[PATCH 5/5] target: perform alua group changes in one step
From: Mike Christie <michael.christie@oracle.com>
Date: 2021-09-30 02:04:44
Also in:
target-devel
Subsystem:
scsi target subsystem, the rest · Maintainers:
"Martin K. Petersen", Linus Torvalds
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 IO to execute. This has us skip the NULL stage, and just swap in the new group. Signed-off-by: Mike Christie <michael.christie@oracle.com> --- 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 74944b914b4e..b56ef8af66e7 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) ?
--
2.25.1