scsi: target: core: De-RCU of se_lun and se_lun acl

se_lun and se_lun_acl are immutable pointers of struct se_dev_entry.
Remove RCU usage for access to those pointers.

Link: https://lore.kernel.org/r/20220727214125.19647-3-d.bogdanov@yadro.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index 58df014..fb91423 100644 (file)
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -934,8 +934,7 @@ static void core_alua_queue_state_change_ua(struct t10_alua_tg_pt_gp *tg_pt_gp)
 
                spin_lock(&lun->lun_deve_lock);
                list_for_each_entry(se_deve, &lun->lun_deve_list, lun_link) {
-                       lacl = rcu_dereference_check(se_deve->se_lun_acl,
-                                       lockdep_is_held(&lun->lun_deve_lock));
+                       lacl = se_deve->se_lun_acl;
 
                        /*
                         * spc4r37 p.242:

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 88a844a..b7f16ee 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -75,7 +75,7 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd)
                        return TCM_WRITE_PROTECTED;
                }
 
-               se_lun = rcu_dereference(deve->se_lun);
+               se_lun = deve->se_lun;
 
                if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
                        se_lun = NULL;
@@ -152,7 +152,7 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd)
        rcu_read_lock();
        deve = target_nacl_find_deve(nacl, se_cmd->orig_fe_lun);
        if (deve) {
-               se_lun = rcu_dereference(deve->se_lun);
+               se_lun = deve->se_lun;
 
                if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
                        se_lun = NULL;
@@ -216,7 +216,7 @@ struct se_dev_entry *core_get_se_deve_from_rtpi(
 
        rcu_read_lock();
        hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
-               lun = rcu_dereference(deve->se_lun);
+               lun = deve->se_lun;
                if (!lun) {
                        pr_err("%s device entries device pointer is"
                                " NULL, but Initiator has access.\n",
@@ -243,11 +243,8 @@ void core_free_device_list_for_node(
        struct se_dev_entry *deve;
 
        mutex_lock(&nacl->lun_entry_mutex);
-       hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
-               struct se_lun *lun = rcu_dereference_check(deve->se_lun,
-                                       lockdep_is_held(&nacl->lun_entry_mutex));
-               core_disable_device_list_for_node(lun, deve, nacl, tpg);
-       }
+       hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
+               core_disable_device_list_for_node(deve->se_lun, deve, nacl, tpg);
        mutex_unlock(&nacl->lun_entry_mutex);
 }
 
@@ -334,8 +331,7 @@ int core_enable_device_list_for_node(
        mutex_lock(&nacl->lun_entry_mutex);
        orig = target_nacl_find_deve(nacl, mapped_lun);
        if (orig && orig->se_lun) {
-               struct se_lun *orig_lun = rcu_dereference_check(orig->se_lun,
-                                       lockdep_is_held(&nacl->lun_entry_mutex));
+               struct se_lun *orig_lun = orig->se_lun;
 
                if (orig_lun != lun) {
                        pr_err("Existing orig->se_lun doesn't match new lun"
@@ -355,8 +351,8 @@ int core_enable_device_list_for_node(
                        return -EINVAL;
                }
 
-               rcu_assign_pointer(new->se_lun, lun);
-               rcu_assign_pointer(new->se_lun_acl, lun_acl);
+               new->se_lun = lun;
+               new->se_lun_acl = lun_acl;
                hlist_del_rcu(&orig->link);
                hlist_add_head_rcu(&new->link, &nacl->lun_entry_hlist);
                mutex_unlock(&nacl->lun_entry_mutex);
@@ -374,8 +370,8 @@ int core_enable_device_list_for_node(
                return 0;
        }
 
-       rcu_assign_pointer(new->se_lun, lun);
-       rcu_assign_pointer(new->se_lun_acl, lun_acl);
+       new->se_lun = lun;
+       new->se_lun_acl = lun_acl;
        hlist_add_head_rcu(&new->link, &nacl->lun_entry_hlist);
        mutex_unlock(&nacl->lun_entry_mutex);
 
@@ -454,10 +450,7 @@ void core_clear_lun_from_tpg(struct se_lun *lun, struct se_portal_group *tpg)
 
                mutex_lock(&nacl->lun_entry_mutex);
                hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
-                       struct se_lun *tmp_lun = rcu_dereference_check(deve->se_lun,
-                                       lockdep_is_held(&nacl->lun_entry_mutex));
-
-                       if (lun != tmp_lun)
+                       if (lun != deve->se_lun)
                                continue;
 
                        core_disable_device_list_for_node(lun, deve, nacl, tpg);

diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 3829b61..a1d6755 100644 (file)
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -739,8 +739,7 @@ static struct t10_pr_registration *__core_scsi3_alloc_registration(
                        if (!deve_tmp->se_lun_acl)
                                continue;
 
-                       lacl_tmp = rcu_dereference_check(deve_tmp->se_lun_acl,
-                                               lockdep_is_held(&lun_tmp->lun_deve_lock));
+                       lacl_tmp = deve_tmp->se_lun_acl;
                        nacl_tmp = lacl_tmp->se_lun_nacl;
                        /*
                         * Skip the matching struct se_node_acl that is allocated
@@ -784,8 +783,7 @@ static struct t10_pr_registration *__core_scsi3_alloc_registration(
                         * the original *pr_reg is processed in
                         * __core_scsi3_add_registration()
                         */
-                       dest_lun = rcu_dereference_check(deve_tmp->se_lun,
-                               kref_read(&deve_tmp->pr_kref) != 0);
+                       dest_lun = deve_tmp->se_lun;
 
                        pr_reg_atp = __core_scsi3_do_alloc_registration(dev,
                                                nacl_tmp, dest_lun, deve_tmp,
@@ -1437,34 +1435,26 @@ static void core_scsi3_nodeacl_undepend_item(struct se_node_acl *nacl)
 
 static int core_scsi3_lunacl_depend_item(struct se_dev_entry *se_deve)
 {
-       struct se_lun_acl *lun_acl;
-
        /*
         * For nacl->dynamic_node_acl=1
         */
-       lun_acl = rcu_dereference_check(se_deve->se_lun_acl,
-                               kref_read(&se_deve->pr_kref) != 0);
-       if (!lun_acl)
+       if (!se_deve->se_lun_acl)
                return 0;
 
-       return target_depend_item(&lun_acl->se_lun_group.cg_item);
+       return target_depend_item(&se_deve->se_lun_acl->se_lun_group.cg_item);
 }
 
 static void core_scsi3_lunacl_undepend_item(struct se_dev_entry *se_deve)
 {
-       struct se_lun_acl *lun_acl;
-
        /*
         * For nacl->dynamic_node_acl=1
         */
-       lun_acl = rcu_dereference_check(se_deve->se_lun_acl,
-                               kref_read(&se_deve->pr_kref) != 0);
-       if (!lun_acl) {
+       if (!se_deve->se_lun_acl) {
                kref_put(&se_deve->pr_kref, target_pr_kref_release);
                return;
        }
 
-       target_undepend_item(&lun_acl->se_lun_group.cg_item);
+       target_undepend_item(&se_deve->se_lun_acl->se_lun_group.cg_item);
        kref_put(&se_deve->pr_kref, target_pr_kref_release);
 }
 
@@ -1751,8 +1741,7 @@ core_scsi3_decode_spec_i_port(
                 * and then call __core_scsi3_add_registration() in the
                 * 2nd loop which will never fail.
                 */
-               dest_lun = rcu_dereference_check(dest_se_deve->se_lun,
-                               kref_read(&dest_se_deve->pr_kref) != 0);
+               dest_lun = dest_se_deve->se_lun;
 
                dest_pr_reg = __core_scsi3_alloc_registration(cmd->se_dev,
                                        dest_node_acl, dest_lun, dest_se_deve,
@@ -3446,8 +3435,7 @@ after_iport_check:
        dest_pr_reg = __core_scsi3_locate_pr_reg(dev, dest_node_acl,
                                        iport_ptr);
        if (!dest_pr_reg) {
-               struct se_lun *dest_lun = rcu_dereference_check(dest_se_deve->se_lun,
-                               kref_read(&dest_se_deve->pr_kref) != 0);
+               struct se_lun *dest_lun = dest_se_deve->se_lun;
 
                spin_unlock(&dev->dev_reservation_lock);
                if (core_scsi3_alloc_registration(cmd->se_dev, dest_node_acl,

diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c
index 62d15bc..f85ee5b 100644 (file)
--- a/drivers/target/target_core_stat.c
+++ b/drivers/target/target_core_stat.c
@@ -877,7 +877,6 @@ static ssize_t target_stat_auth_dev_show(struct config_item *item,
        struct se_lun_acl *lacl = auth_to_lacl(item);
        struct se_node_acl *nacl = lacl->se_lun_nacl;
        struct se_dev_entry *deve;
-       struct se_lun *lun;
        ssize_t ret;
 
        rcu_read_lock();
@@ -886,9 +885,9 @@ static ssize_t target_stat_auth_dev_show(struct config_item *item,
                rcu_read_unlock();
                return -ENODEV;
        }
-       lun = rcu_dereference(deve->se_lun);
+
        /* scsiDeviceIndex */
-       ret = snprintf(page, PAGE_SIZE, "%u\n", lun->lun_index);
+       ret = snprintf(page, PAGE_SIZE, "%u\n", deve->se_lun->lun_index);
        rcu_read_unlock();
        return ret;
 }
@@ -1217,7 +1216,6 @@ static ssize_t target_stat_iport_dev_show(struct config_item *item,
        struct se_lun_acl *lacl = iport_to_lacl(item);
        struct se_node_acl *nacl = lacl->se_lun_nacl;
        struct se_dev_entry *deve;
-       struct se_lun *lun;
        ssize_t ret;
 
        rcu_read_lock();
@@ -1226,9 +1224,9 @@ static ssize_t target_stat_iport_dev_show(struct config_item *item,
                rcu_read_unlock();
                return -ENODEV;
        }
-       lun = rcu_dereference(deve->se_lun);
+
        /* scsiDeviceIndex */
-       ret = snprintf(page, PAGE_SIZE, "%u\n", lun->lun_index);
+       ret = snprintf(page, PAGE_SIZE, "%u\n", deve->se_lun->lun_index);
        rcu_read_unlock();
        return ret;
 }

diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c
index 6bb20aa..8713cda 100644 (file)
--- a/drivers/target/target_core_xcopy.c
+++ b/drivers/target/target_core_xcopy.c
@@ -88,7 +88,7 @@ static int target_xcopy_locate_se_dev_e4(struct se_session *sess,
                struct se_device *this_dev;
                int rc;
 
-               this_lun = rcu_dereference(deve->se_lun);
+               this_lun = deve->se_lun;
                this_dev = rcu_dereference_raw(this_lun->lun_se_dev);
 
                rc = target_xcopy_locate_se_dev_e4_iter(this_dev, dev_wwn);

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index c2b36f7..8c92045 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -665,9 +665,9 @@ struct se_dev_entry {
        /* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */
        struct kref             pr_kref;
        struct completion       pr_comp;
-       struct se_lun_acl __rcu *se_lun_acl;
+       struct se_lun_acl       *se_lun_acl;
        spinlock_t              ua_lock;
-       struct se_lun __rcu     *se_lun;
+       struct se_lun           *se_lun;
 #define DEF_PR_REG_ACTIVE              1
        unsigned long           deve_flags;
        struct list_head        alua_port_list;