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authorJonathan Brassow <jbrassow@redhat.com>2008-02-08 02:11:19 +0000
committerAlasdair G Kergon <agk@redhat.com>2008-02-08 02:11:19 +0000
commitfb8b284806124bef250196007d7373ea3fe26194 (patch)
tree8e34cc38a2c5a0e8e7a937c53421cf7f76466a00 /drivers/md/dm-log.c
parent304f3f6a58301316da612d7bf21d9abe1369d456 (diff)
downloadlwn-fb8b284806124bef250196007d7373ea3fe26194.tar.gz
lwn-fb8b284806124bef250196007d7373ea3fe26194.zip
dm log: auto load modules
If the log type is not recognised, attempt to load the module 'dm-log-<type>.ko'. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-log.c')
-rw-r--r--drivers/md/dm-log.c51
1 files changed, 50 insertions, 1 deletions
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 072ee4353eab..2a74b2142f50 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -41,7 +41,7 @@ int dm_unregister_dirty_log_type(struct dirty_log_type *type)
return 0;
}
-static struct dirty_log_type *get_type(const char *type_name)
+static struct dirty_log_type *_get_type(const char *type_name)
{
struct dirty_log_type *type;
@@ -61,6 +61,55 @@ static struct dirty_log_type *get_type(const char *type_name)
return NULL;
}
+/*
+ * get_type
+ * @type_name
+ *
+ * Attempt to retrieve the dirty_log_type by name. If not already
+ * available, attempt to load the appropriate module.
+ *
+ * Log modules are named "dm-log-" followed by the 'type_name'.
+ * Modules may contain multiple types.
+ * This function will first try the module "dm-log-<type_name>",
+ * then truncate 'type_name' on the last '-' and try again.
+ *
+ * For example, if type_name was "clustered-disk", it would search
+ * 'dm-log-clustered-disk' then 'dm-log-clustered'.
+ *
+ * Returns: dirty_log_type* on success, NULL on failure
+ */
+static struct dirty_log_type *get_type(const char *type_name)
+{
+ char *p, *type_name_dup;
+ struct dirty_log_type *type;
+
+ type = _get_type(type_name);
+ if (type)
+ return type;
+
+ type_name_dup = kstrdup(type_name, GFP_KERNEL);
+ if (!type_name_dup) {
+ DMWARN("No memory left to attempt log module load for \"%s\"",
+ type_name);
+ return NULL;
+ }
+
+ while (request_module("dm-log-%s", type_name_dup) ||
+ !(type = _get_type(type_name))) {
+ p = strrchr(type_name_dup, '-');
+ if (!p)
+ break;
+ p[0] = '\0';
+ }
+
+ if (!type)
+ DMWARN("Module for logging type \"%s\" not found.", type_name);
+
+ kfree(type_name_dup);
+
+ return type;
+}
+
static void put_type(struct dirty_log_type *type)
{
spin_lock(&_lock);