[PATCH 2.6] missing _raw_write_trylock

[PATCH 2.6] missing _raw_write_trylock

[Jun Sun]

[-- Attachment #1: Type: text/plain, Size: 102 bytes --]

Please help me reviewing the code, because inline assembly bug is
always tricky and miserable.  

Jun

[-- Attachment #2: junk --]
[-- Type: text/plain, Size: 752 bytes --]

diff -Nru linux/include/asm-mips/spinlock.h.orig linux/include/asm-mips/spinlock.h
--- linux/include/asm-mips/spinlock.h.orig	2004-01-05 10:48:38.000000000 -0800
+++ linux/include/asm-mips/spinlock.h	2004-03-15 18:50:30.000000000 -0800
@@ -167,4 +167,28 @@
 	: "memory");
 }
 
+static inline int _raw_write_trylock(rwlock_t *rw)
+{
+	unsigned int tmp;
+	int ret;
+
+	__asm__ __volatile__(
+	".set\tnoreorder\t\t\t# _raw_write_trylock\n"
+	"li\t%2, 0\n\t"
+	"1:\tll\t%1, %3\n\t"
+	"bnez\t%1, 2f\n\t"
+	"lui\t%1, 0x8000\n\t"
+	"sc\t%1, %0\n\t"
+	"beqz\t%1, 1b\n\t"
+	"sync\n\t"
+	"li\t%2, 1\n\t"
+	".set\treorder\n"
+	"2:"
+	: "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
+	: "m" (rw->lock)
+	: "memory");
+
+	return ret;
+}
+
 #endif /* _ASM_SPINLOCK_H */

Re: [PATCH 2.6] missing _raw_write_trylock

[Steven J. Hill]

Jun Sun wrote:
> Please help me reviewing the code, because inline assembly bug is
> always tricky and miserable.  
>
Are you going to do a non-LLSC, or are we no longer concerned about
those?

-Steve

Re: [PATCH 2.6] missing _raw_write_trylock

[Jun Sun]

On Tue, Mar 16, 2004 at 10:11:18AM -0500, Steven J. Hill wrote:
> Jun Sun wrote:
> >Please help me reviewing the code, because inline assembly bug is
> >always tricky and miserable.  
> >
> Are you going to do a non-LLSC, or are we no longer concerned about
> those?
> 

For SMP machines we assume LLSC are present.  This function and its friends 
for SMP only.

Jun

Re: [PATCH 2.6] missing _raw_write_trylock

[Christoph Hellwig]

On Tue, Mar 16, 2004 at 09:50:00AM -0800, Jun Sun wrote:
> > Are you going to do a non-LLSC, or are we no longer concerned about
> > those?
> > 
> 
> For SMP machines we assume LLSC are present.  This function and its friends 
> for SMP only.

doesn't CONFIG_PREEMPT (*shudder*) need it is aswell?

Re: [PATCH 2.6] missing _raw_write_trylock

[Christopher G. Stach II]

    CONFIG_SMP and CONFIG_PREEMPT at the same time, as it's in
kernel/sched.c.

chris

On Tue, 2004-03-16 at 13:08, Christoph Hellwig wrote:
> On Tue, Mar 16, 2004 at 09:50:00AM -0800, Jun Sun wrote:
> > > Are you going to do a non-LLSC, or are we no longer concerned about
> > > those?
> > > 
> > 
> > For SMP machines we assume LLSC are present.  This function and its friends 
> > for SMP only.
> 
> doesn't CONFIG_PREEMPT (*shudder*) need it is aswell?
> 
>