diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2017-06-03 06:41:03 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2017-07-06 22:57:55 -0700 |
| commit | eeb64d239ea664592ff8f1bce5546209a6593df5 (patch) | |
| tree | adaa7dd7f68e731547b44d74c42c6bc9d4448bd4 /drivers/target/target_core_device.c | |
| parent | 12f66e4a0f7b5624901ba4301210e026c9ddf78d (diff) | |
target: Add support for TMR percpu reference counting
This patch introduces TMR percpu reference counting using
se_lun->lun_ref in transport_lookup_tmr_lun(), following
how existing non TMR per se_lun reference counting works
within transport_lookup_cmd_lun().
It also adds explicit transport_lun_remove_cmd() calls to
drop the reference in the three tmr related locations that
invoke transport_cmd_check_stop_to_fabric();
- target_tmr_work() during normal ->queue_tm_rsp()
- target_complete_tmr_failure() during error ->queue_tm_rsp()
- transport_generic_handle_tmr() during early failure
Also, note the exception paths in transport_generic_free_cmd()
and transport_cmd_finish_abort() already check SCF_SE_LUN_CMD,
and will invoke transport_lun_remove_cmd() when necessary.
Reviewed-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Quinn Tran <quinn.tran@cavium.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_device.c')
| -rw-r--r-- | drivers/target/target_core_device.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index e4771cec108c..bf7a57953fa4 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -168,11 +168,20 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u64 unpacked_lun) rcu_read_lock(); deve = target_nacl_find_deve(nacl, unpacked_lun); if (deve) { - se_cmd->se_lun = rcu_dereference(deve->se_lun); se_lun = rcu_dereference(deve->se_lun); + + if (!percpu_ref_tryget_live(&se_lun->lun_ref)) { + se_lun = NULL; + goto out_unlock; + } + + se_cmd->se_lun = rcu_dereference(deve->se_lun); se_cmd->pr_res_key = deve->pr_res_key; se_cmd->orig_fe_lun = unpacked_lun; + se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD; + se_cmd->lun_ref_active = true; } +out_unlock: rcu_read_unlock(); if (!se_lun) { @@ -182,9 +191,6 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u64 unpacked_lun) unpacked_lun); return -ENODEV; } - /* - * XXX: Add percpu se_lun->lun_ref reference count for TMR - */ se_cmd->se_dev = rcu_dereference_raw(se_lun->lun_se_dev); se_tmr->tmr_dev = rcu_dereference_raw(se_lun->lun_se_dev); |