-/*****************************************************************************\
+/*
* 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).
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
- * For details, see <http://github.com/behlendorf/spl/>.
+ * 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
*
* 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_MM_COMPAT_H
-#define _SPL_MM_COMPAT_H
+#define _SPL_MM_COMPAT_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 */
+
/*
- * Linux 2.6.31 API Change.
- * Individual pages_{min,low,high} moved in to watermark array.
+ * 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);
*/
-#ifndef min_wmark_pages
-#define min_wmark_pages(z) (z->pages_min)
-#endif
-#ifndef low_wmark_pages
-#define low_wmark_pages(z) (z->pages_low)
-#endif
+#define spl_register_shrinker(x) register_shrinker(x)
+#define spl_unregister_shrinker(x) unregister_shrinker(x)
-#ifndef high_wmark_pages
-#define high_wmark_pages(z) (z->pages_high)
-#endif
+/*
+ * 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)); \
+}
/*
- * 2.6.37 API compat,
- * The function invalidate_inodes() is no longer exported by the kernel.
- * The prototype however is still available which means it is safe
- * to acquire the symbol's address using spl_kallsyms_lookup_name().
+ * Linux 3.0 to 3.11 Shrinker API Compatibility.
*/
-#ifndef HAVE_INVALIDATE_INODES
-typedef int (*invalidate_inodes_t)(struct super_block *sb);
-extern invalidate_inodes_t invalidate_inodes_fn;
-#define invalidate_inodes(sb) invalidate_inodes_fn(sb)
-#endif /* HAVE_INVALIDATE_INODES */
+#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_MM_COMPAT_H */
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