From f9793d649c29bad86651620ec49888ee9743cbb6 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Wed, 29 Sep 2021 21:04:22 -0500 Subject: [PATCH] scsi: target: Perform ALUA group changes in one step When userspace changes the LUN's ALUA group, it will set the LUN's group to NULL then to the new group. Before the new group is set, target_alua_state_check() will return 0 and allow the I/O to execute. This has us skip the NULL stage, and just swap in the new group. Link: https://lore.kernel.org/r/20210930020422.92578-6-michael.christie@oracle.com Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen --- drivers/target/target_core_alua.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c index 74944b9..b56ef8a 100644 --- a/drivers/target/target_core_alua.c +++ b/drivers/target/target_core_alua.c @@ -1835,8 +1835,6 @@ static void __target_detach_tg_pt_gp(struct se_lun *lun, list_del_init(&lun->lun_tg_pt_gp_link); tg_pt_gp->tg_pt_gp_members--; spin_unlock(&tg_pt_gp->tg_pt_gp_lock); - - rcu_assign_pointer(lun->lun_tg_pt_gp, NULL); } void target_detach_tg_pt_gp(struct se_lun *lun) @@ -1846,12 +1844,25 @@ void target_detach_tg_pt_gp(struct se_lun *lun) spin_lock(&lun->lun_tg_pt_gp_lock); tg_pt_gp = rcu_dereference_check(lun->lun_tg_pt_gp, lockdep_is_held(&lun->lun_tg_pt_gp_lock)); - if (tg_pt_gp) + if (tg_pt_gp) { __target_detach_tg_pt_gp(lun, tg_pt_gp); + rcu_assign_pointer(lun->lun_tg_pt_gp, NULL); + } spin_unlock(&lun->lun_tg_pt_gp_lock); synchronize_rcu(); } +static void target_swap_tg_pt_gp(struct se_lun *lun, + struct t10_alua_tg_pt_gp *old_tg_pt_gp, + struct t10_alua_tg_pt_gp *new_tg_pt_gp) +{ + assert_spin_locked(&lun->lun_tg_pt_gp_lock); + + if (old_tg_pt_gp) + __target_detach_tg_pt_gp(lun, old_tg_pt_gp); + __target_attach_tg_pt_gp(lun, new_tg_pt_gp); +} + ssize_t core_alua_show_tg_pt_gp_info(struct se_lun *lun, char *page) { struct config_item *tg_pt_ci; @@ -1941,18 +1952,16 @@ ssize_t core_alua_store_tg_pt_gp_info( &tg_pt_gp->tg_pt_gp_group.cg_item), tg_pt_gp->tg_pt_gp_id); - __target_detach_tg_pt_gp(lun, tg_pt_gp); - __target_attach_tg_pt_gp(lun, + target_swap_tg_pt_gp(lun, tg_pt_gp, dev->t10_alua.default_tg_pt_gp); spin_unlock(&lun->lun_tg_pt_gp_lock); goto sync_rcu; } - __target_detach_tg_pt_gp(lun, tg_pt_gp); move = 1; } - __target_attach_tg_pt_gp(lun, tg_pt_gp_new); + target_swap_tg_pt_gp(lun, tg_pt_gp, tg_pt_gp_new); spin_unlock(&lun->lun_tg_pt_gp_lock); pr_debug("Target_Core_ConfigFS: %s %s/tpgt_%hu/%s to ALUA" " Target Port Group: alua/%s, ID: %hu\n", (move) ? -- 2.7.4