Merge branch 'zfsonlinux/merge-spl'

Merge a minimal version of the zfsonlinux/spl repository in to the
zfsonlinux/zfs repository.  Care was taken to prevent file conflicts
when merging and to preserve the spl repository history.  The spl
kernel module remains under the GPLv2 license as documented by the
additional THIRDPARTYLICENSE.gplv2 file.

Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 209 insertions, 0 deletions

diff --git a/include/spl/sys/shrinker.h b/include/spl/sys/shrinker.h
new file mode 100644
index 000000000..28c1fa78c
--- /dev/null
+++ b/include/spl/sys/shrinker.h
@@ -0,0 +1,209 @@
+/*
+ *  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 <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  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/>.
+ */
+
+#ifndef _SPL_SHRINKER_H
+#define	_SPL_SHRINKER_H
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+
+#if !defined(HAVE_SHRINK_CONTROL_STRUCT)
+struct shrink_control {
+	gfp_t gfp_mask;
+	unsigned long nr_to_scan;
+};
+#endif /* HAVE_SHRINK_CONTROL_STRUCT */
+
+/*
+ * Due to frequent changes in the shrinker API the following
+ * compatibility wrappers should be used.  They are as follows:
+ *
+ * SPL_SHRINKER_DECLARE is used to declare the shrinker which is
+ * passed to spl_register_shrinker()/spl_unregister_shrinker().  Use
+ * shrinker_name to set the shrinker variable name, shrinker_callback
+ * to set the callback function, and seek_cost to define the cost of
+ * reclaiming an object.
+ *
+ *   SPL_SHRINKER_DECLARE(shrinker_name, shrinker_callback, seek_cost);
+ *
+ * SPL_SHRINKER_CALLBACK_FWD_DECLARE is used when a forward declaration
+ * of the shrinker callback function is required.  Only the callback
+ * function needs to be passed.
+ *
+ *   SPL_SHRINKER_CALLBACK_FWD_DECLARE(shrinker_callback);
+ *
+ * SPL_SHRINKER_CALLBACK_WRAPPER is used to declare the callback function
+ * which is registered with the shrinker.  This function will call your
+ * custom shrinker which must use the following prototype.  Notice the
+ * leading __'s, these must be appended to the callback_function name.
+ *
+ *   int  __shrinker_callback(struct shrinker *, struct shrink_control *)
+ *   SPL_SHRINKER_CALLBACK_WRAPPER(shrinker_callback);a
+ *
+ *
+ * Example:
+ *
+ * SPL_SHRINKER_CALLBACK_FWD_DECLARE(my_shrinker_fn);
+ * SPL_SHRINKER_DECLARE(my_shrinker, my_shrinker_fn, 1);
+ *
+ * static int
+ * __my_shrinker_fn(struct shrinker *shrink, struct shrink_control *sc)
+ * {
+ *	if (sc->nr_to_scan) {
+ *		...scan objects in the cache and reclaim them...
+ *	}
+ *
+ *	...calculate number of objects in the cache...
+ *
+ *	return (number of objects in the cache);
+ * }
+ * SPL_SHRINKER_CALLBACK_WRAPPER(my_shrinker_fn);
+ */
+
+#define	spl_register_shrinker(x)	register_shrinker(x)
+#define	spl_unregister_shrinker(x)	unregister_shrinker(x)
+
+/*
+ * Linux 2.6.23 - 2.6.34 Shrinker API Compatibility.
+ */
+#if defined(HAVE_2ARGS_OLD_SHRINKER_CALLBACK)
+#define	SPL_SHRINKER_DECLARE(s, x, y)					\
+static struct shrinker s = {						\
+	.shrink = x,							\
+	.seeks = y							\
+}
+
+#define	SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn)				\
+static int fn(int nr_to_scan, unsigned int gfp_mask)
+
+#define	SPL_SHRINKER_CALLBACK_WRAPPER(fn)				\
+static int								\
+fn(int nr_to_scan, unsigned int gfp_mask)				\
+{									\
+	struct shrink_control sc;					\
+									\
+	sc.nr_to_scan = nr_to_scan;					\
+	sc.gfp_mask = gfp_mask;						\
+									\
+	return (__ ## fn(NULL, &sc));					\
+}
+
+/*
+ * Linux 2.6.35 to 2.6.39 Shrinker API Compatibility.
+ */
+#elif defined(HAVE_3ARGS_SHRINKER_CALLBACK)
+#define	SPL_SHRINKER_DECLARE(s, x, y)					\
+static struct shrinker s = {						\
+	.shrink = x,							\
+	.seeks = y							\
+}
+
+#define	SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn)				\
+static int fn(struct shrinker *, int, unsigned int)
+
+#define	SPL_SHRINKER_CALLBACK_WRAPPER(fn)				\
+static int								\
+fn(struct shrinker *shrink, int nr_to_scan, unsigned int gfp_mask)	\
+{									\
+	struct shrink_control sc;					\
+									\
+	sc.nr_to_scan = nr_to_scan;					\
+	sc.gfp_mask = gfp_mask;						\
+									\
+	return (__ ## fn(shrink, &sc));					\
+}
+
+/*
+ * Linux 3.0 to 3.11 Shrinker API Compatibility.
+ */
+#elif defined(HAVE_2ARGS_NEW_SHRINKER_CALLBACK)
+#define	SPL_SHRINKER_DECLARE(s, x, y)					\
+static struct shrinker s = {						\
+	.shrink = x,							\
+	.seeks = y							\
+}
+
+#define	SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn)				\
+static int fn(struct shrinker *, struct shrink_control *)
+
+#define	SPL_SHRINKER_CALLBACK_WRAPPER(fn)				\
+static int								\
+fn(struct shrinker *shrink, struct shrink_control *sc)			\
+{									\
+	return (__ ## fn(shrink, sc));					\
+}
+
+/*
+ * Linux 3.12 and later Shrinker API Compatibility.
+ */
+#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
+#define	SPL_SHRINKER_DECLARE(s, x, y)					\
+static struct shrinker s = {						\
+	.count_objects = x ## _count_objects,				\
+	.scan_objects = x ## _scan_objects,				\
+	.seeks = y							\
+}
+
+#define	SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn)				\
+static unsigned long fn ## _count_objects(struct shrinker *,		\
+    struct shrink_control *);						\
+static unsigned long fn ## _scan_objects(struct shrinker *,		\
+    struct shrink_control *)
+
+#define	SPL_SHRINKER_CALLBACK_WRAPPER(fn)				\
+static unsigned long							\
+fn ## _count_objects(struct shrinker *shrink, struct shrink_control *sc)\
+{									\
+	int __ret__;							\
+									\
+	sc->nr_to_scan = 0;						\
+	__ret__ = __ ## fn(NULL, sc);					\
+									\
+	/* Errors may not be returned and must be converted to zeros */	\
+	return ((__ret__ < 0) ? 0 : __ret__);				\
+}									\
+									\
+static unsigned long							\
+fn ## _scan_objects(struct shrinker *shrink, struct shrink_control *sc)	\
+{									\
+	int __ret__;							\
+									\
+	__ret__ = __ ## fn(NULL, sc);					\
+	return ((__ret__ < 0) ? SHRINK_STOP : __ret__);			\
+}
+#else
+/*
+ * Linux 2.x to 2.6.22, or a newer shrinker API has been introduced.
+ */
+#error "Unknown shrinker callback"
+#endif
+
+#if defined(HAVE_SPLIT_SHRINKER_CALLBACK)
+typedef unsigned long	spl_shrinker_t;
+#else
+typedef int		spl_shrinker_t;
+#define	SHRINK_STOP	(-1)
+#endif
+
+#endif /* SPL_SHRINKER_H */