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 <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>
diff --git a/arch/mn10300/include/asm/highmem.h b/arch/mn10300/include/asm/highmem.h
index b0b187a..f577ba2 100644
--- a/arch/mn10300/include/asm/highmem.h
+++ b/arch/mn10300/include/asm/highmem.h
@@ -70,15 +70,16 @@
* be used in IRQ contexts, so in some (very limited) cases we need
* it.
*/
-static inline unsigned long kmap_atomic(struct page *page, enum km_type type)
+static inline unsigned long __kmap_atomic(struct page *page)
{
- enum fixed_addresses idx;
unsigned long vaddr;
+ int idx, type;
+ pagefault_disable();
if (page < highmem_start_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);
#if HIGHMEM_DEBUG
@@ -91,26 +92,35 @@
return vaddr;
}
-static inline void kunmap_atomic_notypecheck(unsigned long vaddr, enum km_type type)
+static inline void __kunmap_atomic(unsigned long vaddr)
{
-#if HIGHMEM_DEBUG
- enum fixed_addresses idx = type + KM_TYPE_NR * smp_processor_id();
+ int type;
- if (vaddr < FIXADDR_START) /* FIXME */
+ if (vaddr < FIXADDR_START) { /* FIXME */
+ pagefault_enable();
return;
+ }
- if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
- BUG();
+ type = kmap_atomic_idx_pop();
- /*
- * force other mappings to Oops if they'll try to access
- * this pte without first remap it
- */
- pte_clear(kmap_pte - idx);
- __flush_tlb_one(vaddr);
+#if HIGHMEM_DEBUG
+ {
+ unsigned int idx;
+ idx = type + KM_TYPE_NR * smp_processor_id();
+
+ if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
+ BUG();
+
+ /*
+ * force other mappings to Oops if they'll try to access
+ * this pte without first remap it
+ */
+ pte_clear(kmap_pte - idx);
+ __flush_tlb_one(vaddr);
+ }
#endif
+ pagefault_enable();
}
-
#endif /* __KERNEL__ */
#endif /* _ASM_HIGHMEM_H */