Messages in this thread |  | | | From | John David Anglin <> | | Subject | Re: [next:akpm 129/309] net/core/sock.c:274:36: error: initializer element is not constant | | Date | Mon, 23 Jul 2012 11:13:23 -0400 |
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On 23-Jul-12, at 8:29 AM, Fengguang Wu wrote:
> On Mon, Jul 23, 2012 at 12:42:58PM +0100, Mel Gorman wrote: >> On Mon, Jul 23, 2012 at 12:20:20PM +0100, James Bottomley wrote: >>> [Parisc list cc added] >>> On Mon, 2012-07-23 at 12:16 +0100, Mel Gorman wrote: >>>> On Mon, Jul 23, 2012 at 12:30:58AM +0800, Fengguang Wu wrote: >>>>> Hi Mel, >>>>> >>>>> To be frank, I don't quite understand this build failure.. >>>>> >>>>> tree: next/akpm akpm >>>>> head: 37e2ad4953983527f7bdb6831bf478eedcc84082 >>>>> commit: 799dc3a908b1df8b766c35aefc24c1b5356aa051 [129/309] >>>>> netvm: allow skb allocation to use PFMEMALLOC reserves >>>>> config: parisc-defconfig (attached as .config) >>>>> >>>>> All related error/warning messages: >>>>> >>>>> net/core/sock.c:274:36: error: initializer element is not constant >>>>> net/core/sock.c:274:36: error: (near initialization for >>>>> 'memalloc_socks') >>>>> net/core/sock.c:274:36: error: initializer element is not constant >>>>> >>>> >>>> It looks parisc specific so am adding some parisc because this >>>> builds but >>>> I am less sure if it is actually correct. If it's correct, it >>>> should be >>>> appear before the swap-over-nfs patches to avoid bisection >>>> problems. >>>> I've added some parisc folk for review. >>>> >>>> ---8<--- >>>> parisc: Redefine ATOMIC_INIT and ATOMIC64_INIT like other >>>> architectures >>>> >>>> The following build error occured during a parisc build with >>>> swap-over-NFS patches applied. >>>> >>>> net/core/sock.c:274:36: error: initializer element is not constant >>>> net/core/sock.c:274:36: error: (near initialization for >>>> 'memalloc_socks') >>>> net/core/sock.c:274:36: error: initializer element is not constant >>>> >>>> It's not obvious but this is due to how ATOMIC_INIT is defined on >>>> parisc. It should affect any user of STATIC_KEY_INIT_FALSE on that >>>> platform. >>>> >>>> This patch makes the definition of ATOMIC_INIT on parisc to look >>>> like >>>> other arches definition. >>>> >>>> Reported-by: Fengguang Wu <fengguang.wu@intel.com> >>>> Signed-off-by: Mel Gorman <mgorman@suse.de> >>>> --- >>>> arch/parisc/include/asm/atomic.h | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/ >>>> include/asm/atomic.h >>>> index 6c6defc..af9cf30 100644 >>>> --- a/arch/parisc/include/asm/atomic.h >>>> +++ b/arch/parisc/include/asm/atomic.h >>>> @@ -141,7 +141,7 @@ static __inline__ int >>>> __atomic_add_unless(atomic_t *v, int a, int u) >>>> >>>> #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0) >>>> >>>> -#define ATOMIC_INIT(i) ((atomic_t) { (i) }) >>>> +#define ATOMIC_INIT(i) { (i) } >>>> >>>> #define smp_mb__before_atomic_dec() smp_mb() >>>> #define smp_mb__after_atomic_dec() smp_mb() >>>> @@ -150,7 +150,7 @@ static __inline__ int >>>> __atomic_add_unless(atomic_t *v, int a, int u) >>>> >>>> #ifdef CONFIG_64BIT >>>> >>>> -#define ATOMIC64_INIT(i) ((atomic64_t) { (i) }) >>>> +#define ATOMIC64_INIT(i) { (i) } >>>> >>>> static __inline__ s64 >>>> __atomic64_add_return(s64 i, atomic64_t *v) >>> >>> OK, I don't understand this either ... why would not casting to the >>> appropriate type suddenly stop warning about the initialiser being >>> non >>> constant. It looks like some type of gcc bug to me. >>
Possibly, the cast causes the const attribute to be dropped...
>> I agree. I could not see any functional difference as such either >> but also >> could not figure out why gcc would get it right for some arches and >> not >> for others. > > Will gcc create a temporary (and hence non constant) value for the > conversion?
Parisc is a callee copies architecture. Thus, a structure passed as an argument may be copied to a temporary. This has been a source of numerous bugs as the majority of architectures do it the other way round.
It would be easier to see what's happening with preprocessed source.
> >>> Our toolchain >>> expert (Dave) hangs out on the parisc list ... he'll want to know >>> your >>> gcc -v. >>> >> >> I'm using the cross-compiler from >> ftp://ftp.kernel.org/pub/tools/crosstool/files/bin/x86_64/4.6.3/. I >> do >> not know what compiler Fengguang Wu was using. > > Yeah that's handy binaries and I'm using them in the x86 compile > servers. However this particular parisc-defconfig is compile tested in > an ia64 machine which is built from debian's gcc-4.7 source: > > Using built-in specs. > COLLECT_GCC=/opt/cross/bin/hppa-linux-gcc > COLLECT_LTO_WRAPPER=/opt/cross/libexec/gcc/hppa-linux/4.7/lto-wrapper > Target: hppa-linux > Configured with: /home/wfg/buildall/gcc-4.7-4.7.1/src/configure -- > target=hppa-linux --enable-targets=all --prefix=/opt/cross --enable- > lang > uages=c --without-headers --enable-sjlj-exceptions --with-system- > libunwind --disable-nls --disable-threads --disable-shared --disable- > libmudflap --disable-libssp --disable-libgomp --disable-decimal- > float --disable-libquadmath --enable- > checking=release Thread model: single > gcc version 4.7.1 (GCC) > > Thanks, > Fengguang > >> Using built-in specs. >> COLLECT_GCC=/home/mel/git-public/cross-compilers/gcc-4.6.3-nolibc/ >> hppa-linux/bin/hppa-linux-gcc >> COLLECT_LTO_WRAPPER=/home/mel/git-public/cross-compilers/gcc-4.6.3- >> nolibc/hppa-linux/bin/../libexec/gcc/hppa-linux/4.6.3/lto-wrapper >> Target: hppa-linux >> Configured with: /home/tony/buildall/src/gcc/configure >> --target=hppa-linux --host=x86_64-linux-gnu --build=x86_64-linux-gnu >> --enable-targets=all --prefix=/opt/cross/gcc-4.6.3-nolibc/hppa-linux/ >> --enable-languages=c --with-newlib --without-headers >> --enable-sjlj-exceptions --with-system-libunwind --disable-nls >> --disable-threads --disable-shared --disable-libmudflap --disable- >> libssp >> --disable-libgomp --disable-decimal-float --enable-checking=release >> --with-mpfr=/home/tony/buildall/src/sys-x86_64 >> --with-gmp=/home/tony/buildall/src/sys-x86_64 --disable-bootstrap >> --disable-libquadmath >> Thread model: single >> gcc version 4.6.3 (GCC) >> >> -- >> Mel Gorman >> SUSE Labs > -- > To unsubscribe from this list: send the line "unsubscribe linux- > parisc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
-- John David Anglin dave.anglin@bell.net
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