Re: [next:akpm 129/309] net/core/sock.c:274:36: error: initializerelement is not constant

From: James Bottomley
Date: Wed Jul 25 2012 - 01:10:57 EST


On Tue, 2012-07-24 at 17:08 -0400, John David Anglin wrote:
> Removing "(atomic_t)" from the define results in a constant expression.

OK, so this is what I'll queue for fixes:

From: Mel Gorman <mgorman@xxxxxxx> Date: Mon, 23 Jul 2012 12:16:19
Subject: [PATCH] [PARISC] Redefine ATOMIC_INIT and ATOMIC64_INIT to drop the casts

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

Dave Anglin says:
> Here is the line in sock.i:
>
> struct static_key memalloc_socks = ((struct static_key) { .enabled =
> ((atomic_t) { (0) }) });

The above line contains two compound literals. It also uses a designated
initializer to initialize the field enabled. A compound literal is not a
constant expression.

The location of the above statement isn't fully clear, but if a compound
literal occurs outside the body of a function, the initializer list must
consist of constant expressions.

Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>

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)


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