target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage

[cascardo/linux.git] / drivers / target / target_core_tpg.c

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index 499b139..5b30940 100644 (file)
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -102,7 +102,8 @@ void core_tpg_add_node_to_devs(
                if (lun_orig && lun != lun_orig)
                        continue;
 
-               dev = lun->lun_se_dev;
+               dev = rcu_dereference_check(lun->lun_se_dev,
+                                           lockdep_is_held(&tpg->tpg_lun_mutex));
                /*
                 * By default in LIO-Target $FABRIC_MOD,
                 * demo_mode_write_protect is ON, or READ_ONLY;
@@ -598,7 +599,6 @@ struct se_lun *core_tpg_alloc_lun(
        lun->unpacked_lun = unpacked_lun;
        lun->lun_link_magic = SE_LUN_LINK_MAGIC;
        atomic_set(&lun->lun_acl_count, 0);
-       spin_lock_init(&lun->lun_sep_lock);
        init_completion(&lun->lun_ref_comp);
        INIT_LIST_HEAD(&lun->lun_deve_list);
        INIT_LIST_HEAD(&lun->lun_dev_link);
@@ -636,12 +636,8 @@ int core_tpg_add_lun(
 
        mutex_lock(&tpg->tpg_lun_mutex);
 
-       spin_lock(&lun->lun_sep_lock);
-       lun->lun_index = dev->dev_index;
-       lun->lun_se_dev = dev;
-       spin_unlock(&lun->lun_sep_lock);
-
        spin_lock(&dev->se_port_lock);
+       lun->lun_index = dev->dev_index;
        rcu_assign_pointer(lun->lun_se_dev, dev);
        dev->export_count++;
        list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
@@ -664,7 +660,11 @@ void core_tpg_remove_lun(
        struct se_portal_group *tpg,
        struct se_lun *lun)
 {
-       struct se_device *dev = lun->lun_se_dev;
+       /*
+        * rcu_dereference_raw protected by se_lun->lun_group symlink
+        * reference to se_device->dev_group.
+        */
+       struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);
 
        core_clear_lun_from_tpg(lun, tpg);
        transport_clear_lun_ref(lun);