diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-03-23 06:42:19 +0300 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-06-01 10:23:46 +0300 |
| commit | 29a05deebf6c2e3010934fb78ee65cab3d329470 (patch) | |
| tree | 5b91d971e31c45919ef212513104350877807c3c /drivers/target/target_core_alua.c | |
| parent | d2c27f0d0b7eb18f40b9b1a0d793c8ba074e5c23 (diff) | |
| download | linux-29a05deebf6c2e3010934fb78ee65cab3d329470.tar.xz | |
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 <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_alua.c')
| -rw-r--r-- | drivers/target/target_core_alua.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c index b590f153a7b6..53cdfabac861 100644 --- a/drivers/target/target_core_alua.c +++ b/drivers/target/target_core_alua.c @@ -1001,7 +1001,8 @@ static void core_alua_do_transition_tg_pt_work(struct work_struct *work) spin_lock_bh(&port->sep_alua_lock); list_for_each_entry(se_deve, &port->sep_alua_list, alua_port_list) { - lacl = se_deve->se_lun_acl; + lacl = rcu_dereference_check(se_deve->se_lun_acl, + lockdep_is_held(&port->sep_alua_lock)); /* * se_deve->se_lun_acl pointer may be NULL for a * entry created without explicit Node+MappedLUN ACLs |