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USB: musb: 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
inadvertenly introduced[3] to the codebase from now on.

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")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200211232519.GA23263@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gustavo A. R. Silva 2020-02-11 17:25:19 -06:00 committed by Greg Kroah-Hartman
parent 6ecc632d4b
commit 21a37aeda6
1 changed files with 1 additions and 1 deletions
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2
drivers/usb/musb/musb_host.c
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@ -2550,7 +2550,7 @@ static int musb_bus_resume(struct usb_hcd *hcd)
struct musb_temp_buffer {
void *kmalloc_ptr;
void *old_xfer_buffer;
u8 data[0];
u8 data[];
};
static void musb_free_temp_buffer(struct urb *urb)