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/tile/mm/highmem.c b/arch/tile/mm/highmem.c
index 12ab137..8ef6595 100644
--- a/arch/tile/mm/highmem.c
+++ b/arch/tile/mm/highmem.c
@@ -56,50 +56,6 @@
}
EXPORT_SYMBOL(kunmap);
-static void debug_kmap_atomic_prot(enum km_type type)
-{
-#ifdef CONFIG_DEBUG_HIGHMEM
- static unsigned warn_count = 10;
-
- if (unlikely(warn_count == 0))
- return;
-
- if (unlikely(in_interrupt())) {
- if (in_irq()) {
- if (type != KM_IRQ0 && type != KM_IRQ1 &&
- type != KM_BIO_SRC_IRQ &&
- /* type != KM_BIO_DST_IRQ && */
- type != KM_BOUNCE_READ) {
- 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 */) {
- 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--;
- }
- }
-#endif
-}
-
/*
* Describe a single atomic mapping of a page on a given cpu at a
* given address, and allow it to be linked into a list.
@@ -240,10 +196,10 @@
* When holding an atomic kmap is 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;
pte_t *pte;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
@@ -255,8 +211,7 @@
if (!PageHighMem(page))
return page_address(page);
- debug_kmap_atomic_prot(type);
-
+ type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
pte = kmap_get_pte(vaddr);
@@ -269,25 +224,31 @@
}
EXPORT_SYMBOL(kmap_atomic_prot);
-void *kmap_atomic(struct page *page, enum km_type type)
+void *__kmap_atomic(struct page *page)
{
/* PAGE_NONE is a magic value that tells us to check immutability. */
return kmap_atomic_prot(page, type, PAGE_NONE);
}
-EXPORT_SYMBOL(kmap_atomic);
+EXPORT_SYMBOL(__kmap_atomic);
-void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
+void __kunmap_atomic(void *kvaddr)
{
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 try to access this pte without
- * first remapping it. Keeping stale mappings around is a bad idea.
- */
- if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) {
+ if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+ vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
pte_t *pte = kmap_get_pte(vaddr);
pte_t pteval = *pte;
+ int idx, type;
+
+ type = kmap_atomic_idx_pop();
+ idx = type + KM_TYPE_NR*smp_processor_id();
+
+ /*
+ * Force other mappings to Oops if they try to access this pte
+ * without first remapping it. Keeping stale mappings around
+ * is a bad idea.
+ */
BUG_ON(!pte_present(pteval) && !pte_migrating(pteval));
kmap_atomic_unregister(pte_page(pteval), vaddr);
kpte_clear_flush(pte, vaddr);
@@ -300,19 +261,19 @@
arch_flush_lazy_mmu_mode();
pagefault_enable();
}
-EXPORT_SYMBOL(kunmap_atomic_notypecheck);
+EXPORT_SYMBOL(__kunmap_atomic);
/*
* This API is supposed to allow us to map memory without a "struct page".
* Currently we don't support this, though this may change in the future.
*/
-void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+void *kmap_atomic_pfn(unsigned long pfn)
{
- return kmap_atomic(pfn_to_page(pfn), type);
+ return kmap_atomic(pfn_to_page(pfn));
}
-void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
+void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
{
- return kmap_atomic_prot(pfn_to_page(pfn), type, prot);
+ return kmap_atomic_prot(pfn_to_page(pfn), prot);
}
struct page *kmap_atomic_to_page(void *ptr)