mm: bdi: export bdi_writeout_inc()

Fuse needs this for writable mmap support.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 13ab79d..0a24d55 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -135,6 +135,8 @@
 	return sum;
 }
 
+extern void bdi_writeout_inc(struct backing_dev_info *bdi);
+
 /*
  * maximal error of a stat counter.
  */
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index bbcb916..c90a1e8 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -168,6 +168,16 @@
 			      bdi->max_prop_frac);
 }
 
+void bdi_writeout_inc(struct backing_dev_info *bdi)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__bdi_writeout_inc(bdi);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(bdi_writeout_inc);
+
 static inline void task_dirty_inc(struct task_struct *tsk)
 {
 	prop_inc_single(&vm_dirties, &tsk->dirties);