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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

62
mm/highmem.c
View File

@@ -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