Re: [next:akpm 129/309] net/core/sock.c:274:36: error: initializer element is not constant
From: John David Anglin
Date: Mon Jul 23 2012 - 11:19:49 EST
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@xxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
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
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John David Anglin dave.anglin@xxxxxxxx
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