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mm: stack based kmap_atomic()

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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>
This commit is contained in:
Peter Zijlstra 2010-10-26 14:21:51 -07:00 • committed by Linus Torvalds
parent 61ecdb801e
commit 3e4d3af501
28 changed files with 371 additions and 376 deletions
Download patch file Download diff file Expand all files Collapse all files

61
include/linux/highmem.h
View file

@ -28,18 +28,6 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
#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 *page)
{
}
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_notypecheck(void *addr, enum km_type idx)
#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

14
include/linux/io-mapping.h
View file

@ -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)
{
}