Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit afe2cb7f authored Feb 02, 2012 by Christoph Hellwig Committed by Nicholas Bellinger Feb 25, 2012

tcm_loop: defer all command submissions to workqueue



Apply the qla2xxx model of submitting all commands from a workqueue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

parent f872c9f4

drivers/target/loopback/tcm_loop.c

+57 −40

Original line number	Diff line number	Diff line
		@@ -44,6 +44,7 @@
		/* Local pointer to allocated TCM configfs fabric module */
		static struct target_fabric_configfs *tcm_loop_fabric_configfs;

		static struct workqueue_struct *tcm_loop_workqueue;
		static struct kmem_cache *tcm_loop_cmd_cache;

		static int tcm_loop_hba_no_cnt;
		@@ -206,32 +207,19 @@ static int tcm_loop_sam_attr(struct scsi_cmnd *sc)
		return MSG_SIMPLE_TAG;
		}

		/*
		* Main entry point from struct scsi_host_template for incoming SCSI CDB+Data
		* from Linux/SCSI subsystem for SCSI low level device drivers (LLDs)
		*/
		static int tcm_loop_queuecommand(
		struct Scsi_Host *sh,
		struct scsi_cmnd *sc)
		static void tcm_loop_submission_work(struct work_struct *work)
		{
		struct se_cmd *se_cmd;
		struct se_portal_group *se_tpg;
		struct tcm_loop_cmd *tl_cmd =
		container_of(work, struct tcm_loop_cmd, work);
		struct se_cmd *se_cmd = &tl_cmd->tl_se_cmd;
		struct scsi_cmnd *sc = tl_cmd->sc;
		struct tcm_loop_nexus *tl_nexus;
		struct tcm_loop_hba *tl_hba;
		struct tcm_loop_tpg *tl_tpg;
		struct se_session *se_sess;
		struct tcm_loop_nexus *tl_nexus;
		struct tcm_loop_cmd *tl_cmd;


		pr_debug("tcm_loop_queuecommand() %d:%d:%d:%d got CDB: 0x%02x"
		" scsi_buf_len: %u\n", sc->device->host->host_no,
		sc->device->id, sc->device->channel, sc->device->lun,
		sc->cmnd[0], scsi_bufflen(sc));
		/*
		* Locate the tcm_loop_hba_t pointer
		*/
		tl_hba = (struct tcm_loop_hba *)shost_priv(sc->device->host);
		tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];

		/*
		* Ensure that this tl_tpg reference from the incoming sc->device->id
		* has already been configured via tcm_loop_make_naa_tpg().
		@@ -240,7 +228,6 @@ static int tcm_loop_queuecommand(
		set_host_byte(sc, DID_NO_CONNECT);
		goto out_done;
		}
		se_tpg = &tl_tpg->tl_se_tpg;

		tl_nexus = tl_hba->tl_nexus;
		if (!tl_nexus) {
		@@ -249,18 +236,9 @@ static int tcm_loop_queuecommand(
		set_host_byte(sc, DID_ERROR);
		goto out_done;
		}
		se_sess = tl_nexus->se_sess;

		tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
		if (!tl_cmd) {
		pr_err("Unable to allocate struct tcm_loop_cmd\n");
		set_host_byte(sc, DID_ERROR);
		goto out_done;
		}
		se_cmd = &tl_cmd->tl_se_cmd;
		tl_cmd->sc = sc;

		transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
		transport_init_se_cmd(se_cmd, tl_tpg->tl_se_tpg.se_tpg_tfo,
		tl_nexus->se_sess,
		scsi_bufflen(sc), sc->sc_data_direction,
		tcm_loop_sam_attr(sc), &tl_cmd->tl_sense_buf[0]);

		@@ -274,10 +252,37 @@ static int tcm_loop_queuecommand(
		}

		transport_generic_handle_cdb_map(se_cmd);
		return 0;
		return;

		out_done:
		sc->scsi_done(sc);
		return;
		}

		/*
		* ->queuecommand can be and usually is called from interrupt context, so
		* defer the actual submission to a workqueue.
		*/
		static int tcm_loop_queuecommand(struct Scsi_Host sh, struct scsi_cmnd sc)
		{
		struct tcm_loop_cmd *tl_cmd;

		pr_debug("tcm_loop_queuecommand() %d:%d:%d:%d got CDB: 0x%02x"
		" scsi_buf_len: %u\n", sc->device->host->host_no,
		sc->device->id, sc->device->channel, sc->device->lun,
		sc->cmnd[0], scsi_bufflen(sc));

		tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
		if (!tl_cmd) {
		pr_err("Unable to allocate struct tcm_loop_cmd\n");
		set_host_byte(sc, DID_ERROR);
		sc->scsi_done(sc);
		return 0;
		}

		tl_cmd->sc = sc;
		INIT_WORK(&tl_cmd->work, tcm_loop_submission_work);
		queue_work(tcm_loop_workqueue, &tl_cmd->work);
		return 0;
		}

		@@ -1458,7 +1463,11 @@ static void tcm_loop_deregister_configfs(void)

		static int __init tcm_loop_fabric_init(void)
		{
		int ret;
		int ret = -ENOMEM;

		tcm_loop_workqueue = alloc_workqueue("tcm_loop", 0, 0);
		if (!tcm_loop_workqueue)
		goto out;

		tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
		sizeof(struct tcm_loop_cmd),
		@@ -1467,20 +1476,27 @@ static int __init tcm_loop_fabric_init(void)
		if (!tcm_loop_cmd_cache) {
		pr_debug("kmem_cache_create() for"
		" tcm_loop_cmd_cache failed\n");
		return -ENOMEM;
		goto out_destroy_workqueue;
		}

		ret = tcm_loop_alloc_core_bus();
		if (ret)
		return ret;
		goto out_destroy_cache;

		ret = tcm_loop_register_configfs();
		if (ret) {
		tcm_loop_release_core_bus();
		return ret;
		}
		if (ret)
		goto out_release_core_bus;

		return 0;

		out_release_core_bus:
		tcm_loop_release_core_bus();
		out_destroy_cache:
		kmem_cache_destroy(tcm_loop_cmd_cache);
		out_destroy_workqueue:
		destroy_workqueue(tcm_loop_workqueue);
		out:
		return ret;
		}

		static void __exit tcm_loop_fabric_exit(void)
		@@ -1488,6 +1504,7 @@ static void __exit tcm_loop_fabric_exit(void)
		tcm_loop_deregister_configfs();
		tcm_loop_release_core_bus();
		kmem_cache_destroy(tcm_loop_cmd_cache);
		destroy_workqueue(tcm_loop_workqueue);
		}

		MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");

drivers/target/loopback/tcm_loop.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -12,9 +12,9 @@ struct tcm_loop_cmd {
		u32 sc_cmd_state;
		/* Pointer to the CDB+Data descriptor from Linux/SCSI subsystem */
		struct scsi_cmnd *sc;
		struct list_head *tl_cmd_list;
		/* The TCM I/O descriptor that is accessed via container_of() */
		struct se_cmd tl_se_cmd;
		struct work_struct work;
		/* Sense buffer that will be mapped into outgoing status */
		unsigned char tl_sense_buf[TRANSPORT_SENSE_BUFFER];
		};