+/*
+ * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ * Copyright (C) 2007 The Regents of the University of California.
+ * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ * Written by Brian Behlendorf <behlendorf1@llnl.gov>.
+ * UCRL-CODE-235197
+ *
+ * This file is part of the SPL, Solaris Porting Layer.
+ *
+ * The SPL is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * The SPL is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with the SPL. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Solaris Porting Layer (SPL) Shrinker Implementation.
+ */
+
+#include <sys/kmem.h>
+#include <sys/shrinker.h>
+
+#ifdef HAVE_SINGLE_SHRINKER_CALLBACK
+/* 3.0-3.11: single shrink() callback, which we wrap to carry both functions */
+struct spl_shrinker_wrap {
+ struct shrinker shrinker;
+ spl_shrinker_cb countfunc;
+ spl_shrinker_cb scanfunc;
+};
+
+static int
+spl_shrinker_single_cb(struct shrinker *shrinker, struct shrink_control *sc)
+{
+ struct spl_shrinker_wrap *sw = (struct spl_shrinker_wrap *)shrinker;
+
+ if (sc->nr_to_scan != 0)
+ (void) sw->scanfunc(&sw->shrinker, sc);
+ return (sw->countfunc(&sw->shrinker, sc));
+}
+#endif
+
+struct shrinker *
+spl_register_shrinker(const char *name, spl_shrinker_cb countfunc,
+ spl_shrinker_cb scanfunc, int seek_cost)
+{
+ struct shrinker *shrinker;
+
+ /* allocate shrinker */
+#if defined(HAVE_SHRINKER_REGISTER)
+ /* 6.7: kernel will allocate the shrinker for us */
+ shrinker = shrinker_alloc(0, name);
+#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
+ /* 3.12-6.6: we allocate the shrinker */
+ shrinker = kmem_zalloc(sizeof (struct shrinker), KM_SLEEP);
+#elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
+ /* 3.0-3.11: allocate a wrapper */
+ struct spl_shrinker_wrap *sw =
+ kmem_zalloc(sizeof (struct spl_shrinker_wrap), KM_SLEEP);
+ shrinker = &sw->shrinker;
+#else
+ /* 2.x-2.6.22, or a newer shrinker API has been introduced. */
+#error "Unknown shrinker API"
+#endif
+
+ if (shrinker == NULL)
+ return (NULL);
+
+ /* set callbacks */
+#ifdef HAVE_SINGLE_SHRINKER_CALLBACK
+ sw->countfunc = countfunc;
+ sw->scanfunc = scanfunc;
+ shrinker->shrink = spl_shrinker_single_cb;
+#else
+ shrinker->count_objects = countfunc;
+ shrinker->scan_objects = scanfunc;
+#endif
+
+ /* set params */
+ shrinker->seeks = seek_cost;
+
+ /* register with kernel */
+#if defined(HAVE_SHRINKER_REGISTER)
+ shrinker_register(shrinker);
+#elif defined(HAVE_REGISTER_SHRINKER_VARARG)
+ register_shrinker(shrinker, name);
+#else
+ register_shrinker(shrinker);
+#endif
+
+ return (shrinker);
+}
+EXPORT_SYMBOL(spl_register_shrinker);
+
+void
+spl_unregister_shrinker(struct shrinker *shrinker)
+{
+#if defined(HAVE_SHRINKER_REGISTER)
+ shrinker_free(shrinker);
+#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
+ unregister_shrinker(shrinker);
+ kmem_free(shrinker, sizeof (struct shrinker));
+#elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
+ unregister_shrinker(shrinker);
+ kmem_free(shrinker, sizeof (struct spl_shrinker_wrap));
+#else
+#error "Unknown shrinker API"
+#endif
+}
+EXPORT_SYMBOL(spl_unregister_shrinker);