From 29a05deebf6c2e3010934fb78ee65cab3d329470 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Sun, 22 Mar 2015 20:42:19 -0700 Subject: target: Convert se_node_acl->device_list[] to RCU hlist This patch converts se_node_acl->device_list[] table for mappedluns to modern RCU hlist_head usage in order to support an arbitrary number of node_acl lun mappings. It converts transport_lookup_*_lun() fast-path code to use RCU read path primitives when looking up se_dev_entry. It adds a new hlist_head at se_node_acl->lun_entry_hlist for this purpose. For transport_lookup_cmd_lun() code, it works with existing per-cpu se_lun->lun_ref when associating se_cmd with se_lun + se_device. Also, go ahead and update core_create_device_list_for_node() + core_free_device_list_for_node() to use ->lun_entry_hlist. It also converts se_dev_entry->pr_ref_count access to use modern struct kref counting, and updates core_disable_device_list_for_node() to kref_put() and block on se_deve->pr_comp waiting for outstanding PR special-case PR references to drop, then invoke kfree_rcu() to wait for the RCU grace period to complete before releasing memory. So now that se_node_acl->lun_entry_hlist fast path access uses RCU protected pointers, go ahead and convert remaining non-fast path RCU updater code using ->lun_entry_lock to struct mutex to allow callers to block while walking se_node_acl->lun_entry_hlist. Finally drop the left-over core_clear_initiator_node_from_tpg() that originally cleared lun_access during se_node_acl shutdown, as post RCU conversion it now becomes duplicated logic. Reviewed-by: Hannes Reinecke Cc: Christoph Hellwig Cc: Sagi Grimberg Cc: Paul E. McKenney Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_internal.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'drivers/target/target_core_internal.h') diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h index d0344ad9b0d8..a04a6e396ae3 100644 --- a/drivers/target/target_core_internal.h +++ b/drivers/target/target_core_internal.h @@ -9,13 +9,15 @@ extern struct mutex g_device_mutex; extern struct list_head g_device_list; struct se_dev_entry *core_get_se_deve_from_rtpi(struct se_node_acl *, u16); -int core_free_device_list_for_node(struct se_node_acl *, +void target_pr_kref_release(struct kref *); +void core_free_device_list_for_node(struct se_node_acl *, struct se_portal_group *); void core_update_device_list_access(u32, u32, struct se_node_acl *); +struct se_dev_entry *target_nacl_find_deve(struct se_node_acl *, u32); int core_enable_device_list_for_node(struct se_lun *, struct se_lun_acl *, u32, u32, struct se_node_acl *, struct se_portal_group *); -int core_disable_device_list_for_node(struct se_lun *, struct se_lun_acl *, - u32, u32, struct se_node_acl *, struct se_portal_group *); +void core_disable_device_list_for_node(struct se_lun *, struct se_dev_entry *, + struct se_node_acl *, struct se_portal_group *); void core_clear_lun_from_tpg(struct se_lun *, struct se_portal_group *); int core_dev_export(struct se_device *, struct se_portal_group *, struct se_lun *); -- cgit v1.2.3-55-g7522