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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/md/dm-path-selector.h
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/md/dm-path-selector.h')
-rw-r--r--kernel/drivers/md/dm-path-selector.h97
1 files changed, 97 insertions, 0 deletions
diff --git a/kernel/drivers/md/dm-path-selector.h b/kernel/drivers/md/dm-path-selector.h
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index 000000000..e7d1fa8b0
--- /dev/null
+++ b/kernel/drivers/md/dm-path-selector.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2003 Sistina Software.
+ * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ *
+ * Module Author: Heinz Mauelshagen
+ *
+ * This file is released under the GPL.
+ *
+ * Path-Selector registration.
+ */
+
+#ifndef DM_PATH_SELECTOR_H
+#define DM_PATH_SELECTOR_H
+
+#include <linux/device-mapper.h>
+
+#include "dm-mpath.h"
+
+/*
+ * We provide an abstraction for the code that chooses which path
+ * to send some io down.
+ */
+struct path_selector_type;
+struct path_selector {
+ struct path_selector_type *type;
+ void *context;
+};
+
+/* Information about a path selector type */
+struct path_selector_type {
+ char *name;
+ struct module *module;
+
+ unsigned int table_args;
+ unsigned int info_args;
+
+ /*
+ * Constructs a path selector object, takes custom arguments
+ */
+ int (*create) (struct path_selector *ps, unsigned argc, char **argv);
+ void (*destroy) (struct path_selector *ps);
+
+ /*
+ * Add an opaque path object, along with some selector specific
+ * path args (eg, path priority).
+ */
+ int (*add_path) (struct path_selector *ps, struct dm_path *path,
+ int argc, char **argv, char **error);
+
+ /*
+ * Chooses a path for this io, if no paths are available then
+ * NULL will be returned.
+ *
+ * repeat_count is the number of times to use the path before
+ * calling the function again. 0 means don't call it again unless
+ * the path fails.
+ */
+ struct dm_path *(*select_path) (struct path_selector *ps,
+ unsigned *repeat_count,
+ size_t nr_bytes);
+
+ /*
+ * Notify the selector that a path has failed.
+ */
+ void (*fail_path) (struct path_selector *ps, struct dm_path *p);
+
+ /*
+ * Ask selector to reinstate a path.
+ */
+ int (*reinstate_path) (struct path_selector *ps, struct dm_path *p);
+
+ /*
+ * Table content based on parameters added in ps_add_path_fn
+ * or path selector status
+ */
+ int (*status) (struct path_selector *ps, struct dm_path *path,
+ status_type_t type, char *result, unsigned int maxlen);
+
+ int (*start_io) (struct path_selector *ps, struct dm_path *path,
+ size_t nr_bytes);
+ int (*end_io) (struct path_selector *ps, struct dm_path *path,
+ size_t nr_bytes);
+};
+
+/* Register a path selector */
+int dm_register_path_selector(struct path_selector_type *type);
+
+/* Unregister a path selector */
+int dm_unregister_path_selector(struct path_selector_type *type);
+
+/* Returns a registered path selector type */
+struct path_selector_type *dm_get_path_selector(const char *name);
+
+/* Releases a path selector */
+void dm_put_path_selector(struct path_selector_type *pst);
+
+#endif