mm: remove sysctl_extfrag_handler()

sysctl_extfrag_handler() neglects to propagate the return value from
proc_dointvec_minmax() to its caller.  It's a wrapper that doesn't need
to exist, so just use proc_dointvec_minmax() directly.

Link: http://lkml.kernel.org/r/20190104032557.3056-1-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Aditya Pakki <pakki001@umn.edu>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/compaction.h

@@ -88,8 +88,6 @@ extern int sysctl_compact_memory;
 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
 			void __user *buffer, size_t *length, loff_t *ppos);
 extern int sysctl_extfrag_threshold;
-extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
-			void __user *buffer, size_t *length, loff_t *ppos);
 extern int sysctl_compact_unevictable_allowed;
 
 extern int fragmentation_index(struct zone *zone, unsigned int order);

kernel/sysctl.c

@@ -1460,7 +1460,7 @@ static struct ctl_table vm_table[] = {
 		.data		= &sysctl_extfrag_threshold,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= sysctl_extfrag_handler,
+		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &min_extfrag_threshold,
 		.extra2		= &max_extfrag_threshold,
 	},

mm/compaction.c

@@ -1876,14 +1876,6 @@ int sysctl_compaction_handler(struct ctl_table *table, int write,
 	return 0;
 }
 
-int sysctl_extfrag_handler(struct ctl_table *table, int write,
-			void __user *buffer, size_t *length, loff_t *ppos)
-{
-	proc_dointvec_minmax(table, write, buffer, length, ppos);
-
-	return 0;
-}
-
 #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
 static ssize_t sysfs_compact_node(struct device *dev,
 			struct device_attribute *attr,