| Message ID | 1496527808-28789-2-git-send-email-nab@linux-iscsi.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Looks good. Regards, Quinn Tran -----Original Message----- From: Nicholas Bellinger <nab@linux-iscsi.org> Date: Saturday, June 3, 2017 at 3:10 PM To: target-devel <target-devel@vger.kernel.org> Cc: linux-scsi <linux-scsi@vger.kernel.org>, lkml <linux-kernel@vger.kernel.org>, Nicholas Bellinger <nab@linux-iscsi.org>, "Madhani, Himanshu" <Himanshu.Madhani@cavium.com>, "Tran, Quinn" <Quinn.Tran@cavium.com>, Mike Christie <mchristi@redhat.com>, Hannes Reinecke <hare@suse.com>, Christoph Hellwig <hch@lst.de> Subject: [PATCH 1/3] target: Add support for TMR percpu reference counting From: Nicholas Bellinger <nab@linux-iscsi.org> 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. Cc: Himanshu Madhani <himanshu.madhani@cavium.com> Cc: 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> --- drivers/target/target_core_device.c | 14 ++++++++++---- drivers/target/target_core_transport.c | 3 +++ 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 8f0e0e3..11c80c4 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); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index f16a789..83bfc97 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1588,6 +1588,7 @@ static void target_complete_tmr_failure(struct work_struct *work) se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST; se_cmd->se_tfo->queue_tm_rsp(se_cmd); + transport_lun_remove_cmd(se_cmd); transport_cmd_check_stop_to_fabric(se_cmd); } @@ -3199,6 +3200,7 @@ static void target_tmr_work(struct work_struct *work) cmd->se_tfo->queue_tm_rsp(cmd); check_stop: + transport_lun_remove_cmd(cmd); transport_cmd_check_stop_to_fabric(cmd); } @@ -3221,6 +3223,7 @@ int transport_generic_handle_tmr( pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d" "ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function, cmd->se_tmr_req->ref_task_tag, cmd->tag); + transport_lun_remove_cmd(cmd); transport_cmd_check_stop_to_fabric(cmd); return 0; } -- 1.9.1
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 8f0e0e3..11c80c4 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); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index f16a789..83bfc97 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1588,6 +1588,7 @@ static void target_complete_tmr_failure(struct work_struct *work) se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST; se_cmd->se_tfo->queue_tm_rsp(se_cmd); + transport_lun_remove_cmd(se_cmd); transport_cmd_check_stop_to_fabric(se_cmd); } @@ -3199,6 +3200,7 @@ static void target_tmr_work(struct work_struct *work) cmd->se_tfo->queue_tm_rsp(cmd); check_stop: + transport_lun_remove_cmd(cmd); transport_cmd_check_stop_to_fabric(cmd); } @@ -3221,6 +3223,7 @@ int transport_generic_handle_tmr( pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d" "ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function, cmd->se_tmr_req->ref_task_tag, cmd->tag); + transport_lun_remove_cmd(cmd); transport_cmd_check_stop_to_fabric(cmd); return 0; }