
tree3ce2cf2b7886400097251d33c05435653bcafe9b /include/linux/usb.h
parent2f41c8a25feb822203f92e17f3720397805d0cfd (diff)
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.h4
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 */
};