Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/md/dm-round-robin.c b/drivers/md/dm-round-robin.c
new file mode 100644
index 0000000..d002486
--- /dev/null
+++ b/drivers/md/dm-round-robin.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2003 Sistina Software.
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
+ *
+ * Module Author: Heinz Mauelshagen
+ *
+ * This file is released under the GPL.
+ *
+ * Round-robin path selector.
+ */
+
+#include "dm.h"
+#include "dm-path-selector.h"
+
+#include <linux/slab.h>
+
+/*-----------------------------------------------------------------
+ * Path-handling code, paths are held in lists
+ *---------------------------------------------------------------*/
+struct path_info {
+ struct list_head list;
+ struct path *path;
+ unsigned repeat_count;
+};
+
+static void free_paths(struct list_head *paths)
+{
+ struct path_info *pi, *next;
+
+ list_for_each_entry_safe(pi, next, paths, list) {
+ list_del(&pi->list);
+ kfree(pi);
+ }
+}
+
+/*-----------------------------------------------------------------
+ * Round-robin selector
+ *---------------------------------------------------------------*/
+
+#define RR_MIN_IO 1000
+
+struct selector {
+ struct list_head valid_paths;
+ struct list_head invalid_paths;
+};
+
+static struct selector *alloc_selector(void)
+{
+ struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);
+
+ if (s) {
+ INIT_LIST_HEAD(&s->valid_paths);
+ INIT_LIST_HEAD(&s->invalid_paths);
+ }
+
+ return s;
+}
+
+static int rr_create(struct path_selector *ps, unsigned argc, char **argv)
+{
+ struct selector *s;
+
+ s = alloc_selector();
+ if (!s)
+ return -ENOMEM;
+
+ ps->context = s;
+ return 0;
+}
+
+static void rr_destroy(struct path_selector *ps)
+{
+ struct selector *s = (struct selector *) ps->context;
+
+ free_paths(&s->valid_paths);
+ free_paths(&s->invalid_paths);
+ kfree(s);
+ ps->context = NULL;
+}
+
+static int rr_status(struct path_selector *ps, struct path *path,
+ status_type_t type, char *result, unsigned int maxlen)
+{
+ struct path_info *pi;
+ int sz = 0;
+
+ if (!path)
+ DMEMIT("0 ");
+ else {
+ switch(type) {
+ case STATUSTYPE_INFO:
+ break;
+ case STATUSTYPE_TABLE:
+ pi = path->pscontext;
+ DMEMIT("%u ", pi->repeat_count);
+ break;
+ }
+ }
+
+ return sz;
+}
+
+/*
+ * Called during initialisation to register each path with an
+ * optional repeat_count.
+ */
+static int rr_add_path(struct path_selector *ps, struct path *path,
+ int argc, char **argv, char **error)
+{
+ struct selector *s = (struct selector *) ps->context;
+ struct path_info *pi;
+ unsigned repeat_count = RR_MIN_IO;
+
+ if (argc > 1) {
+ *error = "round-robin ps: incorrect number of arguments";
+ return -EINVAL;
+ }
+
+ /* First path argument is number of I/Os before switching path */
+ if ((argc == 1) && (sscanf(argv[0], "%u", &repeat_count) != 1)) {
+ *error = "round-robin ps: invalid repeat count";
+ return -EINVAL;
+ }
+
+ /* allocate the path */
+ pi = kmalloc(sizeof(*pi), GFP_KERNEL);
+ if (!pi) {
+ *error = "round-robin ps: Error allocating path context";
+ return -ENOMEM;
+ }
+
+ pi->path = path;
+ pi->repeat_count = repeat_count;
+
+ path->pscontext = pi;
+
+ list_add(&pi->list, &s->valid_paths);
+
+ return 0;
+}
+
+static void rr_fail_path(struct path_selector *ps, struct path *p)
+{
+ struct selector *s = (struct selector *) ps->context;
+ struct path_info *pi = p->pscontext;
+
+ list_move(&pi->list, &s->invalid_paths);
+}
+
+static int rr_reinstate_path(struct path_selector *ps, struct path *p)
+{
+ struct selector *s = (struct selector *) ps->context;
+ struct path_info *pi = p->pscontext;
+
+ list_move(&pi->list, &s->valid_paths);
+
+ return 0;
+}
+
+static struct path *rr_select_path(struct path_selector *ps,
+ unsigned *repeat_count)
+{
+ struct selector *s = (struct selector *) ps->context;
+ struct path_info *pi = NULL;
+
+ if (!list_empty(&s->valid_paths)) {
+ pi = list_entry(s->valid_paths.next, struct path_info, list);
+ list_move_tail(&pi->list, &s->valid_paths);
+ *repeat_count = pi->repeat_count;
+ }
+
+ return pi ? pi->path : NULL;
+}
+
+static struct path_selector_type rr_ps = {
+ .name = "round-robin",
+ .module = THIS_MODULE,
+ .table_args = 1,
+ .info_args = 0,
+ .create = rr_create,
+ .destroy = rr_destroy,
+ .status = rr_status,
+ .add_path = rr_add_path,
+ .fail_path = rr_fail_path,
+ .reinstate_path = rr_reinstate_path,
+ .select_path = rr_select_path,
+};
+
+static int __init dm_rr_init(void)
+{
+ int r = dm_register_path_selector(&rr_ps);
+
+ if (r < 0)
+ DMERR("round-robin: register failed %d", r);
+
+ DMINFO("dm-round-robin version 1.0.0 loaded");
+
+ return r;
+}
+
+static void __exit dm_rr_exit(void)
+{
+ int r = dm_unregister_path_selector(&rr_ps);
+
+ if (r < 0)
+ DMERR("round-robin: unregister failed %d", r);
+}
+
+module_init(dm_rr_init);
+module_exit(dm_rr_exit);
+
+MODULE_DESCRIPTION(DM_NAME " round-robin multipath path selector");
+MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");
