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path: root/drivers/md/dm-mpath.c
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Diffstat (limited to 'drivers/md/dm-mpath.c')
-rw-r--r--drivers/md/dm-mpath.c49
1 files changed, 42 insertions, 7 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 638dae048b4f..d8abb90a6c2f 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -85,6 +85,7 @@ struct multipath {
unsigned queue_io:1; /* Must we queue all I/O? */
unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */
unsigned saved_queue_if_no_path:1; /* Saved state during suspension */
+ unsigned retain_attached_hw_handler:1; /* If there's already a hw_handler present, don't change it. */
unsigned pg_init_retries; /* Number of times to retry pg_init */
unsigned pg_init_count; /* Number of times pg_init called */
@@ -568,6 +569,8 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
int r;
struct pgpath *p;
struct multipath *m = ti->private;
+ struct request_queue *q = NULL;
+ const char *attached_handler_name;
/* we need at least a path arg */
if (as->argc < 1) {
@@ -586,13 +589,37 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
goto bad;
}
- if (m->hw_handler_name) {
- struct request_queue *q = bdev_get_queue(p->path.dev->bdev);
+ if (m->retain_attached_hw_handler || m->hw_handler_name)
+ q = bdev_get_queue(p->path.dev->bdev);
+
+ if (m->retain_attached_hw_handler) {
+ attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
+ if (attached_handler_name) {
+ /*
+ * Reset hw_handler_name to match the attached handler
+ * and clear any hw_handler_params associated with the
+ * ignored handler.
+ *
+ * NB. This modifies the table line to show the actual
+ * handler instead of the original table passed in.
+ */
+ kfree(m->hw_handler_name);
+ m->hw_handler_name = attached_handler_name;
+
+ kfree(m->hw_handler_params);
+ m->hw_handler_params = NULL;
+ }
+ }
+ if (m->hw_handler_name) {
+ /*
+ * Increments scsi_dh reference, even when using an
+ * already-attached handler.
+ */
r = scsi_dh_attach(q, m->hw_handler_name);
if (r == -EBUSY) {
/*
- * Already attached to different hw_handler,
+ * Already attached to different hw_handler:
* try to reattach with correct one.
*/
scsi_dh_detach(q);
@@ -760,7 +787,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
const char *arg_name;
static struct dm_arg _args[] = {
- {0, 5, "invalid number of feature args"},
+ {0, 6, "invalid number of feature args"},
{1, 50, "pg_init_retries must be between 1 and 50"},
{0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
};
@@ -781,6 +808,11 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
continue;
}
+ if (!strcasecmp(arg_name, "retain_attached_hw_handler")) {
+ m->retain_attached_hw_handler = 1;
+ continue;
+ }
+
if (!strcasecmp(arg_name, "pg_init_retries") &&
(argc >= 1)) {
r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
@@ -1346,7 +1378,7 @@ static void multipath_resume(struct dm_target *ti)
* num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
*/
static int multipath_status(struct dm_target *ti, status_type_t type,
- char *result, unsigned int maxlen)
+ unsigned status_flags, char *result, unsigned maxlen)
{
int sz = 0;
unsigned long flags;
@@ -1364,13 +1396,16 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
else {
DMEMIT("%u ", m->queue_if_no_path +
(m->pg_init_retries > 0) * 2 +
- (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2);
+ (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 +
+ m->retain_attached_hw_handler);
if (m->queue_if_no_path)
DMEMIT("queue_if_no_path ");
if (m->pg_init_retries)
DMEMIT("pg_init_retries %u ", m->pg_init_retries);
if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
+ if (m->retain_attached_hw_handler)
+ DMEMIT("retain_attached_hw_handler ");
}
if (!m->hw_handler_name || type == STATUSTYPE_INFO)
@@ -1656,7 +1691,7 @@ out:
*---------------------------------------------------------------*/
static struct target_type multipath_target = {
.name = "multipath",
- .version = {1, 4, 0},
+ .version = {1, 5, 0},
.module = THIS_MODULE,
.ctr = multipath_ctr,
.dtr = multipath_dtr,