diff options
| -rw-r--r-- | drivers/target/target_core_device.c | 10 | ||||
| -rw-r--r-- | drivers/target/target_core_tpg.c | 3 | ||||
| -rw-r--r-- | drivers/target/target_core_transport.c | 31 | ||||
| -rw-r--r-- | include/target/target_core_base.h | 1 |
4 files changed, 41 insertions, 4 deletions
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index cb7047d66afc..c754ae33bf7b 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -78,12 +78,16 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u64 unpacked_lun) &deve->read_bytes); se_lun = rcu_dereference(deve->se_lun); + + if (!percpu_ref_tryget_live(&se_lun->lun_ref)) { + se_lun = NULL; + goto out_unlock; + } + se_cmd->se_lun = rcu_dereference(deve->se_lun); se_cmd->pr_res_key = deve->pr_res_key; se_cmd->orig_fe_lun = unpacked_lun; se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD; - - percpu_ref_get(&se_lun->lun_ref); se_cmd->lun_ref_active = true; if ((se_cmd->data_direction == DMA_TO_DEVICE) && @@ -97,6 +101,7 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u64 unpacked_lun) goto ref_dev; } } +out_unlock: rcu_read_unlock(); if (!se_lun) { @@ -815,6 +820,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name) xcopy_lun = &dev->xcopy_lun; rcu_assign_pointer(xcopy_lun->lun_se_dev, dev); init_completion(&xcopy_lun->lun_ref_comp); + init_completion(&xcopy_lun->lun_shutdown_comp); INIT_LIST_HEAD(&xcopy_lun->lun_deve_list); INIT_LIST_HEAD(&xcopy_lun->lun_dev_link); mutex_init(&xcopy_lun->lun_tg_pt_md_mutex); diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index d99752c6cd60..2744251178ad 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -445,7 +445,7 @@ static void core_tpg_lun_ref_release(struct percpu_ref *ref) { struct se_lun *lun = container_of(ref, struct se_lun, lun_ref); - complete(&lun->lun_ref_comp); + complete(&lun->lun_shutdown_comp); } int core_tpg_register( @@ -571,6 +571,7 @@ struct se_lun *core_tpg_alloc_lun( lun->lun_link_magic = SE_LUN_LINK_MAGIC; atomic_set(&lun->lun_acl_count, 0); init_completion(&lun->lun_ref_comp); + init_completion(&lun->lun_shutdown_comp); INIT_LIST_HEAD(&lun->lun_deve_list); INIT_LIST_HEAD(&lun->lun_dev_link); atomic_set(&lun->lun_tg_pt_secondary_offline, 0); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index efb9e6f38201..434d9d693989 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2700,10 +2700,39 @@ void target_wait_for_sess_cmds(struct se_session *se_sess) } EXPORT_SYMBOL(target_wait_for_sess_cmds); +static void target_lun_confirm(struct percpu_ref *ref) +{ + struct se_lun *lun = container_of(ref, struct se_lun, lun_ref); + + complete(&lun->lun_ref_comp); +} + void transport_clear_lun_ref(struct se_lun *lun) { - percpu_ref_kill(&lun->lun_ref); + /* + * Mark the percpu-ref as DEAD, switch to atomic_t mode, drop + * the initial reference and schedule confirm kill to be + * executed after one full RCU grace period has completed. + */ + percpu_ref_kill_and_confirm(&lun->lun_ref, target_lun_confirm); + /* + * The first completion waits for percpu_ref_switch_to_atomic_rcu() + * to call target_lun_confirm after lun->lun_ref has been marked + * as __PERCPU_REF_DEAD on all CPUs, and switches to atomic_t + * mode so that percpu_ref_tryget_live() lookup of lun->lun_ref + * fails for all new incoming I/O. + */ wait_for_completion(&lun->lun_ref_comp); + /* + * The second completion waits for percpu_ref_put_many() to + * invoke ->release() after lun->lun_ref has switched to + * atomic_t mode, and lun->lun_ref.count has reached zero. + * + * At this point all target-core lun->lun_ref references have + * been dropped via transport_lun_remove_cmd(), and it's safe + * to proceed with the remaining LUN shutdown. + */ + wait_for_completion(&lun->lun_shutdown_comp); } static bool diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index d7336f3c6b60..16d3be8395be 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -730,6 +730,7 @@ struct se_lun { struct config_group lun_group; struct se_port_stat_grps port_stat_grps; struct completion lun_ref_comp; + struct completion lun_shutdown_comp; struct percpu_ref lun_ref; struct list_head lun_dev_link; struct hlist_node link; |