3  * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
9  * Round-robin path selector.
12 #include <linux/device-mapper.h>
14 #include "dm-path-selector.h"
19 #define DM_MSG_PREFIX "multipath round-robin"
23 /*-----------------------------------------------------------------
24  * Path-handling code, paths are held in lists
25  *---------------------------------------------------------------*/
37 		list_del(&pi->list);  in free_paths()
42 /*-----------------------------------------------------------------
43  * Round-robin selector
44  *---------------------------------------------------------------*/
57 		INIT_LIST_HEAD(&s->valid_paths);  in alloc_selector()
58 		INIT_LIST_HEAD(&s->invalid_paths);  in alloc_selector()
59 		spin_lock_init(&s->lock);  in alloc_selector()
71 		return -ENOMEM;  in rr_create()
73 	ps->context = s;  in rr_create()
79 	struct selector *s = ps->context;  in rr_destroy()
81 	free_paths(&s->valid_paths);  in rr_destroy()
82 	free_paths(&s->invalid_paths);  in rr_destroy()
84 	ps->context = NULL;  in rr_destroy()
100 			pi = path->pscontext;  in rr_status()
101 			DMEMIT("%u ", pi->repeat_count);  in rr_status()
116 	struct selector *s = ps->context;  in rr_add_path()
123 		*error = "round-robin ps: incorrect number of arguments";  in rr_add_path()
124 		return -EINVAL;  in rr_add_path()
129 		*error = "round-robin ps: invalid repeat count";  in rr_add_path()
130 		return -EINVAL;  in rr_add_path()
141 		*error = "round-robin ps: Error allocating path context";  in rr_add_path()
142 		return -ENOMEM;  in rr_add_path()
145 	pi->path = path;  in rr_add_path()
146 	pi->repeat_count = repeat_count;  in rr_add_path()
148 	path->pscontext = pi;  in rr_add_path()
150 	spin_lock_irqsave(&s->lock, flags);  in rr_add_path()
151 	list_add_tail(&pi->list, &s->valid_paths);  in rr_add_path()
152 	spin_unlock_irqrestore(&s->lock, flags);  in rr_add_path()
160 	struct selector *s = ps->context;  in rr_fail_path()
161 	struct path_info *pi = p->pscontext;  in rr_fail_path()
163 	spin_lock_irqsave(&s->lock, flags);  in rr_fail_path()
164 	list_move(&pi->list, &s->invalid_paths);  in rr_fail_path()
165 	spin_unlock_irqrestore(&s->lock, flags);  in rr_fail_path()
171 	struct selector *s = ps->context;  in rr_reinstate_path()
172 	struct path_info *pi = p->pscontext;  in rr_reinstate_path()
174 	spin_lock_irqsave(&s->lock, flags);  in rr_reinstate_path()
175 	list_move(&pi->list, &s->valid_paths);  in rr_reinstate_path()
176 	spin_unlock_irqrestore(&s->lock, flags);  in rr_reinstate_path()
184 	struct selector *s = ps->context;  in rr_select_path()
187 	spin_lock_irqsave(&s->lock, flags);  in rr_select_path()
188 	if (!list_empty(&s->valid_paths)) {  in rr_select_path()
189 		pi = list_entry(s->valid_paths.next, struct path_info, list);  in rr_select_path()
190 		list_move_tail(&pi->list, &s->valid_paths);  in rr_select_path()
192 	spin_unlock_irqrestore(&s->lock, flags);  in rr_select_path()
194 	return pi ? pi->path : NULL;  in rr_select_path()
198 	.name = "round-robin",
234 MODULE_DESCRIPTION(DM_NAME " round-robin multipath path selector");
235 MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");