From: David S. Miller <davem@sunset.davemloft.net>
Date: Thu, 6 Apr 2006 23:54:33 +0000 (-0700)
Subject: [SPARC64]: smp_call_function() fixups...
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=aa1d1a0af6022f02fb601508d3feaabafd405299;p=openwrt%2Fstaging%2Fblogic.git

[SPARC64]: smp_call_function() fixups...

1) Take doc-book function comment from i386 implementation.
2) cacheline align call_lock, taken from powerpc
3) Need memory barrier after setting call_data
4) Remove timeout

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 8175a6968c6b..eb36f7988ff7 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -745,12 +745,21 @@ struct call_data_struct {
 	int wait;
 };
 
-static DEFINE_SPINLOCK(call_lock);
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
 static struct call_data_struct *call_data;
 
 extern unsigned long xcall_call_function;
 
-/*
+/**
+ * smp_call_function(): Run a function on all other CPUs.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: currently unused.
+ * @wait: If true, wait (atomically) until function has completed on other CPUs.
+ *
+ * Returns 0 on success, else a negative status code. Does not return until
+ * remote CPUs are nearly ready to execute <<func>> or are or have executed.
+ *
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
  */
@@ -759,7 +768,6 @@ static int smp_call_function_mask(void (*func)(void *info), void *info,
 {
 	struct call_data_struct data;
 	int cpus;
-	long timeout;
 
 	/* Can deadlock when called with interrupts disabled */
 	WARN_ON(irqs_disabled());
@@ -777,31 +785,18 @@ static int smp_call_function_mask(void (*func)(void *info), void *info,
 		goto out_unlock;
 
 	call_data = &data;
+	mb();
 
 	smp_cross_call_masked(&xcall_call_function, 0, 0, 0, mask);
 
-	/* 
-	 * Wait for other cpus to complete function or at
-	 * least snap the call data.
-	 */
-	timeout = 1000000;
-	while (atomic_read(&data.finished) != cpus) {
-		if (--timeout <= 0)
-			goto out_timeout;
-		barrier();
-		udelay(1);
-	}
+	/* Wait for response */
+	while (atomic_read(&data.finished) != cpus)
+		cpu_relax();
 
 out_unlock:
 	spin_unlock(&call_lock);
 
 	return 0;
-
-out_timeout:
-	spin_unlock(&call_lock);
-	printk("XCALL: Remote cpus not responding, ncpus=%d finished=%d\n",
-	       cpus, atomic_read(&data.finished));
-	return 0;
 }
 
 int smp_call_function(void (*func)(void *info), void *info,