From 3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 26 Oct 2010 14:21:51 -0700 Subject: mm: stack based kmap_atomic() Keep the current interface but ignore the KM_type and use a stack based approach. The advantage is that we get rid of crappy code like: #define __KM_PTE \ (in_nmi() ? KM_NMI_PTE : \ in_irq() ? KM_IRQ_PTE : \ KM_PTE0) and in general can stop worrying about what context we're in and what kmap slots might be appropriate for that. The downside is that FRV kmap_atomic() gets more expensive. For now we use a CPP trick suggested by Andrew: #define kmap_atomic(page, args...) __kmap_atomic(page) to avoid having to touch all kmap_atomic() users in a single patch. [ not compiled on: - mn10300: the arch doesn't actually build with highmem to begin with ] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c] Acked-by: Rik van Riel Signed-off-by: Peter Zijlstra Acked-by: Chris Metcalf Cc: David Howells Cc: Hugh Dickins Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Steven Rostedt Cc: Russell King Cc: Ralf Baechle Cc: David Miller Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Dave Airlie Cc: Li Zefan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/mm/highmem.c | 50 +++++++++++++++++++++++++++----------------------- 1 file changed, 27 insertions(+), 23 deletions(-) (limited to 'arch/mips/mm') diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c index 6a2b1bf9ef11..1e69b1fb4b85 100644 --- a/arch/mips/mm/highmem.c +++ b/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, enum km_type type) } 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, enum km_type type) 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; -- cgit v1.2.3