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>

1 files changed, 6 insertions, 8 deletions

diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
index 7fb592793738..8cdcc2a199ad 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -81,8 +81,7 @@ io_mapping_free(struct io_mapping *mapping)
 /* Atomic map/unmap */
 static inline void __iomem *
 io_mapping_map_atomic_wc(struct io_mapping *mapping,
-                         unsigned long offset,
-                         int slot)
+                         unsigned long offset)
 {
         resource_size_t phys_addr;
         unsigned long pfn;
@@ -90,13 +89,13 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping,
         BUG_ON(offset >= mapping->size);
         phys_addr = mapping->base + offset;
         pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
-        return iomap_atomic_prot_pfn(pfn, slot, mapping->prot);
+        return iomap_atomic_prot_pfn(pfn, mapping->prot);
 }
 
 static inline void
-io_mapping_unmap_atomic(void __iomem *vaddr, int slot)
+io_mapping_unmap_atomic(void __iomem *vaddr)
 {
-        iounmap_atomic(vaddr, slot);
+        iounmap_atomic(vaddr);
 }
 
 static inline void __iomem *
@@ -137,14 +136,13 @@ io_mapping_free(struct io_mapping *mapping)
 /* Atomic map/unmap */
 static inline void __iomem *
 io_mapping_map_atomic_wc(struct io_mapping *mapping,
-                         unsigned long offset,
-                         int slot)
+                         unsigned long offset)
 {
         return ((char __force __iomem *) mapping) + offset;
 }
 
 static inline void
-io_mapping_unmap_atomic(void __iomem *vaddr, int slot)
+io_mapping_unmap_atomic(void __iomem *vaddr)
 {
 }