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/powerpc/mm/highmem.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) (limited to 'arch/powerpc/mm/highmem.c') diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c index 857d4173f9c6..b0848b462bbc 100644 --- a/arch/powerpc/mm/highmem.c +++ b/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, enum km_type type, pgprot_t prot) } 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); -- cgit v1.2.1