dm mpath: changes from initial m->flags locking audit

Fix locking in slow-paths where m->lock should be taken.

Signed-off-by: Mike Snitzer <snitzer@rredhat.com>

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 78cff42..d7bb74b 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -335,6 +335,8 @@ static int pg_init_all_paths(struct multipath *m)
 
 static void __switch_pg(struct multipath *m, struct priority_group *pg)
 {
+       lockdep_assert_held(&m->lock);
+
        m->current_pg = pg;
 
        /* Must we initialise the PG first, and queue I/O till it's ready? */
@@ -382,7 +384,9 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
        unsigned bypassed = 1;
 
        if (!atomic_read(&m->nr_valid_paths)) {
+               spin_lock_irqsave(&m->lock, flags);
                clear_bit(MPATHF_QUEUE_IO, &m->flags);
+               spin_unlock_irqrestore(&m->lock, flags);
                goto failed;
        }
 
@@ -422,8 +426,11 @@ check_current_pg:
                                continue;
                        pgpath = choose_path_in_pg(m, pg, nr_bytes);
                        if (!IS_ERR_OR_NULL(pgpath)) {
-                               if (!bypassed)
+                               if (!bypassed) {
+                                       spin_lock_irqsave(&m->lock, flags);
                                        set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
+                                       spin_unlock_irqrestore(&m->lock, flags);
+                               }
                                return pgpath;
                        }
                }
@@ -1662,9 +1669,9 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone,
 
        spin_lock_irqsave(&m->lock, flags);
        bio_list_add(&m->queued_bios, clone);
-       spin_unlock_irqrestore(&m->lock, flags);
        if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
                queue_work(kmultipathd, &m->process_queued_bios);
+       spin_unlock_irqrestore(&m->lock, flags);
 
        r = DM_ENDIO_INCOMPLETE;
 done:
@@ -1938,6 +1945,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
 {
        struct multipath *m = ti->private;
        struct pgpath *current_pgpath;
+       unsigned long flags;
        int r;
 
        current_pgpath = READ_ONCE(m->current_pgpath);
@@ -1965,8 +1973,10 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
                        /* Path status changed, redo selection */
                        (void) choose_pgpath(m, 0);
                }
+               spin_lock_irqsave(&m->lock, flags);
                if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
-                       pg_init_all_paths(m);
+                       (void) __pg_init_all_paths(m);
+               spin_unlock_irqrestore(&m->lock, flags);
                dm_table_run_md_queue_async(m->ti->table);
                process_queued_io_list(m);
        }