[uml-devel] [PATCH] um: use RWSEM_GENERIC_SPINLOCK on x86

[uml-devel] [PATCH] um: use RWSEM_GENERIC_SPINLOCK on x86

[Richard Weinberger]

Commit d12337 (rwsem: Remove redundant asmregparm annotation)
broke rwsem on UML.
As we cannot compile UML with -mregparm=3 and keeping asmregparm only
for UML is inadequate the easiest solution is using RWSEM_GENERIC_SPINLOCK.

Thanks to Thomas Gleixner for the idea.

Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Tested-by: Toralf Förster <toralf.foerster@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org> # .39.x
Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/um/Kconfig.x86 |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/um/Kconfig.x86 b/arch/um/Kconfig.x86
index a9da516..d57cf9c 100644
--- a/arch/um/Kconfig.x86
+++ b/arch/um/Kconfig.x86
@@ -29,10 +29,10 @@ config X86_64
 	def_bool 64BIT
 
 config RWSEM_XCHGADD_ALGORITHM
-	def_bool X86_XADD
+	def_bool X86_XADD && 64BIT
 
 config RWSEM_GENERIC_SPINLOCK
-	def_bool !X86_XADD
+	def_bool !X86_XADD || !64BIT
 
 config 3_LEVEL_PGTABLES
 	bool "Three-level pagetables (EXPERIMENTAL)" if !64BIT
-- 
1.7.4.2


------------------------------------------------------------------------------
What Every C/C++ and Fortran developer Should Know!
Read this article and learn how Intel has extended the reach of its 
next-generation tools to help Windows* and Linux* C/C++ and Fortran 
developers boost performance applications - including clusters. 
http://p.sf.net/sfu/intel-dev2devmay
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

Re: [PATCH] um: use RWSEM_GENERIC_SPINLOCK on x86

[Linus Torvalds]

On Mon, May 23, 2011 at 1:30 PM, Richard Weinberger <richard@nod.at> wrote:
>
>  config RWSEM_XCHGADD_ALGORITHM
> -       def_bool X86_XADD
> +       def_bool X86_XADD && 64BIT
>
>  config RWSEM_GENERIC_SPINLOCK
> -       def_bool !X86_XADD
> +       def_bool !X86_XADD || !64BIT

May I suggest just changing that second one to

  config RWSEM_GENERIC_SPINLOCK
      def_bool !RWSEM_XCHGADD_ALGORITHM

because I had to look twice just to make sure that they are inverses
of each other.

So why not make that inverse relationship more obvious?

                         Linus

Re: [PATCH] um: use RWSEM_GENERIC_SPINLOCK on x86

[Linus Torvalds]

On Mon, May 23, 2011 at 1:30 PM, Richard Weinberger <richard@nod.at> wrote:
>
>  config RWSEM_XCHGADD_ALGORITHM
> -       def_bool X86_XADD
> +       def_bool X86_XADD && 64BIT
>
>  config RWSEM_GENERIC_SPINLOCK
> -       def_bool !X86_XADD
> +       def_bool !X86_XADD || !64BIT

May I suggest just changing that second one to

  config RWSEM_GENERIC_SPINLOCK
      def_bool !RWSEM_XCHGADD_ALGORITHM

because I had to look twice just to make sure that they are inverses
of each other.

So why not make that inverse relationship more obvious?

                         Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/