[patch] x86, fix rwsem build bug on CONFIG_M386=y

[Ingo Molnar <mingo@elte.hu>]

* Adrian Bunk <bunk@stusta.de> wrote:

> This email lists some known regressions in 2.6.19-rc1 compared to 
> 2.6.18.

thanks Adrian - this list is extremely useful in my opinion! Please keep 
up the good work.

> Subject    : CONFIG_M386=y rwsem compile error
> References : http://lkml.org/lkml/2006/10/3/240
> Submitter  : Klaus Knopper <knopper@knopper.net>
> Guilty     : Andi Kleen <ak@suse.de>
>              commit add659bf8aa92f8b3f01a8c0220557c959507fb1
> Status     : unknown

find the fix below.

-------------------->
Subject: [patch] x86, fix rwsem build bug on CONFIG_M386=y
From: Ingo Molnar <mingo@elte.hu>

CONFIG_M386 turns on spinlock-based generic rwsems - which surprises the 
semaphore.S rwsem stubs. Tested both with and without CONFIG_M386.

Reported-by: Klaus Knopper <knopper@knopper.net>
Triaged-by: Adrian Bunk <bunk@stusta.de>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/i386/lib/semaphore.S |    3 +++
 1 file changed, 3 insertions(+)

Index: linux/arch/i386/lib/semaphore.S
===================================================================
--- linux.orig/arch/i386/lib/semaphore.S
+++ linux/arch/i386/lib/semaphore.S
@@ -152,6 +152,8 @@ ENTRY(__read_lock_failed)
 
 #endif
 
+#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
+
 /* Fix up special calling conventions */
 ENTRY(call_rwsem_down_read_failed)
 	CFI_STARTPROC
@@ -214,3 +216,4 @@ ENTRY(call_rwsem_downgrade_wake)
 	CFI_ENDPROC
 	END(call_rwsem_downgrade_wake)
 
+#endif