Re: [NET]: Shut up warnings in net/core/flow.c

From: Andrew Morton
Date: Wed Nov 23 2005 - 03:21:48 EST


Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx> wrote:
>
> tree e7ba0f1bc8764c36859e2cfa9421bb1d86f2e7f4
> parent b3a5225f31180322fd7d692fd4cf786702826b94
> author Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Wed, 23 Nov 2005 06:38:04 -0800
> committer David S. Miller <davem@xxxxxxxxxxxxx> Wed, 23 Nov 2005 06:38:04 -0800
>
> [NET]: Shut up warnings in net/core/flow.c
>
> Not really a network problem, more a !SMP issue.
>
> net/core/flow.c:295: warning: statement with no effect
>
> flow.c:295: smp_call_function(flow_cache_flush_per_cpu, &info, 1, 0);
>
> Fix this by converting the macro to an inline function, which
> also increases the typechecking for !SMP builds.

Nope, this will break !CONFIG_SMP builds. Quite a few places in the kernel
do not implement the ipi handler if !CONFIG_SMP.

diff -puN include/linux/smp.h~smp_call_function-must-be-a-macro include/linux/smp.h
--- devel/include/linux/smp.h~smp_call_function-must-be-a-macro 2005-11-23 00:14:19.000000000 -0800
+++ devel-akpm/include/linux/smp.h 2005-11-23 00:20:54.000000000 -0800
@@ -94,13 +94,7 @@ void smp_prepare_boot_cpu(void);
*/
#define raw_smp_processor_id() 0
#define hard_smp_processor_id() 0
-
-static inline int smp_call_function(void (*func) (void *info), void *info,
- int retry, int wait)
-{
- return 0;
-}
-
+#define smp_call_function(func,info,retry,wait) ({ 0; })
#define on_each_cpu(func,info,retry,wait) ({ func(info); 0; })
static inline void smp_send_reschedule(int cpu) { }
#define num_booting_cpus() 1
diff -puN net/core/flow.c~smp_call_function-must-be-a-macro net/core/flow.c
--- devel/net/core/flow.c~smp_call_function-must-be-a-macro 2005-11-23 00:17:40.000000000 -0800
+++ devel-akpm/net/core/flow.c 2005-11-23 00:17:47.000000000 -0800
@@ -292,7 +292,7 @@ void flow_cache_flush(void)
init_completion(&info.completion);

local_bh_disable();
- smp_call_function(flow_cache_flush_per_cpu, &info, 1, 0);
+ (void)smp_call_function(flow_cache_flush_per_cpu, &info, 1, 0);
flow_cache_flush_tasklet((unsigned long)&info);
local_bh_enable();

_

-
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