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/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index 5e8fa12..d723e36 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -9,6 +9,7 @@
return page_address(page);
return kmap_high(page);
}
+EXPORT_SYMBOL(kmap);
void kunmap(struct page *page)
{
@@ -18,6 +19,7 @@
return;
kunmap_high(page);
}
+EXPORT_SYMBOL(kunmap);
/*
* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
@@ -27,10 +29,10 @@
* However when holding an atomic kmap it is not legal to sleep, so atomic
* kmaps are appropriate for short, tight code paths only.
*/
-void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot(struct page *page, pgprot_t prot)
{
- enum fixed_addresses idx;
unsigned long vaddr;
+ int idx, type;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
pagefault_disable();
@@ -38,8 +40,7 @@
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);
BUG_ON(!pte_none(*(kmap_pte-idx)));
@@ -47,44 +48,56 @@
return (void *)vaddr;
}
+EXPORT_SYMBOL(kmap_atomic_prot);
-void *kmap_atomic(struct page *page, enum km_type type)
+void *__kmap_atomic(struct page *page)
{
- return kmap_atomic_prot(page, type, kmap_prot);
+ return kmap_atomic_prot(page, kmap_prot);
}
-
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
-{
- unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
- enum fixed_addresses 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. Keeping stale mappings around is a bad idea
- * also, in case the page changes cacheability attributes or becomes
- * a protected page in a hypervisor.
- */
- if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
- kpte_clear_flush(kmap_pte-idx, vaddr);
- else {
-#ifdef CONFIG_DEBUG_HIGHMEM
- BUG_ON(vaddr < PAGE_OFFSET);
- BUG_ON(vaddr >= (unsigned long)high_memory);
-#endif
- }
-
- pagefault_enable();
-}
+EXPORT_SYMBOL(__kmap_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)
{
- return kmap_atomic_prot_pfn(pfn, type, kmap_prot);
+ return kmap_atomic_prot_pfn(pfn, kmap_prot);
}
-EXPORT_SYMBOL_GPL(kmap_atomic_pfn); /* temporarily in use by i915 GEM until vmap */
+EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
+
+void __kunmap_atomic(void *kvaddr)
+{
+ unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+
+ if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+ vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+ int idx, type;
+
+ type = kmap_atomic_idx_pop();
+ idx = type + KM_TYPE_NR * smp_processor_id();
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+ WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+#endif
+ /*
+ * Force other mappings to Oops if they'll try to access this
+ * pte without first remap it. Keeping stale mappings around
+ * is a bad idea also, in case the page changes cacheability
+ * attributes or becomes a protected page in a hypervisor.
+ */
+ kpte_clear_flush(kmap_pte-idx, vaddr);
+ }
+#ifdef CONFIG_DEBUG_HIGHMEM
+ else {
+ BUG_ON(vaddr < PAGE_OFFSET);
+ BUG_ON(vaddr >= (unsigned long)high_memory);
+ }
+#endif
+
+ pagefault_enable();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
struct page *kmap_atomic_to_page(void *ptr)
{
@@ -98,12 +111,6 @@
pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
return pte_page(*pte);
}
-
-EXPORT_SYMBOL(kmap);
-EXPORT_SYMBOL(kunmap);
-EXPORT_SYMBOL(kmap_atomic);
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
-EXPORT_SYMBOL(kmap_atomic_prot);
EXPORT_SYMBOL(kmap_atomic_to_page);
void __init set_highmem_pages_init(void)