[RFC][PATCH 0/5] mm, highmem: kmap_atomic rework -v2

[RFC][PATCH 0/5] mm, highmem: kmap_atomic rework -v2

[Peter Zijlstra]

Next version of the kmap_atomic rework using Andrew's fancy CPP trickery to
avoid having to convert the whole tree at once.

This is compile tested for i386-allmodconfig, frv, mips-sb1250-swarm,
powerpc-ppc6xx_defconfig, sparc32_defconfig, arm-omap3 (all with
HIGHEM=y).

Boot-tested with: i386-defconfig.

Not tested with:
 - tile, stock toolchain doesn't build tile targets
 - nm10300, the arch doesn't build with highmem to begin with


Is this something we can live with?

[RFC][PATCH 1/5] mm: strictly nested kmap_atomic

[Peter Zijlstra]

[-- Attachment #1: kmap-2.patch --]
[-- Type: text/plain, Size: 3735 bytes --]

Ensure kmap_atomic usage is strictly nested

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Rik van Riel <riel@redhat.com>
---
 crypto/async_tx/async_memcpy.c |    2 +-
 crypto/blkcipher.c             |    2 +-
 drivers/block/loop.c           |    4 ++--
 include/linux/highmem.h        |    4 ++--
 kernel/power/snapshot.c        |    4 ++--
 5 files changed, 8 insertions(+), 8 deletions(-)

Index: linux-2.6/crypto/async_tx/async_memcpy.c
===================================================================
--- linux-2.6.orig/crypto/async_tx/async_memcpy.c
+++ linux-2.6/crypto/async_tx/async_memcpy.c
@@ -83,8 +83,8 @@ async_memcpy(struct page *dest, struct p
 
 		memcpy(dest_buf, src_buf, len);
 
-		kunmap_atomic(dest_buf, KM_USER0);
 		kunmap_atomic(src_buf, KM_USER1);
+		kunmap_atomic(dest_buf, KM_USER0);
 
 		async_tx_sync_epilog(submit);
 	}
Index: linux-2.6/crypto/blkcipher.c
===================================================================
--- linux-2.6.orig/crypto/blkcipher.c
+++ linux-2.6/crypto/blkcipher.c
@@ -89,9 +89,9 @@ static inline unsigned int blkcipher_don
 		memcpy(walk->dst.virt.addr, walk->page, n);
 		blkcipher_unmap_dst(walk);
 	} else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
-		blkcipher_unmap_src(walk);
 		if (walk->flags & BLKCIPHER_WALK_DIFF)
 			blkcipher_unmap_dst(walk);
+		blkcipher_unmap_src(walk);
 	}
 
 	scatterwalk_advance(&walk->in, n);
Index: linux-2.6/drivers/block/loop.c
===================================================================
--- linux-2.6.orig/drivers/block/loop.c
+++ linux-2.6/drivers/block/loop.c
@@ -99,8 +99,8 @@ static int transfer_none(struct loop_dev
 	else
 		memcpy(raw_buf, loop_buf, size);
 
-	kunmap_atomic(raw_buf, KM_USER0);
 	kunmap_atomic(loop_buf, KM_USER1);
+	kunmap_atomic(raw_buf, KM_USER0);
 	cond_resched();
 	return 0;
 }
@@ -128,8 +128,8 @@ static int transfer_xor(struct loop_devi
 	for (i = 0; i < size; i++)
 		*out++ = *in++ ^ key[(i & 511) % keysize];
 
-	kunmap_atomic(raw_buf, KM_USER0);
 	kunmap_atomic(loop_buf, KM_USER1);
+	kunmap_atomic(raw_buf, KM_USER0);
 	cond_resched();
 	return 0;
 }
Index: linux-2.6/include/linux/highmem.h
===================================================================
--- linux-2.6.orig/include/linux/highmem.h
+++ linux-2.6/include/linux/highmem.h
@@ -191,8 +191,8 @@ static inline void copy_user_highpage(st
 	vfrom = kmap_atomic(from, KM_USER0);
 	vto = kmap_atomic(to, KM_USER1);
 	copy_user_page(vto, vfrom, vaddr, to);
-	kunmap_atomic(vfrom, KM_USER0);
 	kunmap_atomic(vto, KM_USER1);
+	kunmap_atomic(vfrom, KM_USER0);
 }
 
 #endif
@@ -204,8 +204,8 @@ static inline void copy_highpage(struct 
 	vfrom = kmap_atomic(from, KM_USER0);
 	vto = kmap_atomic(to, KM_USER1);
 	copy_page(vto, vfrom);
-	kunmap_atomic(vfrom, KM_USER0);
 	kunmap_atomic(vto, KM_USER1);
+	kunmap_atomic(vfrom, KM_USER0);
 }
 
 #endif /* _LINUX_HIGHMEM_H */
Index: linux-2.6/kernel/power/snapshot.c
===================================================================
--- linux-2.6.orig/kernel/power/snapshot.c
+++ linux-2.6/kernel/power/snapshot.c
@@ -978,8 +978,8 @@ static void copy_data_page(unsigned long
 		src = kmap_atomic(s_page, KM_USER0);
 		dst = kmap_atomic(d_page, KM_USER1);
 		do_copy_page(dst, src);
-		kunmap_atomic(src, KM_USER0);
 		kunmap_atomic(dst, KM_USER1);
+		kunmap_atomic(src, KM_USER0);
 	} else {
 		if (PageHighMem(d_page)) {
 			/* Page pointed to by src may contain some kernel
@@ -2253,8 +2253,8 @@ swap_two_pages_data(struct page *p1, str
 	memcpy(buf, kaddr1, PAGE_SIZE);
 	memcpy(kaddr1, kaddr2, PAGE_SIZE);
 	memcpy(kaddr2, buf, PAGE_SIZE);
-	kunmap_atomic(kaddr1, KM_USER0);
 	kunmap_atomic(kaddr2, KM_USER1);
+	kunmap_atomic(kaddr1, KM_USER0);
 }
 
 /**

Re: [RFC][PATCH 1/5] mm: strictly nested kmap_atomic

[David Howells]

Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> Ensure kmap_atomic usage is strictly nested
> 
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Reviewed-by: Rik van Riel <riel@redhat.com>

Acked-by: David Howells <dhowells@redhat.com>

[RFC][PATCH 2/5] mm: stack based kmap_atomic

[Peter Zijlstra]

[-- Attachment #1: kmap-1.patch --]
[-- Type: text/plain, Size: 48577 bytes --]

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 down-side 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:
  - tile:    lack of upstream toolchain
  - nm10300: the arch doesn't actually build with highmem to begin with ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 arch/arm/include/asm/highmem.h       |    6 +-
 arch/arm/mm/highmem.c                |   23 +++++----
 arch/frv/include/asm/highmem.h       |   25 ++--------
 arch/frv/mb93090-mb00/pci-dma.c      |    4 -
 arch/frv/mm/cache-page.c             |    8 +--
 arch/frv/mm/highmem.c                |   51 +++++++++++++++++++++
 arch/mips/include/asm/highmem.h      |   18 ++-----
 arch/mips/mm/highmem.c               |   50 +++++++++++---------
 arch/mn10300/include/asm/highmem.h   |   42 ++++++++++-------
 arch/powerpc/include/asm/highmem.h   |    9 +--
 arch/powerpc/mm/highmem.c            |   35 ++++++++------
 arch/sparc/include/asm/highmem.h     |    4 -
 arch/sparc/mm/highmem.c              |   48 +++++++++++--------
 arch/tile/include/asm/highmem.h      |   10 ++--
 arch/tile/mm/highmem.c               |   85 +++++++++--------------------------
 arch/x86/include/asm/highmem.h       |   11 ++--
 arch/x86/include/asm/iomap.h         |    4 -
 arch/x86/kernel/crash_dump_32.c      |    2 
 arch/x86/mm/highmem_32.c             |   74 ++++++++++++++++--------------
 arch/x86/mm/iomap_32.c               |   45 ++++++++++--------
 drivers/gpu/drm/i915/i915_gem.c      |    9 +--
 drivers/gpu/drm/i915/i915_irq.c      |    5 --
 drivers/gpu/drm/i915/intel_overlay.c |    5 --
 drivers/gpu/drm/ttm/ttm_bo_util.c    |    8 +--
 include/linux/highmem.h              |   61 ++++++++++++++++---------
 include/linux/io-mapping.h           |   14 ++---
 mm/highmem.c                         |   62 +------------------------
 27 files changed, 357 insertions(+), 361 deletions(-)

Index: linux-2.6/arch/arm/mm/highmem.c
===================================================================
--- linux-2.6.orig/arch/arm/mm/highmem.c
+++ linux-2.6/arch/arm/mm/highmem.c
@@ -36,18 +36,17 @@ void kunmap(struct page *page)
 }
 EXPORT_SYMBOL(kunmap);
 
-void *kmap_atomic(struct page *page, enum km_type type)
+void *__kmap_atomic(struct page *page)
 {
 	unsigned int idx;
 	unsigned long vaddr;
 	void *kmap;
+	int type;
 
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
 
-	debug_kmap_atomic(type);
-
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
 	 * There is no cache coherency issue when non VIVT, so force the
@@ -61,6 +60,8 @@ void *kmap_atomic(struct page *page, enu
 	if (kmap)
 		return kmap;
 
+	type = kmap_atomic_idx_push();
+
 	idx = type + KM_TYPE_NR * smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
@@ -80,14 +81,17 @@ void *kmap_atomic(struct page *page, enu
 
 	return (void *)vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(__kmap_atomic);
 
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	unsigned int idx = type + KM_TYPE_NR * smp_processor_id();
+	int idx, type;
 
 	if (kvaddr >= (void *)FIXADDR_START) {
+		type = kmap_atomic_idx_pop();
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
 		if (cache_is_vivt())
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
@@ -103,15 +107,16 @@ void kunmap_atomic_notypecheck(void *kva
 	}
 	pagefault_enable();
 }
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
+EXPORT_SYMBOL(__kunmap_atomic);
 
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+void *kmap_atomic_pfn(unsigned long pfn)
 {
-	unsigned int idx;
 	unsigned long vaddr;
+	int idx, type;
 
 	pagefault_disable();
 
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
Index: linux-2.6/arch/frv/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/frv/include/asm/highmem.h
+++ linux-2.6/arch/frv/include/asm/highmem.h
@@ -112,12 +112,11 @@ extern struct page *kmap_atomic_to_page(
 	(void *) damlr;										  \
 })
 
-static inline void *kmap_atomic(struct page *page, enum km_type type)
+static inline void *kmap_atomic_primary(struct page *page, enum km_type type)
 {
 	unsigned long paddr;
 
 	pagefault_disable();
-	debug_kmap_atomic(type);
 	paddr = page_to_phys(page);
 
 	switch (type) {
@@ -125,14 +124,6 @@ static inline void *kmap_atomic(struct p
         case 1:		return __kmap_atomic_primary(1, paddr, 3);
         case 2:		return __kmap_atomic_primary(2, paddr, 4);
         case 3:		return __kmap_atomic_primary(3, paddr, 5);
-        case 4:		return __kmap_atomic_primary(4, paddr, 6);
-        case 5:		return __kmap_atomic_primary(5, paddr, 7);
-        case 6:		return __kmap_atomic_primary(6, paddr, 8);
-        case 7:		return __kmap_atomic_primary(7, paddr, 9);
-        case 8:		return __kmap_atomic_primary(8, paddr, 10);
-
-	case 9 ... 9 + NR_TLB_LINES - 1:
-		return __kmap_atomic_secondary(type - 9, paddr);
 
 	default:
 		BUG();
@@ -152,22 +143,13 @@ do {									\
 	asm volatile("tlbpr %0,gr0,#4,#1" : : "r"(vaddr) : "memory");	\
 } while(0)
 
-static inline void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+static inline void kunmap_atomic_primary(void *kvaddr, enum km_type type)
 {
 	switch (type) {
         case 0:		__kunmap_atomic_primary(0, 2);	break;
         case 1:		__kunmap_atomic_primary(1, 3);	break;
         case 2:		__kunmap_atomic_primary(2, 4);	break;
         case 3:		__kunmap_atomic_primary(3, 5);	break;
-        case 4:		__kunmap_atomic_primary(4, 6);	break;
-        case 5:		__kunmap_atomic_primary(5, 7);	break;
-        case 6:		__kunmap_atomic_primary(6, 8);	break;
-        case 7:		__kunmap_atomic_primary(7, 9);	break;
-        case 8:		__kunmap_atomic_primary(8, 10);	break;
-
-	case 9 ... 9 + NR_TLB_LINES - 1:
-		__kunmap_atomic_secondary(type - 9, kvaddr);
-		break;
 
 	default:
 		BUG();
@@ -175,6 +157,9 @@ static inline void kunmap_atomic_notypec
 	pagefault_enable();
 }
 
+void *__kmap_atomic(struct page *page);
+void __kunmap_atomic(void *kvaddr);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
Index: linux-2.6/arch/mips/mm/highmem.c
===================================================================
--- linux-2.6.orig/arch/mips/mm/highmem.c
+++ linux-2.6/arch/mips/mm/highmem.c
@@ -9,7 +9,7 @@ static pte_t *kmap_pte;
 
 unsigned long highstart_pfn, highend_pfn;
 
-void *__kmap(struct page *page)
+void *kmap(struct page *page)
 {
 	void *addr;
 
@@ -21,16 +21,16 @@ void *__kmap(struct page *page)
 
 	return addr;
 }
-EXPORT_SYMBOL(__kmap);
+EXPORT_SYMBOL(kmap);
 
-void __kunmap(struct page *page)
+void kunmap(struct page *page)
 {
 	BUG_ON(in_interrupt());
 	if (!PageHighMem(page))
 		return;
 	kunmap_high(page);
 }
-EXPORT_SYMBOL(__kunmap);
+EXPORT_SYMBOL(kunmap);
 
 /*
  * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
@@ -41,17 +41,17 @@ EXPORT_SYMBOL(__kunmap);
  * kmaps are appropriate for short, tight code paths only.
  */
 
-void *__kmap_atomic(struct page *page, enum km_type type)
+void *__kmap_atomic(struct page *page)
 {
-	enum fixed_addresses idx;
 	unsigned long vaddr;
+	int idx, type;
 
 	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
 
-	debug_kmap_atomic(type);
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
@@ -64,43 +64,47 @@ void *__kmap_atomic(struct page *page, e
 }
 EXPORT_SYMBOL(__kmap_atomic);
 
-void __kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
 {
-#ifdef CONFIG_DEBUG_HIGHMEM
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
+	int type;
 
 	if (vaddr < FIXADDR_START) { // FIXME
 		pagefault_enable();
 		return;
 	}
 
-	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+	type = kmap_atomic_idx_pop();
+#ifdef CONFIG_DEBUG_HIGHMEM
+	{
+		int idx = type + KM_TYPE_NR * smp_processor_id();
 
-	/*
-	 * force other mappings to Oops if they'll try to access
-	 * this pte without first remap it
-	 */
-	pte_clear(&init_mm, vaddr, kmap_pte-idx);
-	local_flush_tlb_one(vaddr);
-#endif
+		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
 
+		/*
+		 * force other mappings to Oops if they'll try to access
+		 * this pte without first remap it
+		 */
+		pte_clear(&init_mm, vaddr, kmap_pte-idx);
+		local_flush_tlb_one(vaddr);
+	}
+#endif
 	pagefault_enable();
 }
-EXPORT_SYMBOL(__kunmap_atomic_notypecheck);
+EXPORT_SYMBOL(__kunmap_atomic);
 
 /*
  * This is the same as kmap_atomic() but can map memory that doesn't
  * have a struct page associated with it.
  */
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+void *kmap_atomic_pfn(unsigned long pfn)
 {
-	enum fixed_addresses idx;
 	unsigned long vaddr;
+	int idx, type;
 
 	pagefault_disable();
 
-	debug_kmap_atomic(type);
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
@@ -109,7 +113,7 @@ void *kmap_atomic_pfn(unsigned long pfn,
 	return (void*) vaddr;
 }
 
-struct page *__kmap_atomic_to_page(void *ptr)
+struct page *kmap_atomic_to_page(void *ptr)
 {
 	unsigned long idx, vaddr = (unsigned long)ptr;
 	pte_t *pte;
Index: linux-2.6/arch/mn10300/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/mn10300/include/asm/highmem.h
+++ linux-2.6/arch/mn10300/include/asm/highmem.h
@@ -70,15 +70,16 @@ static inline void kunmap(struct page *p
  * be used in IRQ contexts, so in some (very limited) cases we need
  * it.
  */
-static inline unsigned long kmap_atomic(struct page *page, enum km_type type)
+static inline unsigned long __kmap_atomic(struct page *page)
 {
-	enum fixed_addresses idx;
 	unsigned long vaddr;
+	int idx, type;
 
+	pagefault_disable();
 	if (page < highmem_start_page)
 		return page_address(page);
 
-	debug_kmap_atomic(type);
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 #if HIGHMEM_DEBUG
@@ -91,26 +92,35 @@ static inline unsigned long kmap_atomic(
 	return vaddr;
 }
 
-static inline void kunmap_atomic_notypecheck(unsigned long vaddr, enum km_type type)
+static inline void __kunmap_atomic(unsigned long vaddr)
 {
-#if HIGHMEM_DEBUG
-	enum fixed_addresses idx = type + KM_TYPE_NR * smp_processor_id();
+	int type;
 
-	if (vaddr < FIXADDR_START) /* FIXME */
+	if (vaddr < FIXADDR_START) { /* FIXME */
+		pagefault_enable();
 		return;
+	}
 
-	if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
-		BUG();
+	type = kmap_atomic_idx_pop();
 
-	/*
-	 * force other mappings to Oops if they'll try to access
-	 * this pte without first remap it
-	 */
-	pte_clear(kmap_pte - idx);
-	__flush_tlb_one(vaddr);
+#if HIGHMEM_DEBUG
+	{
+		unsigned int idx;
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
+		if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
+			BUG();
+
+		/*
+		 * force other mappings to Oops if they'll try to access
+		 * this pte without first remap it
+		 */
+		pte_clear(kmap_pte - idx);
+		__flush_tlb_one(vaddr);
+	}
 #endif
+	pagefault_enable();
 }
-
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_HIGHMEM_H */
Index: linux-2.6/arch/powerpc/mm/highmem.c
===================================================================
--- linux-2.6.orig/arch/powerpc/mm/highmem.c
+++ linux-2.6/arch/powerpc/mm/highmem.c
@@ -29,17 +29,17 @@
  * be used in IRQ contexts, so in some (very limited) cases we need
  * it.
  */
-void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
-	unsigned int idx;
 	unsigned long vaddr;
+	int idx, type;
 
 	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
 
-	debug_kmap_atomic(type);
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
@@ -52,26 +52,33 @@ void *kmap_atomic_prot(struct page *page
 }
 EXPORT_SYMBOL(kmap_atomic_prot);
 
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
 {
-#ifdef CONFIG_DEBUG_HIGHMEM
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
+	int type;
 
 	if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
 		pagefault_enable();
 		return;
 	}
 
-	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+	type = kmap_atomic_idx_pop();
 
-	/*
-	 * force other mappings to Oops if they'll try to access
-	 * this pte without first remap it
-	 */
-	pte_clear(&init_mm, vaddr, kmap_pte-idx);
-	local_flush_tlb_page(NULL, vaddr);
+#ifdef CONFIG_DEBUG_HIGHMEM
+	{
+		unsigned int idx;
+
+		idx = type + KM_TYPE_NR * smp_processor_id();
+		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+
+		/*
+		 * force other mappings to Oops if they'll try to access
+		 * this pte without first remap it
+		 */
+		pte_clear(&init_mm, vaddr, kmap_pte-idx);
+		local_flush_tlb_page(NULL, vaddr);
+	}
 #endif
 	pagefault_enable();
 }
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
+EXPORT_SYMBOL(__kunmap_atomic);
Index: linux-2.6/arch/sparc/mm/highmem.c
===================================================================
--- linux-2.6.orig/arch/sparc/mm/highmem.c
+++ linux-2.6/arch/sparc/mm/highmem.c
@@ -29,17 +29,17 @@
 #include <asm/tlbflush.h>
 #include <asm/fixmap.h>
 
-void *kmap_atomic(struct page *page, enum km_type type)
+void *__kmap_atomic(struct page *page)
 {
-	unsigned long idx;
 	unsigned long vaddr;
+	long idx, type;
 
 	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
 
-	debug_kmap_atomic(type);
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 
@@ -63,44 +63,50 @@ void *kmap_atomic(struct page *page, enu
 
 	return (void*) vaddr;
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(__kmap_atomic);
 
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
 {
-#ifdef CONFIG_DEBUG_HIGHMEM
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	unsigned long idx = type + KM_TYPE_NR*smp_processor_id();
+	int type;
 
 	if (vaddr < FIXADDR_START) { // FIXME
 		pagefault_enable();
 		return;
 	}
 
-	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
+	type = kmap_atomic_idx_pop();
 
-/* XXX Fix - Anton */
+#ifdef CONFIG_DEBUG_HIGHMEM
+	{
+		unsigned long idx;
+
+		idx = type + KM_TYPE_NR * smp_processor_id();
+		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
+
+		/* XXX Fix - Anton */
 #if 0
-	__flush_cache_one(vaddr);
+		__flush_cache_one(vaddr);
 #else
-	flush_cache_all();
+		flush_cache_all();
 #endif
 
-	/*
-	 * force other mappings to Oops if they'll try to access
-	 * this pte without first remap it
-	 */
-	pte_clear(&init_mm, vaddr, kmap_pte-idx);
-/* XXX Fix - Anton */
+		/*
+		 * force other mappings to Oops if they'll try to access
+		 * this pte without first remap it
+		 */
+		pte_clear(&init_mm, vaddr, kmap_pte-idx);
+		/* XXX Fix - Anton */
 #if 0
-	__flush_tlb_one(vaddr);
+		__flush_tlb_one(vaddr);
 #else
-	flush_tlb_all();
+		flush_tlb_all();
 #endif
+	}
 #endif
-
 	pagefault_enable();
 }
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
+EXPORT_SYMBOL(__kunmap_atomic);
 
 /* We may be fed a pagetable here by ptep_to_xxx and others. */
 struct page *kmap_atomic_to_page(void *ptr)
Index: linux-2.6/arch/x86/mm/highmem_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/highmem_32.c
+++ linux-2.6/arch/x86/mm/highmem_32.c
@@ -9,6 +9,7 @@ void *kmap(struct page *page)
 		return page_address(page);
 	return kmap_high(page);
 }
+EXPORT_SYMBOL(kmap);
 
 void kunmap(struct page *page)
 {
@@ -18,6 +19,7 @@ void kunmap(struct page *page)
 		return;
 	kunmap_high(page);
 }
+EXPORT_SYMBOL(kunmap);
 
 /*
  * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
@@ -27,10 +29,10 @@ void kunmap(struct page *page)
  * However when holding an atomic kmap it is not legal to sleep, so atomic
  * kmaps are appropriate for short, tight code paths only.
  */
-void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
-	enum fixed_addresses idx;
 	unsigned long vaddr;
+	int idx, type;
 
 	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
 	pagefault_disable();
@@ -38,8 +40,7 @@ void *kmap_atomic_prot(struct page *page
 	if (!PageHighMem(page))
 		return page_address(page);
 
-	debug_kmap_atomic(type);
-
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 	BUG_ON(!pte_none(*(kmap_pte-idx)));
@@ -47,44 +48,57 @@ void *kmap_atomic_prot(struct page *page
 
 	return (void *)vaddr;
 }
+EXPORT_SYMBOL(kmap_atomic_prot);
+
+void *__kmap_atomic(struct page *page)
+{
+	return kmap_atomic_prot(page, kmap_prot);
+}
+EXPORT_SYMBOL(__kmap_atomic);
 
-void *kmap_atomic(struct page *page, enum km_type type)
+/*
+ * This is the same as kmap_atomic() but can map memory that doesn't
+ * have a struct page associated with it.
+ */
+void *kmap_atomic_pfn(unsigned long pfn)
 {
-	return kmap_atomic_prot(page, type, kmap_prot);
+	return kmap_atomic_prot_pfn(pfn, kmap_prot);
 }
+EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
 
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
 
-	/*
-	 * Force other mappings to Oops if they'll try to access this pte
-	 * without first remap it.  Keeping stale mappings around is a bad idea
-	 * also, in case the page changes cacheability attributes or becomes
-	 * a protected page in a hypervisor.
-	 */
-	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
+	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+		int idx, type;
+
+		type = kmap_atomic_idx_pop();
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+		WARN_ON_ONCE(idx !=
+			((vaddr - __fix_to_virt(FIX_KMAP_BEGIN)) >> PAGE_SHIFT));
+#endif
+		/*
+		 * Force other mappings to Oops if they'll try to access this
+		 * pte without first remap it.  Keeping stale mappings around
+		 * is a bad idea also, in case the page changes cacheability
+		 * attributes or becomes a protected page in a hypervisor.
+		 */
 		kpte_clear_flush(kmap_pte-idx, vaddr);
-	else {
+	}
 #ifdef CONFIG_DEBUG_HIGHMEM
+	else {
 		BUG_ON(vaddr < PAGE_OFFSET);
 		BUG_ON(vaddr >= (unsigned long)high_memory);
-#endif
 	}
+#endif
 
 	pagefault_enable();
 }
-
-/*
- * This is the same as kmap_atomic() but can map memory that doesn't
- * have a struct page associated with it.
- */
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
-{
-	return kmap_atomic_prot_pfn(pfn, type, kmap_prot);
-}
-EXPORT_SYMBOL_GPL(kmap_atomic_pfn); /* temporarily in use by i915 GEM until vmap */
+EXPORT_SYMBOL(__kunmap_atomic);
 
 struct page *kmap_atomic_to_page(void *ptr)
 {
@@ -98,12 +112,6 @@ struct page *kmap_atomic_to_page(void *p
 	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
 	return pte_page(*pte);
 }
-
-EXPORT_SYMBOL(kmap);
-EXPORT_SYMBOL(kunmap);
-EXPORT_SYMBOL(kmap_atomic);
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
-EXPORT_SYMBOL(kmap_atomic_prot);
 EXPORT_SYMBOL(kmap_atomic_to_page);
 
 void __init set_highmem_pages_init(void)
Index: linux-2.6/include/linux/highmem.h
===================================================================
--- linux-2.6.orig/include/linux/highmem.h
+++ linux-2.6/include/linux/highmem.h
@@ -28,18 +28,6 @@ static inline void invalidate_kernel_vma
 
 #include <asm/kmap_types.h>
 
-#ifdef CONFIG_DEBUG_HIGHMEM
-
-void debug_kmap_atomic(enum km_type type);
-
-#else
-
-static inline void debug_kmap_atomic(enum km_type type)
-{
-}
-
-#endif
-
 #ifdef CONFIG_HIGHMEM
 #include <asm/highmem.h>
 
@@ -49,6 +37,27 @@ extern unsigned long totalhigh_pages;
 
 void kmap_flush_unused(void);
 
+DECLARE_PER_CPU(int, __kmap_atomic_idx);
+
+static inline int kmap_atomic_idx_push(void)
+{
+	int idx = __get_cpu_var(__kmap_atomic_idx)++;
+#ifdef CONFIG_DEBUG_HIGHMEM
+	WARN_ON_ONCE(in_irq() && !irqs_disabled());
+	BUG_ON(idx > KM_TYPE_NR);
+#endif
+	return idx;
+}
+
+static inline int kmap_atomic_idx_pop(void)
+{
+	int idx = --__get_cpu_var(__kmap_atomic_idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+	BUG_ON(idx < 0);
+#endif
+	return idx;
+}
+
 #else /* CONFIG_HIGHMEM */
 
 static inline unsigned int nr_free_highpages(void) { return 0; }
@@ -66,19 +75,19 @@ static inline void kunmap(struct page *p
 {
 }
 
-static inline void *kmap_atomic(struct page *page, enum km_type idx)
+static inline void *__kmap_atomic(struct page *page)
 {
 	pagefault_disable();
 	return page_address(page);
 }
-#define kmap_atomic_prot(page, idx, prot)	kmap_atomic(page, idx)
+#define kmap_atomic_prot(page, prot)	__kmap_atomic(page)
 
-static inline void kunmap_atomic_notypecheck(void *addr, enum km_type idx)
+static inline void __kunmap_atomic(void *addr)
 {
 	pagefault_enable();
 }
 
-#define kmap_atomic_pfn(pfn, idx)	kmap_atomic(pfn_to_page(pfn), (idx))
+#define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
 #define kmap_atomic_to_page(ptr)	virt_to_page(ptr)
 
 #define kmap_flush_unused()	do {} while(0)
@@ -86,12 +95,20 @@ static inline void kunmap_atomic_notypec
 
 #endif /* CONFIG_HIGHMEM */
 
-/* Prevent people trying to call kunmap_atomic() as if it were kunmap() */
-/* kunmap_atomic() should get the return value of kmap_atomic, not the page. */
-#define kunmap_atomic(addr, idx) do { \
-		BUILD_BUG_ON(__same_type((addr), struct page *)); \
-		kunmap_atomic_notypecheck((addr), (idx)); \
-	} while (0)
+/*
+ * Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.
+ */
+#define kmap_atomic(page, args...) __kmap_atomic(page)
+
+/*
+ * Prevent people trying to call kunmap_atomic() as if it were kunmap()
+ * kunmap_atomic() should get the return value of kmap_atomic, not the page.
+ */
+#define kunmap_atomic(addr, args...) 				\
+do {								\
+	BUILD_BUG_ON(__same_type((addr), struct page *));	\
+	__kunmap_atomic(addr);					\
+} while (0)
 
 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 #ifndef clear_user_highpage
Index: linux-2.6/mm/highmem.c
===================================================================
--- linux-2.6.orig/mm/highmem.c
+++ linux-2.6/mm/highmem.c
@@ -42,6 +42,10 @@
 unsigned long totalhigh_pages __read_mostly;
 EXPORT_SYMBOL(totalhigh_pages);
 
+
+DEFINE_PER_CPU(int, __kmap_atomic_idx);
+EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx);
+
 unsigned int nr_free_highpages (void)
 {
 	pg_data_t *pgdat;
@@ -422,61 +426,3 @@ void __init page_address_init(void)
 }
 
 #endif	/* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */
-
-#ifdef CONFIG_DEBUG_HIGHMEM
-
-void debug_kmap_atomic(enum km_type type)
-{
-	static int warn_count = 10;
-
-	if (unlikely(warn_count < 0))
-		return;
-
-	if (unlikely(in_interrupt())) {
-		if (in_nmi()) {
-			if (type != KM_NMI && type != KM_NMI_PTE) {
-				WARN_ON(1);
-				warn_count--;
-			}
-		} else if (in_irq()) {
-			if (type != KM_IRQ0 && type != KM_IRQ1 &&
-			    type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ &&
-			    type != KM_BOUNCE_READ && type != KM_IRQ_PTE) {
-				WARN_ON(1);
-				warn_count--;
-			}
-		} else if (!irqs_disabled()) {	/* softirq */
-			if (type != KM_IRQ0 && type != KM_IRQ1 &&
-			    type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 &&
-			    type != KM_SKB_SUNRPC_DATA &&
-			    type != KM_SKB_DATA_SOFTIRQ &&
-			    type != KM_BOUNCE_READ) {
-				WARN_ON(1);
-				warn_count--;
-			}
-		}
-	}
-
-	if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||
-			type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ ||
-			type == KM_IRQ_PTE || type == KM_NMI ||
-			type == KM_NMI_PTE ) {
-		if (!irqs_disabled()) {
-			WARN_ON(1);
-			warn_count--;
-		}
-	} else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) {
-		if (irq_count() == 0 && !irqs_disabled()) {
-			WARN_ON(1);
-			warn_count--;
-		}
-	}
-#ifdef CONFIG_KGDB_KDB
-	if (unlikely(type == KM_KDB && atomic_read(&kgdb_active) == -1)) {
-		WARN_ON(1);
-		warn_count--;
-	}
-#endif /* CONFIG_KGDB_KDB */
-}
-
-#endif
Index: linux-2.6/arch/x86/mm/iomap_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/iomap_32.c
+++ linux-2.6/arch/x86/mm/iomap_32.c
@@ -48,21 +48,20 @@ int iomap_create_wc(resource_size_t base
 }
 EXPORT_SYMBOL_GPL(iomap_create_wc);
 
-void
-iomap_free(resource_size_t base, unsigned long size)
+void iomap_free(resource_size_t base, unsigned long size)
 {
 	io_free_memtype(base, base + size);
 }
 EXPORT_SYMBOL_GPL(iomap_free);
 
-void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
 {
-	enum fixed_addresses idx;
 	unsigned long vaddr;
+	int idx, type;
 
 	pagefault_disable();
 
-	debug_kmap_atomic(type);
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
@@ -72,10 +71,9 @@ void *kmap_atomic_prot_pfn(unsigned long
 }
 
 /*
- * Map 'pfn' using fixed map 'type' and protections 'prot'
+ * Map 'pfn' using protections 'prot'
  */
-void *
-iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
+void * iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
 {
 	/*
 	 * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS.
@@ -86,24 +84,33 @@ iomap_atomic_prot_pfn(unsigned long pfn,
 	if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC))
 		prot = PAGE_KERNEL_UC_MINUS;
 
-	return kmap_atomic_prot_pfn(pfn, type, prot);
+	return kmap_atomic_prot_pfn(pfn, prot);
 }
 EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
 
-void
-iounmap_atomic(void *kvaddr, enum km_type type)
+void iounmap_atomic(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
 
-	/*
-	 * Force other mappings to Oops if they'll try to access this pte
-	 * without first remap it.  Keeping stale mappings around is a bad idea
-	 * also, in case the page changes cacheability attributes or becomes
-	 * a protected page in a hypervisor.
-	 */
-	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
+	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+		int idx, type;
+
+		type = kmap_atomic_idx_pop();
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+		WARN_ON_ONCE(idx !=
+			((vaddr - __fix_to_virt(FIX_KMAP_BEGIN)) >> PAGE_SHIFT));
+#endif
+		/*
+		 * Force other mappings to Oops if they'll try to access this
+		 * pte without first remap it.  Keeping stale mappings around
+		 * is a bad idea also, in case the page changes cacheability
+		 * attributes or becomes a protected page in a hypervisor.
+		 */
 		kpte_clear_flush(kmap_pte-idx, vaddr);
+	}
 
 	pagefault_enable();
 }
Index: linux-2.6/arch/frv/mb93090-mb00/pci-dma.c
===================================================================
--- linux-2.6.orig/arch/frv/mb93090-mb00/pci-dma.c
+++ linux-2.6/arch/frv/mb93090-mb00/pci-dma.c
@@ -61,14 +61,14 @@ int dma_map_sg(struct device *dev, struc
 	dampr2 = __get_DAMPR(2);
 
 	for (i = 0; i < nents; i++) {
-		vaddr = kmap_atomic(sg_page(&sg[i]), __KM_CACHE);
+		vaddr = kmap_atomic_primary(sg_page(&sg[i]), __KM_CACHE);
 
 		frv_dcache_writeback((unsigned long) vaddr,
 				     (unsigned long) vaddr + PAGE_SIZE);
 
 	}
 
-	kunmap_atomic(vaddr, __KM_CACHE);
+	kunmap_atomic_primary(vaddr, __KM_CACHE);
 	if (dampr2) {
 		__set_DAMPR(2, dampr2);
 		__set_IAMPR(2, dampr2);
Index: linux-2.6/arch/frv/mm/cache-page.c
===================================================================
--- linux-2.6.orig/arch/frv/mm/cache-page.c
+++ linux-2.6/arch/frv/mm/cache-page.c
@@ -26,11 +26,11 @@ void flush_dcache_page(struct page *page
 
 	dampr2 = __get_DAMPR(2);
 
-	vaddr = kmap_atomic(page, __KM_CACHE);
+	vaddr = kmap_atomic_primary(page, __KM_CACHE);
 
 	frv_dcache_writeback((unsigned long) vaddr, (unsigned long) vaddr + PAGE_SIZE);
 
-	kunmap_atomic(vaddr, __KM_CACHE);
+	kunmap_atomic_primary(vaddr, __KM_CACHE);
 
 	if (dampr2) {
 		__set_DAMPR(2, dampr2);
@@ -54,12 +54,12 @@ void flush_icache_user_range(struct vm_a
 
 	dampr2 = __get_DAMPR(2);
 
-	vaddr = kmap_atomic(page, __KM_CACHE);
+	vaddr = kmap_atomic_primary(page, __KM_CACHE);
 
 	start = (start & ~PAGE_MASK) | (unsigned long) vaddr;
 	frv_cache_wback_inv(start, start + len);
 
-	kunmap_atomic(vaddr, __KM_CACHE);
+	kunmap_atomic_primary(vaddr, __KM_CACHE);
 
 	if (dampr2) {
 		__set_DAMPR(2, dampr2);
Index: linux-2.6/arch/frv/mm/highmem.c
===================================================================
--- linux-2.6.orig/arch/frv/mm/highmem.c
+++ linux-2.6/arch/frv/mm/highmem.c
@@ -36,3 +36,54 @@ struct page *kmap_atomic_to_page(void *p
 {
 	return virt_to_page(ptr);
 }
+
+void *__kmap_atomic(struct page *page)
+{
+	unsigned long paddr;
+	int type;
+
+	pagefault_disable();
+	type = kmap_atomic_idx_push();
+	paddr = page_to_phys(page);
+
+	switch (type) {
+	/*
+	 * The first 4 primary maps are reserved for architecture code
+	 */
+	case 0:		return __kmap_atomic_primary(4, paddr, 6);
+	case 1:		return __kmap_atomic_primary(5, paddr, 7);
+	case 2:		return __kmap_atomic_primary(6, paddr, 8);
+	case 3:		return __kmap_atomic_primary(7, paddr, 9);
+	case 4:		return __kmap_atomic_primary(8, paddr, 10);
+
+	case 5 ... 5 + NR_TLB_LINES - 1:
+		return __kmap_atomic_secondary(type - 5, paddr);
+
+	default:
+		BUG();
+		return NULL;
+	}
+}
+EXPORT_SYMBOL(__kmap_atomic);
+
+void __kunmap_atomic(void *kvaddr)
+{
+	int type = kmap_atomic_idx_pop();
+	switch (type) {
+	case 0:		__kunmap_atomic_primary(4, 6);	break;
+	case 1:		__kunmap_atomic_primary(5, 7);	break;
+	case 2:		__kunmap_atomic_primary(6, 8);	break;
+	case 3:		__kunmap_atomic_primary(7, 9);	break;
+	case 4:		__kunmap_atomic_primary(8, 10);	break;
+
+	case 5 ... 5 + NR_TLB_LINES - 1:
+		__kunmap_atomic_secondary(type - 5, kvaddr);
+		break;
+
+	default:
+		BUG();
+	}
+	pagefault_enable();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
+
Index: linux-2.6/arch/arm/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/arm/include/asm/highmem.h
+++ linux-2.6/arch/arm/include/asm/highmem.h
@@ -35,9 +35,9 @@ extern void kunmap_high_l1_vipt(struct p
 #ifdef CONFIG_HIGHMEM
 extern void *kmap(struct page *page);
 extern void kunmap(struct page *page);
-extern void *kmap_atomic(struct page *page, enum km_type type);
-extern void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type);
-extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
+extern void *__kmap_atomic(struct page *page);
+extern void __kunmap_atomic(void *kvaddr);
+extern void *kmap_atomic_pfn(unsigned long pfn);
 extern struct page *kmap_atomic_to_page(const void *ptr);
 #endif
 
Index: linux-2.6/arch/mips/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/mips/include/asm/highmem.h
+++ linux-2.6/arch/mips/include/asm/highmem.h
@@ -45,18 +45,12 @@ extern pte_t *pkmap_page_table;
 extern void * kmap_high(struct page *page);
 extern void kunmap_high(struct page *page);
 
-extern void *__kmap(struct page *page);
-extern void __kunmap(struct page *page);
-extern void *__kmap_atomic(struct page *page, enum km_type type);
-extern void __kunmap_atomic_notypecheck(void *kvaddr, enum km_type type);
-extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
-extern struct page *__kmap_atomic_to_page(void *ptr);
-
-#define kmap			__kmap
-#define kunmap			__kunmap
-#define kmap_atomic		__kmap_atomic
-#define kunmap_atomic_notypecheck		__kunmap_atomic_notypecheck
-#define kmap_atomic_to_page	__kmap_atomic_to_page
+extern void *kmap(struct page *page);
+extern void kunmap(struct page *page);
+extern void *__kmap_atomic(struct page *page);
+extern void __kunmap_atomic(void *kvaddr);
+extern void *kmap_atomic_pfn(unsigned long pfn);
+extern struct page *kmap_atomic_to_page(void *ptr);
 
 #define flush_cache_kmaps()	flush_cache_all()
 
Index: linux-2.6/arch/powerpc/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/highmem.h
+++ linux-2.6/arch/powerpc/include/asm/highmem.h
@@ -60,9 +60,8 @@ extern pte_t *pkmap_page_table;
 
 extern void *kmap_high(struct page *page);
 extern void kunmap_high(struct page *page);
-extern void *kmap_atomic_prot(struct page *page, enum km_type type,
-			      pgprot_t prot);
-extern void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type);
+extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
+extern void __kunmap_atomic(void *kvaddr);
 
 static inline void *kmap(struct page *page)
 {
@@ -80,9 +79,9 @@ static inline void kunmap(struct page *p
 	kunmap_high(page);
 }
 
-static inline void *kmap_atomic(struct page *page, enum km_type type)
+static inline void *__kmap_atomic(struct page *page)
 {
-	return kmap_atomic_prot(page, type, kmap_prot);
+	return kmap_atomic_prot(page, kmap_prot);
 }
 
 static inline struct page *kmap_atomic_to_page(void *ptr)
Index: linux-2.6/arch/sparc/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/sparc/include/asm/highmem.h
+++ linux-2.6/arch/sparc/include/asm/highmem.h
@@ -70,8 +70,8 @@ static inline void kunmap(struct page *p
 	kunmap_high(page);
 }
 
-extern void *kmap_atomic(struct page *page, enum km_type type);
-extern void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type);
+extern void *__kmap_atomic(struct page *page);
+extern void __kunmap_atomic(void *kvaddr);
 extern struct page *kmap_atomic_to_page(void *vaddr);
 
 #define flush_cache_kmaps()	flush_cache_all()
Index: linux-2.6/arch/tile/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/tile/include/asm/highmem.h
+++ linux-2.6/arch/tile/include/asm/highmem.h
@@ -60,12 +60,12 @@ void *kmap_fix_kpte(struct page *page, i
 /* This macro is used only in map_new_virtual() to map "page". */
 #define kmap_prot page_to_kpgprot(page)
 
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type);
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
-void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
+void *__kmap_atomic(struct page *page);
+void __kunmap_atomic(void *kvaddr);
+void *kmap_atomic_pfn(unsigned long pfn);
+void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
 struct page *kmap_atomic_to_page(void *ptr);
-void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot);
-void *kmap_atomic(struct page *page, enum km_type type);
+void *kmap_atomic_prot(struct page *page, pgprot_t prot);
 void kmap_atomic_fix_kpte(struct page *page, int finished);
 
 #define flush_cache_kmaps()	do { } while (0)
Index: linux-2.6/arch/tile/mm/highmem.c
===================================================================
--- linux-2.6.orig/arch/tile/mm/highmem.c
+++ linux-2.6/arch/tile/mm/highmem.c
@@ -56,50 +56,6 @@ void kunmap(struct page *page)
 }
 EXPORT_SYMBOL(kunmap);
 
-static void debug_kmap_atomic_prot(enum km_type type)
-{
-#ifdef CONFIG_DEBUG_HIGHMEM
-	static unsigned warn_count = 10;
-
-	if (unlikely(warn_count == 0))
-		return;
-
-	if (unlikely(in_interrupt())) {
-		if (in_irq()) {
-			if (type != KM_IRQ0 && type != KM_IRQ1 &&
-			    type != KM_BIO_SRC_IRQ &&
-			    /* type != KM_BIO_DST_IRQ && */
-			    type != KM_BOUNCE_READ) {
-				WARN_ON(1);
-				warn_count--;
-			}
-		} else if (!irqs_disabled()) {	/* softirq */
-			if (type != KM_IRQ0 && type != KM_IRQ1 &&
-			    type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 &&
-			    type != KM_SKB_SUNRPC_DATA &&
-			    type != KM_SKB_DATA_SOFTIRQ &&
-			    type != KM_BOUNCE_READ) {
-				WARN_ON(1);
-				warn_count--;
-			}
-		}
-	}
-
-	if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||
-	    type == KM_BIO_SRC_IRQ /* || type == KM_BIO_DST_IRQ */) {
-		if (!irqs_disabled()) {
-			WARN_ON(1);
-			warn_count--;
-		}
-	} else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) {
-		if (irq_count() == 0 && !irqs_disabled()) {
-			WARN_ON(1);
-			warn_count--;
-		}
-	}
-#endif
-}
-
 /*
  * Describe a single atomic mapping of a page on a given cpu at a
  * given address, and allow it to be linked into a list.
@@ -240,10 +196,10 @@ void kmap_atomic_fix_kpte(struct page *p
  * When holding an atomic kmap is is not legal to sleep, so atomic
  * kmaps are appropriate for short, tight code paths only.
  */
-void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
-	enum fixed_addresses idx;
 	unsigned long vaddr;
+	int idx, type;
 	pte_t *pte;
 
 	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
@@ -255,8 +211,7 @@ void *kmap_atomic_prot(struct page *page
 	if (!PageHighMem(page))
 		return page_address(page);
 
-	debug_kmap_atomic_prot(type);
-
+	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 	pte = kmap_get_pte(vaddr);
@@ -269,25 +224,31 @@ void *kmap_atomic_prot(struct page *page
 }
 EXPORT_SYMBOL(kmap_atomic_prot);
 
-void *kmap_atomic(struct page *page, enum km_type type)
+void *__kmap_atomic(struct page *page)
 {
 	/* PAGE_NONE is a magic value that tells us to check immutability. */
 	return kmap_atomic_prot(page, type, PAGE_NONE);
 }
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(__kmap_atomic);
 
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
 
-	/*
-	 * Force other mappings to Oops if they try to access this pte without
-	 * first remapping it.  Keeping stale mappings around is a bad idea.
-	 */
-	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) {
+	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
 		pte_t *pte = kmap_get_pte(vaddr);
 		pte_t pteval = *pte;
+		int idx, type;
+
+		type = kmap_atomic_idx_pop();
+		idx = type + KM_TYPE_NR*smp_processor_id();
+
+		/*
+		 * Force other mappings to Oops if they try to access this pte
+		 * without first remapping it.  Keeping stale mappings around
+		 * is a bad idea.
+		 */
 		BUG_ON(!pte_present(pteval) && !pte_migrating(pteval));
 		kmap_atomic_unregister(pte_page(pteval), vaddr);
 		kpte_clear_flush(pte, vaddr);
@@ -300,19 +261,19 @@ void kunmap_atomic_notypecheck(void *kva
 	arch_flush_lazy_mmu_mode();
 	pagefault_enable();
 }
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
+EXPORT_SYMBOL(__kunmap_atomic);
 
 /*
  * This API is supposed to allow us to map memory without a "struct page".
  * Currently we don't support this, though this may change in the future.
  */
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+void *kmap_atomic_pfn(unsigned long pfn)
 {
-	return kmap_atomic(pfn_to_page(pfn), type);
+	return kmap_atomic(pfn_to_page(pfn));
 }
-void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
 {
-	return kmap_atomic_prot(pfn_to_page(pfn), type, prot);
+	return kmap_atomic_prot(pfn_to_page(pfn), prot);
 }
 
 struct page *kmap_atomic_to_page(void *ptr)
Index: linux-2.6/arch/x86/include/asm/highmem.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/highmem.h
+++ linux-2.6/arch/x86/include/asm/highmem.h
@@ -59,11 +59,12 @@ extern void kunmap_high(struct page *pag
 
 void *kmap(struct page *page);
 void kunmap(struct page *page);
-void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot);
-void *kmap_atomic(struct page *page, enum km_type type);
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type);
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
-void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
+
+void *kmap_atomic_prot(struct page *page, pgprot_t prot);
+void *__kmap_atomic(struct page *page);
+void __kunmap_atomic(void *kvaddr);
+void *kmap_atomic_pfn(unsigned long pfn);
+void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
 struct page *kmap_atomic_to_page(void *ptr);
 
 #define flush_cache_kmaps()	do { } while (0)
Index: linux-2.6/arch/x86/kernel/crash_dump_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/crash_dump_32.c
+++ linux-2.6/arch/x86/kernel/crash_dump_32.c
@@ -61,7 +61,7 @@ ssize_t copy_oldmem_page(unsigned long p
 	if (!is_crashed_pfn_valid(pfn))
 		return -EFAULT;
 
-	vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
+	vaddr = kmap_atomic_pfn(pfn);
 
 	if (!userbuf) {
 		memcpy(buf, (vaddr + offset), csize);
Index: linux-2.6/arch/x86/include/asm/iomap.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/iomap.h
+++ linux-2.6/arch/x86/include/asm/iomap.h
@@ -27,10 +27,10 @@
 #include <asm/tlbflush.h>
 
 void *
-iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
+iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
 
 void
-iounmap_atomic(void *kvaddr, enum km_type type);
+iounmap_atomic(void *kvaddr);
 
 int
 iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot);
Index: linux-2.6/drivers/gpu/drm/i915/i915_gem.c
===================================================================
--- linux-2.6.orig/drivers/gpu/drm/i915/i915_gem.c
+++ linux-2.6/drivers/gpu/drm/i915/i915_gem.c
@@ -504,10 +504,10 @@ fast_user_write(struct io_mapping *mappi
 	char *vaddr_atomic;
 	unsigned long unwritten;
 
-	vaddr_atomic = io_mapping_map_atomic_wc(mapping, page_base, KM_USER0);
+	vaddr_atomic = io_mapping_map_atomic_wc(mapping, page_base);
 	unwritten = __copy_from_user_inatomic_nocache(vaddr_atomic + page_offset,
 						      user_data, length);
-	io_mapping_unmap_atomic(vaddr_atomic, KM_USER0);
+	io_mapping_unmap_atomic(vaddr_atomic);
 	if (unwritten)
 		return -EFAULT;
 	return 0;
@@ -3327,8 +3327,7 @@ i915_gem_object_pin_and_relocate(struct 
 		reloc_offset = obj_priv->gtt_offset + reloc->offset;
 		reloc_page = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
 						      (reloc_offset &
-						       ~(PAGE_SIZE - 1)),
-						      KM_USER0);
+						       ~(PAGE_SIZE - 1)));
 		reloc_entry = (uint32_t __iomem *)(reloc_page +
 						   (reloc_offset & (PAGE_SIZE - 1)));
 		reloc_val = target_obj_priv->gtt_offset + reloc->delta;
@@ -3339,7 +3338,7 @@ i915_gem_object_pin_and_relocate(struct 
 			  readl(reloc_entry), reloc_val);
 #endif
 		writel(reloc_val, reloc_entry);
-		io_mapping_unmap_atomic(reloc_page, KM_USER0);
+		io_mapping_unmap_atomic(reloc_page);
 
 		/* The updated presumed offset for this entry will be
 		 * copied back out to the user.
Index: linux-2.6/drivers/gpu/drm/i915/i915_irq.c
===================================================================
--- linux-2.6.orig/drivers/gpu/drm/i915/i915_irq.c
+++ linux-2.6/drivers/gpu/drm/i915/i915_irq.c
@@ -456,10 +456,9 @@ i915_error_object_create(struct drm_devi
 
 		local_irq_save(flags);
 		s = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
-					     reloc_offset,
-					     KM_IRQ0);
+					     reloc_offset);
 		memcpy_fromio(d, s, PAGE_SIZE);
-		io_mapping_unmap_atomic(s, KM_IRQ0);
+		io_mapping_unmap_atomic(s);
 		local_irq_restore(flags);
 
 		dst->pages[page] = d;
Index: linux-2.6/drivers/gpu/drm/i915/intel_overlay.c
===================================================================
--- linux-2.6.orig/drivers/gpu/drm/i915/intel_overlay.c
+++ linux-2.6/drivers/gpu/drm/i915/intel_overlay.c
@@ -185,8 +185,7 @@ static struct overlay_registers *intel_o
 
 	if (OVERLAY_NONPHYSICAL(overlay->dev)) {
 		regs = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
-						overlay->reg_bo->gtt_offset,
-						KM_USER0);
+						overlay->reg_bo->gtt_offset);
 
 		if (!regs) {
 			DRM_ERROR("failed to map overlay regs in GTT\n");
@@ -201,7 +200,7 @@ static struct overlay_registers *intel_o
 static void intel_overlay_unmap_regs_atomic(struct intel_overlay *overlay)
 {
 	if (OVERLAY_NONPHYSICAL(overlay->dev))
-		io_mapping_unmap_atomic(overlay->virt_addr, KM_USER0);
+		io_mapping_unmap_atomic(overlay->virt_addr);
 
 	overlay->virt_addr = NULL;
 
Index: linux-2.6/drivers/gpu/drm/ttm/ttm_bo_util.c
===================================================================
--- linux-2.6.orig/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ linux-2.6/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -170,7 +170,7 @@ static int ttm_copy_io_ttm_page(struct t
 	src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
 
 #ifdef CONFIG_X86
-	dst = kmap_atomic_prot(d, KM_USER0, prot);
+	dst = kmap_atomic_prot(d, prot);
 #else
 	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
 		dst = vmap(&d, 1, 0, prot);
@@ -183,7 +183,7 @@ static int ttm_copy_io_ttm_page(struct t
 	memcpy_fromio(dst, src, PAGE_SIZE);
 
 #ifdef CONFIG_X86
-	kunmap_atomic(dst, KM_USER0);
+	kunmap_atomic(dst);
 #else
 	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
 		vunmap(dst);
@@ -206,7 +206,7 @@ static int ttm_copy_ttm_io_page(struct t
 
 	dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
 #ifdef CONFIG_X86
-	src = kmap_atomic_prot(s, KM_USER0, prot);
+	src = kmap_atomic_prot(s, prot);
 #else
 	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
 		src = vmap(&s, 1, 0, prot);
@@ -219,7 +219,7 @@ static int ttm_copy_ttm_io_page(struct t
 	memcpy_toio(dst, src, PAGE_SIZE);
 
 #ifdef CONFIG_X86
-	kunmap_atomic(src, KM_USER0);
+	kunmap_atomic(src);
 #else
 	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL))
 		vunmap(src);
Index: linux-2.6/include/linux/io-mapping.h
===================================================================
--- linux-2.6.orig/include/linux/io-mapping.h
+++ linux-2.6/include/linux/io-mapping.h
@@ -81,8 +81,7 @@ io_mapping_free(struct io_mapping *mappi
 /* Atomic map/unmap */
 static inline void *
 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_mappi
 	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 *vaddr, int slot)
+io_mapping_unmap_atomic(void *vaddr)
 {
-	iounmap_atomic(vaddr, slot);
+	iounmap_atomic(vaddr);
 }
 
 static inline void *
@@ -137,14 +136,13 @@ io_mapping_free(struct io_mapping *mappi
 /* Atomic map/unmap */
 static inline void *
 io_mapping_map_atomic_wc(struct io_mapping *mapping,
-			 unsigned long offset,
-			 int slot)
+			 unsigned long offset)
 {
 	return ((char *) mapping) + offset;
 }
 
 static inline void
-io_mapping_unmap_atomic(void *vaddr, int slot)
+io_mapping_unmap_atomic(void *vaddr)
 {
 }
 

Re: [RFC][PATCH 2/5] mm: stack based kmap_atomic

[Chris Metcalf]

 Acked-by: Chris Metcalf <cmetcalf@tilera.com>
for the series.

Note that in patch 4/5 you can also remove the pte_*map_nested() #defines
in arch/tile/include/asm/pgtable.h.

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com

[RFC][PATCH 3/5] mm: Remove pte_*map_nested()

[Peter Zijlstra]

[-- Attachment #1: kmap-pte_nest.patch --]
[-- Type: text/plain, Size: 23747 bytes --]

Since we no longer need to provide KM_type, the whole pte_*map_nested()
API is now redundant, remove it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 arch/alpha/include/asm/pgtable.h         |    2 --
 arch/arm/include/asm/pgtable.h           |    6 ++----
 arch/arm/mm/fault-armv.c                 |    4 ++--
 arch/arm/mm/pgd.c                        |    4 ++--
 arch/avr32/include/asm/pgtable.h         |    2 --
 arch/cris/include/asm/pgtable.h          |    2 --
 arch/frv/include/asm/pgtable.h           |    9 ++-------
 arch/ia64/include/asm/pgtable.h          |    2 --
 arch/m32r/include/asm/pgtable.h          |    2 --
 arch/m68k/include/asm/motorola_pgtable.h |    2 --
 arch/m68k/include/asm/sun3_pgtable.h     |    2 --
 arch/microblaze/include/asm/pgtable.h    |    7 ++-----
 arch/mips/include/asm/pgtable-32.h       |    3 ---
 arch/mips/include/asm/pgtable-64.h       |    3 ---
 arch/mn10300/include/asm/pgtable.h       |    2 --
 arch/parisc/include/asm/pgtable.h        |    2 --
 arch/powerpc/include/asm/pgtable-ppc32.h |    8 ++------
 arch/powerpc/include/asm/pgtable-ppc64.h |    2 --
 arch/s390/include/asm/pgtable.h          |    2 --
 arch/score/include/asm/pgtable.h         |    3 ---
 arch/sh/include/asm/pgtable_32.h         |    3 ---
 arch/sh/include/asm/pgtable_64.h         |    2 --
 arch/sparc/include/asm/pgtable_32.h      |    3 ---
 arch/sparc/include/asm/pgtable_64.h      |    2 --
 arch/um/include/asm/pgtable.h            |    2 --
 arch/x86/include/asm/pgtable_32.h        |   14 ++------------
 arch/x86/include/asm/pgtable_64.h        |    2 --
 arch/xtensa/include/asm/pgtable.h        |    3 ---
 mm/memory.c                              |    4 ++--
 mm/mremap.c                              |    4 ++--
 30 files changed, 18 insertions(+), 90 deletions(-)

Index: linux-2.6/arch/alpha/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/alpha/include/asm/pgtable.h
+++ linux-2.6/arch/alpha/include/asm/pgtable.h
@@ -318,9 +318,7 @@ extern inline pte_t * pte_offset_kernel(
 }
 
 #define pte_offset_map(dir,addr)	pte_offset_kernel((dir),(addr))
-#define pte_offset_map_nested(dir,addr)	pte_offset_kernel((dir),(addr))
 #define pte_unmap(pte)			do { } while (0)
-#define pte_unmap_nested(pte)		do { } while (0)
 
 extern pgd_t swapper_pg_dir[1024];
 
Index: linux-2.6/arch/arm/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/arm/include/asm/pgtable.h
+++ linux-2.6/arch/arm/include/asm/pgtable.h
@@ -263,10 +263,8 @@ extern struct page *empty_zero_page;
 #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
 #define pte_offset_kernel(dir,addr)	(pmd_page_vaddr(*(dir)) + __pte_index(addr))
 
-#define pte_offset_map(dir,addr)	(__pte_map(dir, KM_PTE0) + __pte_index(addr))
-#define pte_offset_map_nested(dir,addr)	(__pte_map(dir, KM_PTE1) + __pte_index(addr))
-#define pte_unmap(pte)			__pte_unmap(pte, KM_PTE0)
-#define pte_unmap_nested(pte)		__pte_unmap(pte, KM_PTE1)
+#define pte_offset_map(dir,addr)	(__pte_map(dir) + __pte_index(addr))
+#define pte_unmap(pte)			__pte_unmap(pte)
 
 #ifndef CONFIG_HIGHPTE
 #define __pte_map(dir,km)	pmd_page_vaddr(*(dir))
Index: linux-2.6/arch/arm/mm/fault-armv.c
===================================================================
--- linux-2.6.orig/arch/arm/mm/fault-armv.c
+++ linux-2.6/arch/arm/mm/fault-armv.c
@@ -88,13 +88,13 @@ static int adjust_pte(struct vm_area_str
 	 * open-code the spin-locking.
 	 */
 	ptl = pte_lockptr(vma->vm_mm, pmd);
-	pte = pte_offset_map_nested(pmd, address);
+	pte = pte_offset_map(pmd, address);
 	spin_lock(ptl);
 
 	ret = do_adjust_pte(vma, address, pfn, pte);
 
 	spin_unlock(ptl);
-	pte_unmap_nested(pte);
+	pte_unmap(pte);
 
 	return ret;
 }
Index: linux-2.6/arch/arm/mm/pgd.c
===================================================================
--- linux-2.6.orig/arch/arm/mm/pgd.c
+++ linux-2.6/arch/arm/mm/pgd.c
@@ -57,9 +57,9 @@ pgd_t *get_pgd_slow(struct mm_struct *mm
 			goto no_pte;
 
 		init_pmd = pmd_offset(init_pgd, 0);
-		init_pte = pte_offset_map_nested(init_pmd, 0);
+		init_pte = pte_offset_map(init_pmd, 0);
 		set_pte_ext(new_pte, *init_pte, 0);
-		pte_unmap_nested(init_pte);
+		pte_unmap(init_pte);
 		pte_unmap(new_pte);
 	}
 
Index: linux-2.6/arch/avr32/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/avr32/include/asm/pgtable.h
+++ linux-2.6/arch/avr32/include/asm/pgtable.h
@@ -319,9 +319,7 @@ static inline pte_t pte_modify(pte_t pte
 #define pte_offset_kernel(dir, address)					\
 	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
 #define pte_offset_map(dir, address) pte_offset_kernel(dir, address)
-#define pte_offset_map_nested(dir, address) pte_offset_kernel(dir, address)
 #define pte_unmap(pte)		do { } while (0)
-#define pte_unmap_nested(pte)	do { } while (0)
 
 struct vm_area_struct;
 extern void update_mmu_cache(struct vm_area_struct * vma,
Index: linux-2.6/arch/cris/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/cris/include/asm/pgtable.h
+++ linux-2.6/arch/cris/include/asm/pgtable.h
@@ -248,10 +248,8 @@ static inline pgd_t * pgd_offset(const s
 	((pte_t *) pmd_page_vaddr(*(dir)) +  __pte_offset(address))
 #define pte_offset_map(dir, address) \
 	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
-#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
 
 #define pte_unmap(pte) do { } while (0)
-#define pte_unmap_nested(pte) do { } while (0)
 #define pte_pfn(x)		((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
 #define pfn_pte(pfn, prot)	__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 
Index: linux-2.6/arch/frv/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/frv/include/asm/pgtable.h
+++ linux-2.6/arch/frv/include/asm/pgtable.h
@@ -451,17 +451,12 @@ static inline pte_t pte_modify(pte_t pte
 
 #if defined(CONFIG_HIGHPTE)
 #define pte_offset_map(dir, address) \
-	((pte_t *)kmap_atomic(pmd_page(*(dir)),KM_PTE0) + pte_index(address))
-#define pte_offset_map_nested(dir, address) \
-	((pte_t *)kmap_atomic(pmd_page(*(dir)),KM_PTE1) + pte_index(address))
-#define pte_unmap(pte) kunmap_atomic(pte, KM_PTE0)
-#define pte_unmap_nested(pte) kunmap_atomic((pte), KM_PTE1)
+	((pte_t *)kmap_atomic(pmd_page(*(dir))) + pte_index(address))
+#define pte_unmap(pte) kunmap_atomic(pte)
 #else
 #define pte_offset_map(dir, address) \
 	((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
-#define pte_offset_map_nested(dir, address) pte_offset_map((dir), (address))
 #define pte_unmap(pte) do { } while (0)
-#define pte_unmap_nested(pte) do { } while (0)
 #endif
 
 /*
Index: linux-2.6/arch/ia64/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/ia64/include/asm/pgtable.h
+++ linux-2.6/arch/ia64/include/asm/pgtable.h
@@ -406,9 +406,7 @@ pgd_offset (const struct mm_struct *mm, 
 #define pte_index(addr)	 	(((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 #define pte_offset_kernel(dir,addr)	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(addr))
 #define pte_offset_map(dir,addr)	pte_offset_kernel(dir, addr)
-#define pte_offset_map_nested(dir,addr)	pte_offset_map(dir, addr)
 #define pte_unmap(pte)			do { } while (0)
-#define pte_unmap_nested(pte)		do { } while (0)
 
 /* atomic versions of the some PTE manipulations: */
 
Index: linux-2.6/arch/m32r/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/m32r/include/asm/pgtable.h
+++ linux-2.6/arch/m32r/include/asm/pgtable.h
@@ -332,9 +332,7 @@ static inline void pmd_set(pmd_t * pmdp,
 	((pte_t *)pmd_page_vaddr(*(dir)) + pte_index(address))
 #define pte_offset_map(dir, address)	\
 	((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
-#define pte_offset_map_nested(dir, address)	pte_offset_map(dir, address)
 #define pte_unmap(pte)		do { } while (0)
-#define pte_unmap_nested(pte)	do { } while (0)
 
 /* Encode and de-code a swap entry */
 #define __swp_type(x)			(((x).val >> 2) & 0x1f)
Index: linux-2.6/arch/m68k/include/asm/motorola_pgtable.h
===================================================================
--- linux-2.6.orig/arch/m68k/include/asm/motorola_pgtable.h
+++ linux-2.6/arch/m68k/include/asm/motorola_pgtable.h
@@ -221,9 +221,7 @@ static inline pte_t *pte_offset_kernel(p
 }
 
 #define pte_offset_map(pmdp,address) ((pte_t *)__pmd_page(*pmdp) + (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))
-#define pte_offset_map_nested(pmdp, address) pte_offset_map(pmdp, address)
 #define pte_unmap(pte)		((void)0)
-#define pte_unmap_nested(pte)	((void)0)
 
 /*
  * Allocate and free page tables. The xxx_kernel() versions are
Index: linux-2.6/arch/m68k/include/asm/sun3_pgtable.h
===================================================================
--- linux-2.6.orig/arch/m68k/include/asm/sun3_pgtable.h
+++ linux-2.6/arch/m68k/include/asm/sun3_pgtable.h
@@ -219,9 +219,7 @@ static inline pte_t pgoff_to_pte(unsigne
 #define pte_offset_kernel(pmd, address) ((pte_t *) __pmd_page(*pmd) + pte_index(address))
 /* FIXME: should we bother with kmap() here? */
 #define pte_offset_map(pmd, address) ((pte_t *)kmap(pmd_page(*pmd)) + pte_index(address))
-#define pte_offset_map_nested(pmd, address) pte_offset_map(pmd, address)
 #define pte_unmap(pte) kunmap(pte)
-#define pte_unmap_nested(pte) kunmap(pte)
 
 /* Macros to (de)construct the fake PTEs representing swap pages. */
 #define __swp_type(x)		((x).val & 0x7F)
Index: linux-2.6/arch/microblaze/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/microblaze/include/asm/pgtable.h
+++ linux-2.6/arch/microblaze/include/asm/pgtable.h
@@ -497,12 +497,9 @@ static inline pmd_t *pmd_offset(pgd_t *d
 #define pte_offset_kernel(dir, addr)	\
 	((pte_t *) pmd_page_kernel(*(dir)) + pte_index(addr))
 #define pte_offset_map(dir, addr)		\
-	((pte_t *) kmap_atomic(pmd_page(*(dir)), KM_PTE0) + pte_index(addr))
-#define pte_offset_map_nested(dir, addr)	\
-	((pte_t *) kmap_atomic(pmd_page(*(dir)), KM_PTE1) + pte_index(addr))
+	((pte_t *) kmap_atomic(pmd_page(*(dir))) + pte_index(addr))
 
-#define pte_unmap(pte)		kunmap_atomic(pte, KM_PTE0)
-#define pte_unmap_nested(pte)	kunmap_atomic(pte, KM_PTE1)
+#define pte_unmap(pte)		kunmap_atomic(pte)
 
 /* Encode and decode a nonlinear file mapping entry */
 #define PTE_FILE_MAX_BITS	29
Index: linux-2.6/arch/mips/include/asm/pgtable-32.h
===================================================================
--- linux-2.6.orig/arch/mips/include/asm/pgtable-32.h
+++ linux-2.6/arch/mips/include/asm/pgtable-32.h
@@ -154,10 +154,7 @@ pfn_pte(unsigned long pfn, pgprot_t prot
 
 #define pte_offset_map(dir, address)                                    \
 	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
-#define pte_offset_map_nested(dir, address)                             \
-	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 #define pte_unmap(pte) ((void)(pte))
-#define pte_unmap_nested(pte) ((void)(pte))
 
 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 
Index: linux-2.6/arch/mips/include/asm/pgtable-64.h
===================================================================
--- linux-2.6.orig/arch/mips/include/asm/pgtable-64.h
+++ linux-2.6/arch/mips/include/asm/pgtable-64.h
@@ -257,10 +257,7 @@ static inline pmd_t *pmd_offset(pud_t * 
 	((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 #define pte_offset_map(dir, address)					\
 	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
-#define pte_offset_map_nested(dir, address)				\
-	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 #define pte_unmap(pte) ((void)(pte))
-#define pte_unmap_nested(pte) ((void)(pte))
 
 /*
  * Initialize a new pgd / pmd table with invalid pointers.
Index: linux-2.6/arch/mn10300/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/mn10300/include/asm/pgtable.h
+++ linux-2.6/arch/mn10300/include/asm/pgtable.h
@@ -457,9 +457,7 @@ static inline int set_kernel_exec(unsign
 
 #define pte_offset_map(dir, address) \
 	((pte_t *) page_address(pmd_page(*(dir))) + pte_index(address))
-#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
 #define pte_unmap(pte)		do {} while (0)
-#define pte_unmap_nested(pte)	do {} while (0)
 
 /*
  * The MN10300 has external MMU info in the form of a TLB: this is adapted from
Index: linux-2.6/arch/parisc/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/parisc/include/asm/pgtable.h
+++ linux-2.6/arch/parisc/include/asm/pgtable.h
@@ -397,9 +397,7 @@ static inline pte_t pte_modify(pte_t pte
 #define pte_offset_kernel(pmd, address) \
 	((pte_t *) pmd_page_vaddr(*(pmd)) + pte_index(address))
 #define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
-#define pte_offset_map_nested(pmd, address) pte_offset_kernel(pmd, address)
 #define pte_unmap(pte) do { } while (0)
-#define pte_unmap_nested(pte) do { } while (0)
 
 #define pte_unmap(pte)			do { } while (0)
 #define pte_unmap_nested(pte)		do { } while (0)
Index: linux-2.6/arch/powerpc/include/asm/pgtable-ppc32.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/pgtable-ppc32.h
+++ linux-2.6/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -308,12 +308,8 @@ static inline void __ptep_set_access_fla
 #define pte_offset_kernel(dir, addr)	\
 	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(addr))
 #define pte_offset_map(dir, addr)		\
-	((pte_t *) kmap_atomic(pmd_page(*(dir)), KM_PTE0) + pte_index(addr))
-#define pte_offset_map_nested(dir, addr)	\
-	((pte_t *) kmap_atomic(pmd_page(*(dir)), KM_PTE1) + pte_index(addr))
-
-#define pte_unmap(pte)		kunmap_atomic(pte, KM_PTE0)
-#define pte_unmap_nested(pte)	kunmap_atomic(pte, KM_PTE1)
+	((pte_t *) kmap_atomic(pmd_page(*(dir))) + pte_index(addr))
+#define pte_unmap(pte)		kunmap_atomic(pte)
 
 /*
  * Encode and decode a swap entry.
Index: linux-2.6/arch/powerpc/include/asm/pgtable-ppc64.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/pgtable-ppc64.h
+++ linux-2.6/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -193,9 +193,7 @@
   (((pte_t *) pmd_page_vaddr(*(dir))) + (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))
 
 #define pte_offset_map(dir,addr)	pte_offset_kernel((dir), (addr))
-#define pte_offset_map_nested(dir,addr)	pte_offset_kernel((dir), (addr))
 #define pte_unmap(pte)			do { } while(0)
-#define pte_unmap_nested(pte)		do { } while(0)
 
 /* to find an entry in a kernel page-table-directory */
 /* This now only contains the vmalloc pages */
Index: linux-2.6/arch/s390/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/s390/include/asm/pgtable.h
+++ linux-2.6/arch/s390/include/asm/pgtable.h
@@ -1048,9 +1048,7 @@ static inline pmd_t *pmd_offset(pud_t *p
 #define pte_offset(pmd, addr) ((pte_t *) pmd_deref(*(pmd)) + pte_index(addr))
 #define pte_offset_kernel(pmd, address) pte_offset(pmd,address)
 #define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
-#define pte_offset_map_nested(pmd, address) pte_offset_kernel(pmd, address)
 #define pte_unmap(pte) do { } while (0)
-#define pte_unmap_nested(pte) do { } while (0)
 
 /*
  * 31 bit swap entry format:
Index: linux-2.6/arch/score/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/score/include/asm/pgtable.h
+++ linux-2.6/arch/score/include/asm/pgtable.h
@@ -88,10 +88,7 @@ static inline void pmd_clear(pmd_t *pmdp
 
 #define pte_offset_map(dir, address)	\
 	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
-#define pte_offset_map_nested(dir, address)	\
-	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 #define pte_unmap(pte) ((void)(pte))
-#define pte_unmap_nested(pte) ((void)(pte))
 
 /*
  * Bits 9(_PAGE_PRESENT) and 10(_PAGE_FILE)are taken,
Index: linux-2.6/arch/sh/include/asm/pgtable_32.h
===================================================================
--- linux-2.6.orig/arch/sh/include/asm/pgtable_32.h
+++ linux-2.6/arch/sh/include/asm/pgtable_32.h
@@ -429,10 +429,7 @@ static inline pte_t pte_modify(pte_t pte
 #define pte_offset_kernel(dir, address) \
 	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
 #define pte_offset_map(dir, address)		pte_offset_kernel(dir, address)
-#define pte_offset_map_nested(dir, address)	pte_offset_kernel(dir, address)
-
 #define pte_unmap(pte)		do { } while (0)
-#define pte_unmap_nested(pte)	do { } while (0)
 
 #ifdef CONFIG_X2TLB
 #define pte_ERROR(e) \
Index: linux-2.6/arch/sh/include/asm/pgtable_64.h
===================================================================
--- linux-2.6.orig/arch/sh/include/asm/pgtable_64.h
+++ linux-2.6/arch/sh/include/asm/pgtable_64.h
@@ -84,9 +84,7 @@ static __inline__ void set_pte(pte_t *pt
 		((pte_t *) ((pmd_val(*(dir))) & PAGE_MASK) + pte_index((addr)))
 
 #define pte_offset_map(dir,addr)	pte_offset_kernel(dir, addr)
-#define pte_offset_map_nested(dir,addr)	pte_offset_kernel(dir, addr)
 #define pte_unmap(pte)		do { } while (0)
-#define pte_unmap_nested(pte)	do { } while (0)
 
 #ifndef __ASSEMBLY__
 #define IOBASE_VADDR	0xff000000
Index: linux-2.6/arch/sparc/include/asm/pgtable_32.h
===================================================================
--- linux-2.6.orig/arch/sparc/include/asm/pgtable_32.h
+++ linux-2.6/arch/sparc/include/asm/pgtable_32.h
@@ -304,10 +304,7 @@ BTFIXUPDEF_CALL(pte_t *, pte_offset_kern
  * and sun4c is guaranteed to have no highmem anyway.
  */
 #define pte_offset_map(d, a)		pte_offset_kernel(d,a)
-#define pte_offset_map_nested(d, a)	pte_offset_kernel(d,a)
-
 #define pte_unmap(pte)		do{}while(0)
-#define pte_unmap_nested(pte)	do{}while(0)
 
 /* Certain architectures need to do special things when pte's
  * within a page table are directly modified.  Thus, the following
Index: linux-2.6/arch/sparc/include/asm/pgtable_64.h
===================================================================
--- linux-2.6.orig/arch/sparc/include/asm/pgtable_64.h
+++ linux-2.6/arch/sparc/include/asm/pgtable_64.h
@@ -659,9 +659,7 @@ static inline unsigned long pte_special(
 	 ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))
 #define pte_offset_kernel		pte_index
 #define pte_offset_map			pte_index
-#define pte_offset_map_nested		pte_index
 #define pte_unmap(pte)			do { } while (0)
-#define pte_unmap_nested(pte)		do { } while (0)
 
 /* Actual page table PTE updates.  */
 extern void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, pte_t *ptep, pte_t orig);
Index: linux-2.6/arch/um/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/um/include/asm/pgtable.h
+++ linux-2.6/arch/um/include/asm/pgtable.h
@@ -338,9 +338,7 @@ static inline pte_t pte_modify(pte_t pte
 	((pte_t *) pmd_page_vaddr(*(dir)) +  pte_index(address))
 #define pte_offset_map(dir, address) \
 	((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
-#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
 #define pte_unmap(pte) do { } while (0)
-#define pte_unmap_nested(pte) do { } while (0)
 
 struct mm_struct;
 extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
Index: linux-2.6/arch/x86/include/asm/pgtable_32.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/pgtable_32.h
+++ linux-2.6/arch/x86/include/asm/pgtable_32.h
@@ -49,24 +49,14 @@ extern void set_pmd_pfn(unsigned long, u
 #endif
 
 #if defined(CONFIG_HIGHPTE)
-#define __KM_PTE			\
-	(in_nmi() ? KM_NMI_PTE : 	\
-	 in_irq() ? KM_IRQ_PTE :	\
-	 KM_PTE0)
 #define pte_offset_map(dir, address)					\
-	((pte_t *)kmap_atomic(pmd_page(*(dir)), __KM_PTE) +		\
+	((pte_t *)kmap_atomic(pmd_page(*(dir))) +		\
 	 pte_index((address)))
-#define pte_offset_map_nested(dir, address)				\
-	((pte_t *)kmap_atomic(pmd_page(*(dir)), KM_PTE1) +		\
-	 pte_index((address)))
-#define pte_unmap(pte) kunmap_atomic((pte), __KM_PTE)
-#define pte_unmap_nested(pte) kunmap_atomic((pte), KM_PTE1)
+#define pte_unmap(pte) kunmap_atomic((pte))
 #else
 #define pte_offset_map(dir, address)					\
 	((pte_t *)page_address(pmd_page(*(dir))) + pte_index((address)))
-#define pte_offset_map_nested(dir, address) pte_offset_map((dir), (address))
 #define pte_unmap(pte) do { } while (0)
-#define pte_unmap_nested(pte) do { } while (0)
 #endif
 
 /* Clear a kernel PTE and flush it from the TLB */
Index: linux-2.6/arch/x86/include/asm/pgtable_64.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/pgtable_64.h
+++ linux-2.6/arch/x86/include/asm/pgtable_64.h
@@ -127,9 +127,7 @@ static inline int pgd_large(pgd_t pgd) {
 
 /* x86-64 always has all page tables mapped. */
 #define pte_offset_map(dir, address) pte_offset_kernel((dir), (address))
-#define pte_offset_map_nested(dir, address) pte_offset_kernel((dir), (address))
 #define pte_unmap(pte) ((void)(pte))/* NOP */
-#define pte_unmap_nested(pte) ((void)(pte)) /* NOP */
 
 #define update_mmu_cache(vma, address, ptep) do { } while (0)
 
Index: linux-2.6/arch/xtensa/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/xtensa/include/asm/pgtable.h
+++ linux-2.6/arch/xtensa/include/asm/pgtable.h
@@ -324,10 +324,7 @@ ptep_set_wrprotect(struct mm_struct *mm,
 #define pte_offset_kernel(dir,addr) 					\
 	((pte_t*) pmd_page_vaddr(*(dir)) + pte_index(addr))
 #define pte_offset_map(dir,addr)	pte_offset_kernel((dir),(addr))
-#define pte_offset_map_nested(dir,addr)	pte_offset_kernel((dir),(addr))
-
 #define pte_unmap(pte)		do { } while (0)
-#define pte_unmap_nested(pte)	do { } while (0)
 
 
 /*
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -813,7 +813,7 @@ again:
 	dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
 	if (!dst_pte)
 		return -ENOMEM;
-	src_pte = pte_offset_map_nested(src_pmd, addr);
+	src_pte = pte_offset_map(src_pmd, addr);
 	src_ptl = pte_lockptr(src_mm, src_pmd);
 	spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
 	orig_src_pte = src_pte;
@@ -844,7 +844,7 @@ again:
 
 	arch_leave_lazy_mmu_mode();
 	spin_unlock(src_ptl);
-	pte_unmap_nested(orig_src_pte);
+	pte_unmap(orig_src_pte);
 	add_mm_rss_vec(dst_mm, rss);
 	pte_unmap_unlock(orig_dst_pte, dst_ptl);
 	cond_resched();
Index: linux-2.6/mm/mremap.c
===================================================================
--- linux-2.6.orig/mm/mremap.c
+++ linux-2.6/mm/mremap.c
@@ -101,7 +101,7 @@ static void move_ptes(struct vm_area_str
 	 * pte locks because exclusive mmap_sem prevents deadlock.
 	 */
 	old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
- 	new_pte = pte_offset_map_nested(new_pmd, new_addr);
+	new_pte = pte_offset_map(new_pmd, new_addr);
 	new_ptl = pte_lockptr(mm, new_pmd);
 	if (new_ptl != old_ptl)
 		spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
@@ -119,7 +119,7 @@ static void move_ptes(struct vm_area_str
 	arch_leave_lazy_mmu_mode();
 	if (new_ptl != old_ptl)
 		spin_unlock(new_ptl);
-	pte_unmap_nested(new_pte - 1);
+	pte_unmap(new_pte - 1);
 	pte_unmap_unlock(old_pte - 1, old_ptl);
 	if (mapping)
 		mutex_unlock(&mapping->i_mmap_lock);

[RFC][PATCH 4/5] perf, x86: Fix up kmap_atomic type

[Peter Zijlstra]

[-- Attachment #1: kmap-x86-perf.patch --]
[-- Type: text/plain, Size: 1045 bytes --]

Now that the KM_type stuff is history, clean up the compiler warning.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 arch/x86/kernel/cpu/perf_event.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -49,7 +49,6 @@ static unsigned long
 copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
 {
 	unsigned long offset, addr = (unsigned long)from;
-	int type = in_nmi() ? KM_NMI : KM_IRQ0;
 	unsigned long size, len = 0;
 	struct page *page;
 	void *map;
@@ -63,9 +62,9 @@ copy_from_user_nmi(void *to, const void 
 		offset = addr & (PAGE_SIZE - 1);
 		size = min(PAGE_SIZE - offset, n - len);
 
-		map = kmap_atomic(page, type);
+		map = kmap_atomic(page);
 		memcpy(to, map+offset, size);
-		kunmap_atomic(map, type);
+		kunmap_atomic(map);
 		put_page(page);
 
 		len  += size;

[RFC][PATCH 5/5] mm: highmem documentation

[Peter Zijlstra]

[-- Attachment #1: kmap-doc.patch --]
[-- Type: text/plain, Size: 4470 bytes --]

David asked if I could make a start at documenting some of the highmem issues.

Requested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 Documentation/vm/highmem.txt |   99 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

Index: linux-2.6/Documentation/vm/highmem.txt
===================================================================
--- /dev/null
+++ linux-2.6/Documentation/vm/highmem.txt
@@ -0,0 +1,99 @@
+
+ - What is highmem?
+
+Highmem comes about when the physical memory size approaches the virtual
+memory size. At that point it is impossible for the kernel to keep all of
+physical memory mapped. This means the kernel needs to start managing
+temporary maps of pieces of physical memory it wants to access.
+
+The part of (physical) memory not covered by a permanent map is what we
+call highmem. There's various architecture dependent constraints on where
+exactly that border lies.
+
+On i386 for example we chose to map the kernel into every process so as not
+to have to pay the full TLB invalidation costs for kernel entry/exit. This
+means the virtual memory space (of 32bits, 4G) will have to be divided
+between user and kernel space.
+
+The traditional split for architectures using this approach is 3:1, 3G for
+userspace and the top 1G for kernel space. This means that we can at most
+map 1G of physical memory at any one time, but because we need (virtual)
+space for other things; including these temporary maps to access the rest
+of physical memory; the actual direct map will typically be less (usually
+around ~896M).
+
+Other architectures that have mm context tagged TLBs can have a separate
+kernel and user maps -- however some hardware (like some ARMs) have limited
+virtual space when they use mm context tags.
+
+ - So what about these temporary maps?
+
+The kernel contains several ways of creating temporary maps:
+
+ * vmap        -- useful for mapping multiple pages into a contiguous
+                  virtual space; needs global synchronization to unmap.
+
+ * kmap        -- useful for mapping a single page; needs global
+		  synchronization, but is amortized somewhat. Is also
+		  prone to deadlocks when using in a nested fashion.
+                  [not recommended for new code]
+
+ * kmap_atomic -- useful for mapping a single page; cpu local invalidate
+                  makes it perform well, however since you need to stay
+                  on the cpu it requires atomicity (not allowed to sleep)
+                  which also allows for usage in interrupt contexts.
+
+
+
+ - Right, so about this kmap_atomic, when/how do I use it?
+
+Both are straight forward, you use it when you want to access the contents
+of a page that might be allocated from highmem (see __GFP_HIGHMEM), say a
+page-cache page:
+
+	struct page *page = find_get_page(mapping, offset);
+	void *vaddr = kmap_atomic(page);
+
+	memset(vaddr, 0, PAGE_SIZE);
+
+	kunmap_atomic(vaddr);
+
+Note that the kunmap_atomic() call takes the result of the kmap_atomic()
+call not the argument.
+
+If you need to map two pages because you want to copy from one page to
+another you need to keep the kmap_atomic calls strictly nested, like:
+
+	vaddr1 = kmap_atomic(page1);
+	vaddr2 = kmap_atomic(page2);
+
+	memcpy(vaddr1, vaddr2, PAGE_SIZE);
+
+	kunmap_atomic(vaddr2);
+	kunmap_atomic(vaddr1);
+
+
+
+ - So all this temporary mapping stuff, isn't that expensive?
+
+Yes, it is, get a 64bit machine.
+
+
+
+ - Seriously, so I can stick 64G in my i386-PAE machine, sweet!
+
+Well, yes you can, but Linux won't make you happy. Linux needs a page-frame
+structure for each page in the system and the pageframes need to live in
+the permanent map. That means that you can have 896M/sizeof(struct page)
+page-frames at most; with struct page being 32-bytes that would end up
+being something in the order of 112G worth of pages, however the kernel
+needs to store more than just page-frames in that memory.
+
+The general recommendation is that you don't use more than 8G on a 32-bit
+machine, although more might work for you and your workload you're pretty
+much on your own -- don't expect kernel developers to really care much if
+things come apart.
+
+Also, PAE makes your page-tables larger, which means slowdowns due to more
+data to traverse in TLB fills and the like. The advantage is that PAE has
+more PTE bits and can provide advanced features like NX and PAT.

Re: [RFC][PATCH 5/5] mm: highmem documentation

[David Howells]

Not bad.  How about the attached version?

David
---

			     ====================
			     HIGH MEMORY HANDLING
			     ====================

By: Peter Zijlstra <a.p.zijlstra@chello.nl>

Contents:

 (*) What is high memory?

 (*) Temporary virtual mappings.

 (*) Using kmap_atomic.

 (*) Cost of temporary mappings.

 (*) i386 PAE.


====================
WHAT IS HIGH MEMORY?
====================

High memory (highmem) is used when the size of physical memory approaches or
exceeds the maximum size of virtual memory.  At that point it becomes
impossible for the kernel to keep all of the available physical memory mapped
at all times.  This means the kernel needs to start using temporary mappings of
the pieces of physical memory that it wants to access.

The part of (physical) memory not covered by a permanent mapping is what we
refer to as 'highmem'.  There are various architecture dependent constraints on
where exactly that border lies.

In the i386 arch, for example, we choose to map the kernel into every process's
VM space so that we don't have to pay the full TLB invalidation costs for
kernel entry/exit.  This means the available virtual memory space (4GiB on
i386) has to be divided between user and kernel space.

The traditional split for architectures using this approach is 3:1, 3GiB for
userspace and the top 1GiB for kernel space:

		+--------+ 0xffffffff
		| Kernel |
		+--------+ 0xc0000000
		|        |
		| User   |
		|        |
		+--------+ 0x00000000

This means that the kernel can at most map 1GiB of physical memory at any one
time, but because we need virtual address space for other things - including
temporary maps to access the rest of the physical memory - the actual direct
map will typically be less (usually around ~896MiB).

Other architectures that have mm context tagged TLBs can have separate kernel
and user maps.  Some hardware (like some ARMs), however, have limited virtual
space when they use mm context tags.


==========================
TEMPORARY VIRTUAL MAPPINGS
==========================

The kernel contains several ways of creating temporary mappings:

 (*) vmap().  This can be used to make a long duration mapping of multiple
     physical pages into a contiguous virtual space.  It needs global
     synchronization to unmap.

 (*) kmap().  This permits a short duration mapping of a single page.  It needs
     global synchronization, but is amortized somewhat.  It is also prone to
     deadlocks when using in a nested fashion, and so it is not recommended for
     new code.

 (*) kmap_atomic().  This permits a very short duration mapping of a single
     page.  Since the mapping is restricted to the CPU that issued it, it
     performs well, but the issuing task is therefore required to stay on that
     CPU until it has finished, lest some other task displace its mappings.

     kmap_atomic() may also be used by interrupt contexts, since it is does not
     sleep and the caller may not sleep until after kunmap_atomic() is called.

     It may be assumed that k[un]map_atomic() won't fail.


=================
USING KMAP_ATOMIC
=================

When and where to use kmap_atomic() is straightforward.  It is used when code
wants to access the contents of a page that might be allocated from high memory
(see __GFP_HIGHMEM), for example a page in the pagecache.  The API has two
functions, and they can be used in a manner similar to the following:

	/* Find the page of interest. */
	struct page *page = find_get_page(mapping, offset);

	/* Gain access to the contents of that page. */
	void *vaddr = kmap_atomic(page);

	/* Do something to the contents of that page. */
	memset(vaddr, 0, PAGE_SIZE);

	/* Unmap that page. */
	kunmap_atomic(vaddr);

Note that the kunmap_atomic() call takes the result of the kmap_atomic() call
not the argument.

If you need to map two pages because you want to copy from one page to
another you need to keep the kmap_atomic calls strictly nested, like:

	vaddr1 = kmap_atomic(page1);
	vaddr2 = kmap_atomic(page2);

	memcpy(vaddr1, vaddr2, PAGE_SIZE);

	kunmap_atomic(vaddr2);
	kunmap_atomic(vaddr1);


==========================
COST OF TEMPORARY MAPPINGS
==========================

The cost of creating temporary mappings can be quite high.  The arch has to
manipulate the kernel's page tables, the data TLB and/or the MMU's registers.

If CONFIG_HIGHMEM is not set, then the kernel will try and create a mapping
simply with a bit of arithmetic that will convert the page struct address into
a pointer to the page contents rather than juggling mappings about.  In such a
case, the unmap operation may be a null operation.

If CONFIG_MMU is not set, then there can be no temporary mappings and no
highmem.  In such a case, the arithmetic approach will also be used.


========
i386 PAE
========

The i386 arch, under some circumstances, will permit you to stick up to 64GiB
of RAM into your 32-bit machine.  This has a number of consequences:

 (*) Linux needs a page-frame structure for each page in the system and the
     pageframes need to live in the permanent mapping, which means:

 (*) you can have 896M/sizeof(struct page) page-frames at most; with struct
     page being 32-bytes that would end up being something in the order of 112G
     worth of pages; the kernel, however, needs to store more than just
     page-frames in that memory...

 (*) PAE makes your page tables larger - which slows the system down as more
     data has to be accessed to traverse in TLB fills and the like.  One
     advantage is that PAE has more PTE bits and can provide advanced features
     like NX and PAT.

The general recommendation is that you don't use more than 8GiB on a 32-bit
machine - although more might work for you and your workload, you're pretty
much on your own - don't expect kernel developers to really care much if things
come apart.

Re: [RFC][PATCH 5/5] mm: highmem documentation

[Peter Zijlstra]

On Wed, 2010-09-01 at 14:26 +0100, David Howells wrote:
> Not bad.  How about the attached version?
> 
Ooh, shiny!! Thanks a bunch.