mm: stack based kmap_atomic()
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Tue, 26 Oct 2010 21:21:51 +0000 (14:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 26 Oct 2010 23:52:08 +0000 (16:52 -0700)
commit3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73
tree2ce507f7ec7275563653e52f18606aba4f99b7f1
parent61ecdb801ef2cd28e32442383106d7837d76deac
mm: stack based kmap_atomic()

Keep the current interface but ignore the KM_type and use a stack based
approach.

The advantage is that we get rid of crappy code like:

#define __KM_PTE \
(in_nmi() ? KM_NMI_PTE :  \
 in_irq() ? KM_IRQ_PTE : \
 KM_PTE0)

and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.

The downside is that FRV kmap_atomic() gets more expensive.

For now we use a CPP trick suggested by Andrew:

  #define kmap_atomic(page, args...) __kmap_atomic(page)

to avoid having to touch all kmap_atomic() users in a single patch.

[ not compiled on:
  - mn10300: the arch doesn't actually build with highmem to begin with ]

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
28 files changed:
arch/arm/include/asm/highmem.h
arch/arm/mm/highmem.c
arch/frv/include/asm/highmem.h
arch/frv/mb93090-mb00/pci-dma.c
arch/frv/mm/cache-page.c
arch/frv/mm/highmem.c
arch/mips/include/asm/highmem.h
arch/mips/mm/highmem.c
arch/mn10300/include/asm/highmem.h
arch/powerpc/include/asm/highmem.h
arch/powerpc/mm/highmem.c
arch/sparc/include/asm/highmem.h
arch/sparc/mm/highmem.c
arch/tile/include/asm/highmem.h
arch/tile/mm/highmem.c
arch/x86/include/asm/highmem.h
arch/x86/include/asm/iomap.h
arch/x86/kernel/crash_dump_32.c
arch/x86/mm/highmem_32.c
arch/x86/mm/iomap_32.c
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/i915_irq.c
drivers/gpu/drm/i915/intel_overlay.c
drivers/gpu/drm/nouveau/nouveau_bios.c
drivers/gpu/drm/ttm/ttm_bo_util.c
include/linux/highmem.h
include/linux/io-mapping.h
mm/highmem.c