[PATCH] NOMMU: Supply get_unmapped_area() to fix NOMMU SYSV SHM

[David Howells <dhowells@redhat.com>]

From: David Howells <dhowells@redhat.com>

Supply a get_unmapped_area() to fix NOMMU SYSV SHM support.

Signed-Off-By: David Howells <dhowells@redhat.com>
---

 mm/nommu.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index 23fb033..ba6df4d 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1193,6 +1193,28 @@ void unmap_mapping_range(struct address_space *mapping,
 EXPORT_SYMBOL(unmap_mapping_range);
 
 /*
+ * ask for an unmapped area at which to create a mapping on a file
+ */
+unsigned long get_unmapped_area(struct file *file, unsigned long addr,
+				unsigned long len, unsigned long pgoff,
+				unsigned long flags)
+{
+	unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
+				  unsigned long, unsigned long);
+
+	get_area = current->mm->get_unmapped_area;
+	if (file && file->f_op && file->f_op->get_unmapped_area)
+		get_area = file->f_op->get_unmapped_area;
+
+	if (!get_area)
+		return -ENOSYS;
+
+	return get_area(file, addr, len, pgoff, flags);
+}
+
+EXPORT_SYMBOL(get_unmapped_area);
+
+/*
  * Check that a process has enough memory to allocate a new virtual
  * mapping. 0 means there is enough memory for the allocation to
  * succeed and -ENOMEM implies there is not.