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 --- mm/highmem.c | 62 ++++-------------------------------------------------------- 1 file changed, 4 insertions(+), 58 deletions(-) (limited to 'mm/highmem.c') diff --git a/mm/highmem.c b/mm/highmem.c index 7a0aa1be4993..781e754a75ac 100644 --- a/mm/highmem.c +++ b/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 -- cgit v1.2.3-58-ga151