sysctl: add proc_do_large_bitmap

The new function can be used to read/write large bitmaps via /proc. A
comma separated range format is used for compact output and input
(e.g. 1,3-4,10-10).

Writing into the file will first reset the bitmap then update it
based on the given input.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index f66014c..7bb5cb6 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -980,6 +980,8 @@
 				  void __user *, size_t *, loff_t *);
 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
 				      void __user *, size_t *, loff_t *);
+extern int proc_do_large_bitmap(struct ctl_table *, int,
+				void __user *, size_t *, loff_t *);
 
 /*
  * Register a set of sysctl names by calling register_sysctl_table