[POWERPC] unmap_vm_area becomes unmap_kernel_range for the public

This makes unmap_vm_area static and a wrapper around a new
exported unmap_kernel_range that takes an explicit range instead
of a vm_area struct.

This makes it more versatile for code that wants to play with kernel
page tables outside of the standard vmalloc area.

(One example is some rework of the PowerPC PCI IO space mapping
code that depends on that patch and removes some code duplication
and horrible abuse of forged struct vm_struct).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 9 insertions, 4 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d3a9c53..ddf8714 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -68,12 +68,12 @@ static inline void vunmap_pud_range(pgd_t *pgd, unsigned long addr,
 	} while (pud++, addr = next, addr != end);
 }
 
-void unmap_vm_area(struct vm_struct *area)
+void unmap_kernel_range(unsigned long addr, unsigned long size)
 {
 	pgd_t *pgd;
 	unsigned long next;
-	unsigned long addr = (unsigned long) area->addr;
-	unsigned long end = addr + area->size;
+	unsigned long start = addr;
+	unsigned long end = addr + size;
 
 	BUG_ON(addr >= end);
 	pgd = pgd_offset_k(addr);
@@ -84,7 +84,12 @@ void unmap_vm_area(struct vm_struct *area)
 			continue;
 		vunmap_pud_range(pgd, addr, next);
 	} while (pgd++, addr = next, addr != end);
-	flush_tlb_kernel_range((unsigned long) area->addr, end);
+	flush_tlb_kernel_range(start, end);
+}
+
+static void unmap_vm_area(struct vm_struct *area)
+{
+	unmap_kernel_range((unsigned long)area->addr, area->size);
 }
 
 static int vmap_pte_range(pmd_t *pmd, unsigned long addr,