On Mon, Oct 19, 2009 at 1:54 AM, Felipe Contreras <felipe.contreras@xxxxxxxxx> wrote: > It seems 'min_t' was used before, and looks cleaner, plus white-space > stuff. > > Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx> > --- > drivers/usb/core/hcd.c | 7 +++---- > 1 files changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c > index 34de475..e6d754e 100644 > --- a/drivers/usb/core/hcd.c > +++ b/drivers/usb/core/hcd.c > @@ -396,8 +396,7 @@ rh_string(int id, struct usb_hcd const *hcd, u8 *data, unsigned len) > case 0: > /* Array of LANGID codes (0x0409 is MSFT-speak for "en-us") */ > /* See http://www.usb.org/developers/docs/USB_LANGIDs.pdf */ > - if (len > 4) > - len = 4; > + len = min_t(unsigned, len, sizeof(langids)); > memcpy(data, langids, len); > return len; > case 1: I still have an unfixed warning: drivers/usb/core/hcd.c: In function ‘rh_string’: /data/public/src/linux/arch/x86/include/asm/string_32.h:74: warning: array subscript is above array bounds Apparently there's a problem with the optimized memcpy for x86 with this code: static char const langids[4] = {4, USB_DT_STRING, 0x09, 0x04}; len = min_t(unsigned, len, sizeof(langids)); memcpy(data, langids, len); return len; gcc 4.4 is trying to optimize the memcpy, but it's not able to realize that 'len' will always be <= 4 and the memcpy will not exceed langids. One way to solve this is by replacing len with the min_t expression: memcpy(data, langids, min_t(unsigned, len, sizeof(langids))); However, that looks ugly and we need the expression again for the return. Another way is to remove 'const' from langids. AFAIK the code is perfectly correct as it is, I think the fact that gcc 4.4 complains is a bug on gcc side. Cheers. -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
