mm: bdi: export bdi_writeout_inc()

Fuse needs this for writable mmap support.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/backing-dev.h

@@ -135,6 +135,8 @@ static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
 	return sum;
 }
 
+extern void bdi_writeout_inc(struct backing_dev_info *bdi);
+
 /*
  * maximal error of a stat counter.
  */

mm/page-writeback.c

@@ -168,6 +168,16 @@ static inline void __bdi_writeout_inc(struct backing_dev_info *bdi)
 			      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);