shrinker: Kill old ->shrink API.

There are no more users of this API, so kill it dead, dead, dead and
quietly bury the corpse in a shallow, unmarked grave in a dark forest deep
in the hills...

[glommer@openvz.org: added flowers to the grave]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Greg Thelen <gthelen@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 799ebce..e364542 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -194,14 +194,6 @@
 }
 EXPORT_SYMBOL(unregister_shrinker);
 
-static inline int do_shrinker_shrink(struct shrinker *shrinker,
-				     struct shrink_control *sc,
-				     unsigned long nr_to_scan)
-{
-	sc->nr_to_scan = nr_to_scan;
-	return (*shrinker->shrink)(shrinker, sc);
-}
-
 #define SHRINK_BATCH 128
 
 static unsigned long
@@ -218,10 +210,7 @@
 	long batch_size = shrinker->batch ? shrinker->batch
 					  : SHRINK_BATCH;
 
-	if (shrinker->count_objects)
-		max_pass = shrinker->count_objects(shrinker, shrinkctl);
-	else
-		max_pass = do_shrinker_shrink(shrinker, shrinkctl, 0);
+	max_pass = shrinker->count_objects(shrinker, shrinkctl);
 	if (max_pass == 0)
 		return 0;
 
@@ -240,7 +229,7 @@
 	if (total_scan < 0) {
 		printk(KERN_ERR
 		"shrink_slab: %pF negative objects to delete nr=%ld\n",
-		       shrinker->shrink, total_scan);
+		       shrinker->scan_objects, total_scan);
 		total_scan = max_pass;
 	}
 
@@ -272,27 +261,13 @@
 				max_pass, delta, total_scan);
 
 	while (total_scan >= batch_size) {
+		unsigned long ret;
 
-		if (shrinker->scan_objects) {
-			unsigned long ret;
-			shrinkctl->nr_to_scan = batch_size;
-			ret = shrinker->scan_objects(shrinker, shrinkctl);
-
-			if (ret == SHRINK_STOP)
-				break;
-			freed += ret;
-		} else {
-			int nr_before;
-			long ret;
-
-			nr_before = do_shrinker_shrink(shrinker, shrinkctl, 0);
-			ret = do_shrinker_shrink(shrinker, shrinkctl,
-							batch_size);
-			if (ret == -1)
-				break;
-			if (ret < nr_before)
-				freed += nr_before - ret;
-		}
+		shrinkctl->nr_to_scan = batch_size;
+		ret = shrinker->scan_objects(shrinker, shrinkctl);
+		if (ret == SHRINK_STOP)
+			break;
+		freed += ret;
 
 		count_vm_events(SLABS_SCANNED, batch_size);
 		total_scan -= batch_size;