Commit 9f0abc15 authored by Nicholas Bellinger's avatar Nicholas Bellinger
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tcm_vhost: Convert I/O path to use target_submit_cmd_map_sgls 



This patch converts tcm_vhost to use target_submit_cmd_map_sgls() for
I/O submission and mapping of pre-allocated SGL memory from incoming
virtio-scsi SGL memory -> se_cmd descriptors.

This includes removing the original open-coded fabric uses of target
core callers to support transport_generic_map_mem_to_cmd() between
target_setup_cmd_from_cdb() and transport_handle_cdb_direct() logic.

It also includes adding a handful of new tcm_vhost_cmnd member +
assignments in vhost_scsi_allocate_cmd() used from cmwq process
context I/O submission within tcm_vhost_submission_work()

(v2: Use renamed target_submit_cmd_map_sgls)

Reported-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 944981c7

drivers/vhost/tcm_vhost.c

+14 −54
Original line number Diff line number Diff line
@@ -415,10 +415,7 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd( 
{

	struct tcm_vhost_cmd *tv_cmd;

	struct tcm_vhost_nexus *tv_nexus;

	struct se_portal_group *se_tpg = &tv_tpg->se_tpg;

	struct se_session *se_sess;

	struct se_cmd *se_cmd;

	int sam_task_attr;



	tv_nexus = tv_tpg->tpg_nexus;

	if (!tv_nexus) {
@@ -434,23 +431,11 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd( 
	}

	INIT_LIST_HEAD(&tv_cmd->tvc_completion_list);

	tv_cmd->tvc_tag = v_req->tag;

	tv_cmd->tvc_task_attr = v_req->task_attr;

	tv_cmd->tvc_exp_data_len = exp_data_len;

	tv_cmd->tvc_data_direction = data_direction;

	tv_cmd->tvc_nexus = tv_nexus;



	se_cmd = &tv_cmd->tvc_se_cmd;

	/*

	 * Locate the SAM Task Attr from virtio_scsi_cmd_req

	 */

	sam_task_attr = v_req->task_attr;

	/*

	 * Initialize struct se_cmd descriptor from TCM infrastructure

	 */

	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, exp_data_len,

				data_direction, sam_task_attr,

				&tv_cmd->tvc_sense_buf[0]);



#if 0	/* FIXME: vhost_scsi_allocate_cmd() BIDI operation */

	if (bidi)

		se_cmd->se_cmd_flags |= SCF_BIDI;

#endif

	return tv_cmd;

}
@@ -549,37 +534,10 @@ static void tcm_vhost_submission_work(struct work_struct *work) 
{

	struct tcm_vhost_cmd *tv_cmd =

		container_of(work, struct tcm_vhost_cmd, work);

	struct tcm_vhost_nexus *tv_nexus;

	struct se_cmd *se_cmd = &tv_cmd->tvc_se_cmd;

	struct scatterlist *sg_ptr, *sg_bidi_ptr = NULL;

	int rc, sg_no_bidi = 0;

	/*

	 * Locate the struct se_lun pointer based on v_req->lun, and

	 * attach it to struct se_cmd

	 */

	rc = transport_lookup_cmd_lun(&tv_cmd->tvc_se_cmd, tv_cmd->tvc_lun);

	if (rc < 0) {

		pr_err("Failed to look up lun: %d\n", tv_cmd->tvc_lun);

		transport_send_check_condition_and_sense(&tv_cmd->tvc_se_cmd,

			tv_cmd->tvc_se_cmd.scsi_sense_reason, 0);

		transport_generic_free_cmd(se_cmd, 0);

		return;

	}



	rc = target_setup_cmd_from_cdb(se_cmd, tv_cmd->tvc_cdb);

	if (rc == -ENOMEM) {

		transport_send_check_condition_and_sense(se_cmd,

				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);

		transport_generic_free_cmd(se_cmd, 0);

		return;

	} else if (rc < 0) {

		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)

			tcm_vhost_queue_status(se_cmd);

		else

			transport_send_check_condition_and_sense(se_cmd,

					se_cmd->scsi_sense_reason, 0);

		transport_generic_free_cmd(se_cmd, 0);

		return;

	}



	if (tv_cmd->tvc_sgl_count) {

		sg_ptr = tv_cmd->tvc_sgl;
@@ -597,17 +555,19 @@ static void tcm_vhost_submission_work(struct work_struct *work) 
	} else {

		sg_ptr = NULL;

	}

	tv_nexus = tv_cmd->tvc_nexus;



	rc = transport_generic_map_mem_to_cmd(se_cmd, sg_ptr,

				tv_cmd->tvc_sgl_count, sg_bidi_ptr,

				sg_no_bidi);

	rc = target_submit_cmd_map_sgls(se_cmd, tv_nexus->tvn_se_sess,

			tv_cmd->tvc_cdb, &tv_cmd->tvc_sense_buf[0],

			tv_cmd->tvc_lun, tv_cmd->tvc_exp_data_len,

			tv_cmd->tvc_task_attr, tv_cmd->tvc_data_direction,

			0, sg_ptr, tv_cmd->tvc_sgl_count,

			sg_bidi_ptr, sg_no_bidi);

	if (rc < 0) {

		transport_send_check_condition_and_sense(se_cmd,

				se_cmd->scsi_sense_reason, 0);

				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);

		transport_generic_free_cmd(se_cmd, 0);

		return;

	}

	transport_handle_cdb_direct(se_cmd);

}



static void vhost_scsi_handle_vq(struct vhost_scsi *vs)

drivers/vhost/tcm_vhost.h

+8 −0
Original line number Diff line number Diff line
@@ -5,6 +5,12 @@ 
struct tcm_vhost_cmd {

	/* Descriptor from vhost_get_vq_desc() for virt_queue segment */

	int tvc_vq_desc;

	/* virtio-scsi initiator task attribute */

	int tvc_task_attr;

	/* virtio-scsi initiator data direction */

	enum dma_data_direction tvc_data_direction;

	/* Expected data transfer length from virtio-scsi header */

	u32 tvc_exp_data_len;

	/* The Tag from include/linux/virtio_scsi.h:struct virtio_scsi_cmd_req */

	u64 tvc_tag;

	/* The number of scatterlists associated with this cmd */
@@ -17,6 +23,8 @@ struct tcm_vhost_cmd { 
	struct virtio_scsi_cmd_resp __user *tvc_resp;

	/* Pointer to vhost_scsi for our device */

	struct vhost_scsi *tvc_vhost;

	/* Pointer to vhost nexus memory */

	struct tcm_vhost_nexus *tvc_nexus;

	/* The TCM I/O descriptor that is accessed via container_of() */

	struct se_cmd tvc_se_cmd;

	/* work item used for cmwq dispatch to tcm_vhost_submission_work() */

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