target: Convert se_portal_group->tpg_lun_list[] to RCU hlist
This patch converts the fixed size se_portal_group->tpg_lun_list[]
to use modern RCU with hlist_head in order to support an arbitary
number of se_lun ports per target endpoint.
It includes dropping core_tpg_alloc_lun() from core_dev_add_lun(),
and calling it directly from target_fabric_make_lun() to allocate
a new se_lun. And add a new target_fabric_port_release() configfs
item callback to invoke kfree_rcu() to release memory during
se_lun->lun_group shutdown.
Also now that se_node_acl->lun_entry_hlist is using RCU, convert
existing tpg_lun_lock to struct mutex so core_tpg_add_node_to_devs()
can perform RCU updater logic without releasing ->tpg_lun_mutex.
Also, drop core_tpg_clear_object_luns() and it's single consumer
in iscsi-target, which is duplicating TPG LUN shutdown logic and
is current code results in a NOP.
Finally, sbp-target and xen-scsiback fabric driver conversions are
included, which are required due to the non-standard way they use
->tpg_lun_hlist.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Chris Boot <bootc@bootc.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index 0939a54..9be8030 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -81,7 +81,7 @@
struct se_lun_acl, se_lun_group);
struct se_portal_group *se_tpg;
struct config_item *nacl_ci, *tpg_ci, *tpg_ci_s, *wwn_ci, *wwn_ci_s;
- int ret = 0, lun_access;
+ int lun_access;
if (lun->lun_link_magic != SE_LUN_LINK_MAGIC) {
pr_err("Bad lun->lun_link_magic, not a valid lun_ci pointer:"
@@ -137,12 +137,9 @@
* Determine the actual mapped LUN value user wants..
*
* This value is what the SCSI Initiator actually sees the
- * iscsi/$IQN/$TPGT/lun/lun_* as on their SCSI Initiator Ports.
+ * $FABRIC/$WWPN/$TPGT/lun/lun_* as on their SCSI Initiator Ports.
*/
- ret = core_dev_add_initiator_node_lun_acl(se_tpg, lacl,
- lun->unpacked_lun, lun_access);
-
- return (ret < 0) ? -EINVAL : 0;
+ return core_dev_add_initiator_node_lun_acl(se_tpg, lacl, lun, lun_access);
}
static int target_fabric_mappedlun_unlink(
@@ -761,7 +758,6 @@
struct config_item *tpg_ci;
struct se_lun *lun = container_of(to_config_group(lun_ci),
struct se_lun, lun_group);
- struct se_lun *lun_p;
struct se_portal_group *se_tpg;
struct se_device *dev =
container_of(to_config_group(se_dev_ci), struct se_device, dev_group);
@@ -789,10 +785,9 @@
return -EEXIST;
}
- lun_p = core_dev_add_lun(se_tpg, dev, lun->unpacked_lun);
- if (IS_ERR(lun_p)) {
- pr_err("core_dev_add_lun() failed\n");
- ret = PTR_ERR(lun_p);
+ ret = core_dev_add_lun(se_tpg, dev, lun);
+ if (ret) {
+ pr_err("core_dev_add_lun() failed: %d\n", ret);
goto out;
}
@@ -832,9 +827,18 @@
return 0;
}
+static void target_fabric_port_release(struct config_item *item)
+{
+ struct se_lun *lun = container_of(to_config_group(item),
+ struct se_lun, lun_group);
+
+ kfree_rcu(lun, rcu_head);
+}
+
static struct configfs_item_operations target_fabric_port_item_ops = {
.show_attribute = target_fabric_port_attr_show,
.store_attribute = target_fabric_port_attr_store,
+ .release = target_fabric_port_release,
.allow_link = target_fabric_port_link,
.drop_link = target_fabric_port_unlink,
};
@@ -893,15 +897,16 @@
if (unpacked_lun > UINT_MAX)
return ERR_PTR(-EINVAL);
- lun = core_get_lun_from_tpg(se_tpg, unpacked_lun);
- if (!lun)
- return ERR_PTR(-EINVAL);
+ lun = core_tpg_alloc_lun(se_tpg, unpacked_lun);
+ if (IS_ERR(lun))
+ return ERR_CAST(lun);
lun_cg = &lun->lun_group;
lun_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
GFP_KERNEL);
if (!lun_cg->default_groups) {
pr_err("Unable to allocate lun_cg->default_groups\n");
+ kfree(lun);
return ERR_PTR(-ENOMEM);
}
@@ -918,6 +923,7 @@
if (!port_stat_grp->default_groups) {
pr_err("Unable to allocate port_stat_grp->default_groups\n");
kfree(lun_cg->default_groups);
+ kfree(lun);
return ERR_PTR(-ENOMEM);
}
target_stat_setup_port_default_groups(lun);