On Monday 02 May 2016 16:32:25 Andrew Morton wrote: > On Tue, 03 May 2016 01:10:16 +0200 Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > On Monday 02 May 2016 16:02:18 Andrew Morton wrote: > > > On Mon, 02 May 2016 23:48:19 +0200 Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > > > > This is another attempt to avoid a regression in wwn_to_u64() after > > > > that started using get_unaligned_be64(), which in turn ran into a > > > > bug on gcc-4.9 through 6.1. > > > > > > I'm still getting a couple screenfuls of things like > > > > > > net/tipc/name_distr.c: In function 'tipc_named_process_backlog': > > > net/tipc/name_distr.c:330: warning: format '%u' expects type 'unsigned int', but argument 3 has type 'unsigned int' > > > net/tipc/name_distr.c:330: warning: format '%u' expects type 'unsigned int', but argument 4 has type 'unsigned int' > > > net/tipc/name_distr.c:330: warning: format '%u' expects type 'unsigned int', but argument 5 has type 'unsigned int' > > > net/tipc/name_distr.c:330: warning: format '%u' expects type 'unsigned int', but argument 7 has type 'unsigned int' > > > > I've built a few thousand kernels (arm32 with gcc-6.1) with the patch applied, > > but didn't see this one. What target architecture and compiler version produced > > this? Does it go away if you add a (__u32) cast? I don't even know what the > > warning is trying to tell me. > > heh, I didn't actually read it. > > Hopefully we can write this off as a gcc-4.4.4 glitch. 4.8.4 is OK. Ah, old compiler. I've tried gcc-4.3 now on ARM, and I don't get this warning (just a lot "may be used uninitialized"), but unlike gcc-4.4, my version doesn't actually get into the code path I have changed because __builtin_bswap32 was only introduced with 4.4. I don't have gcc-4.4 and 4.5 here, but the warning does show up with 4.6, 4.7 and 4.8: drivers/soc/sunxi/sunxi_sram.c: In function ‘sunxi_sram_show’: drivers/soc/sunxi/sunxi_sram.c:103:7: warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument 3 has type ‘unsigned int’ [-Wformat=] 4.8 is probably still common enough that we should try to address this. This change addresses the problem for me with ARM gcc-4.8, but adding two more type casts. This also makes the 16/32/64 bit swaps all look the same. I would expect this to also have the same effect on 4.4. Please fold into the previous patch. Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> diff --git a/include/uapi/linux/swab.h b/include/uapi/linux/swab.h index d737804af181..8f3a8f606fd9 100644 --- a/include/uapi/linux/swab.h +++ b/include/uapi/linux/swab.h @@ -97,7 +97,7 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val) * @x: value to byteswap */ #ifdef __HAVE_BUILTIN_BSWAP16__ -#define __swab16(x) __builtin_bswap16((__u16)(x)) +#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) #else #define __swab16(x) \ (__builtin_constant_p((__u16)(x)) ? \ @@ -110,7 +110,7 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val) * @x: value to byteswap */ #ifdef __HAVE_BUILTIN_BSWAP32__ -#define __swab32(x) __builtin_bswap32((__u32)(x)) +#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) #else #define __swab32(x) \ (__builtin_constant_p((__u32)(x)) ? \ -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
