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/frv/mm/highmem.c b/arch/frv/mm/highmem.c
index eadd076..61088dc 100644
--- a/arch/frv/mm/highmem.c
+++ b/arch/frv/mm/highmem.c
@@ -36,3 +36,53 @@
{
return virt_to_page(ptr);
}
+
+void *__kmap_atomic(struct page *page)
+{
+ unsigned long paddr;
+ int type;
+
+ pagefault_disable();
+ type = kmap_atomic_idx_push();
+ paddr = page_to_phys(page);
+
+ switch (type) {
+ /*
+ * The first 4 primary maps are reserved for architecture code
+ */
+ case 0: return __kmap_atomic_primary(4, paddr, 6);
+ case 1: return __kmap_atomic_primary(5, paddr, 7);
+ case 2: return __kmap_atomic_primary(6, paddr, 8);
+ case 3: return __kmap_atomic_primary(7, paddr, 9);
+ case 4: return __kmap_atomic_primary(8, paddr, 10);
+
+ case 5 ... 5 + NR_TLB_LINES - 1:
+ return __kmap_atomic_secondary(type - 5, paddr);
+
+ default:
+ BUG();
+ return NULL;
+ }
+}
+EXPORT_SYMBOL(__kmap_atomic);
+
+void __kunmap_atomic(void *kvaddr)
+{
+ int type = kmap_atomic_idx_pop();
+ switch (type) {
+ case 0: __kunmap_atomic_primary(4, 6); break;
+ case 1: __kunmap_atomic_primary(5, 7); break;
+ case 2: __kunmap_atomic_primary(6, 8); break;
+ case 3: __kunmap_atomic_primary(7, 9); break;
+ case 4: __kunmap_atomic_primary(8, 10); break;
+
+ case 5 ... 5 + NR_TLB_LINES - 1:
+ __kunmap_atomic_secondary(type - 5, kvaddr);
+ break;
+
+ default:
+ BUG();
+ }
+ pagefault_enable();
+}
+EXPORT_SYMBOL(__kunmap_atomic);