mm: use vm_unmapped_area() on parisc architecture

Update the parisc arch_get_unmapped_area function to make use of
vm_unmapped_area() instead of implementing a brute force search.

[akpm@linux-foundation.org: remove now-unused DCACHE_ALIGN(), per James]
Signed-off-by: NMichel Lespinasse <walken@google.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Acked-by: NHelge Deller <deller@gmx.de>
Tested-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/parisc/kernel/sys_parisc.c

@@ -35,22 +35,17 @@
 
 static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
 {
-	struct vm_area_struct *vma;
+	struct vm_unmapped_area_info info;
 
-	addr = PAGE_ALIGN(addr);
-
-	for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
-		/* At this point:  (!vma || addr < vma->vm_end). */
-		if (TASK_SIZE - len < addr)
-			return -ENOMEM;
-		if (!vma || addr + len <= vma->vm_start)
-			return addr;
-		addr = vma->vm_end;
-	}
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = PAGE_ALIGN(addr);
+	info.high_limit = TASK_SIZE;
+	info.align_mask = 0;
+	info.align_offset = 0;
+	return vm_unmapped_area(&info);
 }
 
-#define DCACHE_ALIGN(addr) (((addr) + (SHMLBA - 1)) &~ (SHMLBA - 1))
-
 /*
  * We need to know the offset to use.  Old scheme was to look for
  * existing mapping and use the same offset.  New scheme is to use the
@@ -63,30 +58,21 @@ static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
  */
 static int get_offset(struct address_space *mapping)
 {
-	int offset = (unsigned long) mapping << (PAGE_SHIFT - 8);
-	return offset & 0x3FF000;
+	return (unsigned long) mapping >> 8;
 }
 
 static unsigned long get_shared_area(struct address_space *mapping,
 		unsigned long addr, unsigned long len, unsigned long pgoff)
 {
-	struct vm_area_struct *vma;
-	int offset = mapping ? get_offset(mapping) : 0;
+	struct vm_unmapped_area_info info;
 
-	offset = (offset + (pgoff << PAGE_SHIFT)) & 0x3FF000;
-
-	addr = DCACHE_ALIGN(addr - offset) + offset;
-
-	for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
-		/* At this point:  (!vma || addr < vma->vm_end). */
-		if (TASK_SIZE - len < addr)
-			return -ENOMEM;
-		if (!vma || addr + len <= vma->vm_start)
-			return addr;
-		addr = DCACHE_ALIGN(vma->vm_end - offset) + offset;
-		if (addr < vma->vm_end) /* handle wraparound */
-			return -ENOMEM;
-	}
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = PAGE_ALIGN(addr);
+	info.high_limit = TASK_SIZE;
+	info.align_mask = PAGE_MASK & (SHMLBA - 1);
+	info.align_offset = (get_offset(mapping) + pgoff) << PAGE_SHIFT;
+	return vm_unmapped_area(&info);
 }
 
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,