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Commit 8f9f44f8 authored by Nicholas Bellinger's avatar Nicholas Bellinger
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tcm_loop: Convert I/O path to use target_submit_cmd_map_sgls 



This patch converts tcm_loop to use target_submit_cmd_map_sgls() for
I/O submission and mapping of pre-allocated SGL memory from incoming
scsi_cmnd -> 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.

(v2: Use renamed target_submit_cmd_map_sgls)

Reported-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent a026757f

drivers/target/loopback/tcm_loop.c

+8 −54
Original line number Diff line number Diff line
@@ -166,7 +166,7 @@ static void tcm_loop_submission_work(struct work_struct *work) 
	struct tcm_loop_tpg *tl_tpg;

	struct scatterlist *sgl_bidi = NULL;

	u32 sgl_bidi_count = 0;

	int ret;

	int rc;



	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);

	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
@@ -187,12 +187,6 @@ static void tcm_loop_submission_work(struct work_struct *work) 
		set_host_byte(sc, DID_ERROR);

		goto out_done;

	}



	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]);



	if (scsi_bidi_cmnd(sc)) {

		struct scsi_data_buffer *sdb = scsi_in(sc);
@@ -201,56 +195,16 @@ static void tcm_loop_submission_work(struct work_struct *work) 
		se_cmd->se_cmd_flags |= SCF_BIDI;



	}



	if (transport_lookup_cmd_lun(se_cmd, tl_cmd->sc->device->lun) < 0) {

		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);

	rc = target_submit_cmd_map_sgls(se_cmd, tl_nexus->se_sess, sc->cmnd,

			&tl_cmd->tl_sense_buf[0], tl_cmd->sc->device->lun,

			scsi_bufflen(sc), tcm_loop_sam_attr(sc),

			sc->sc_data_direction, 0,

			scsi_sglist(sc), scsi_sg_count(sc),

			sgl_bidi, sgl_bidi_count);

	if (rc < 0) {

		set_host_byte(sc, DID_NO_CONNECT);

		goto out_done;

	}



	/*

	 * Because some userspace code via scsi-generic do not memset their

	 * associated read buffers, go ahead and do that here for type

	 * non-data CDBs.  Also note that this is currently guaranteed to be a

	 * single SGL for this case by target core in

	 * target_setup_cmd_from_cdb() -> transport_generic_cmd_sequencer().

	 */

	if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&

	    se_cmd->data_direction == DMA_FROM_DEVICE) {

		struct scatterlist *sg = scsi_sglist(sc);

		unsigned char *buf = kmap(sg_page(sg)) + sg->offset;



		if (buf != NULL) {

			memset(buf, 0, sg->length);

			kunmap(sg_page(sg));

		}

	}



	ret = target_setup_cmd_from_cdb(se_cmd, sc->cmnd);

	if (ret == -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 (ret < 0) {

		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)

			tcm_loop_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;

	}



	ret = transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),

			scsi_sg_count(sc), sgl_bidi, sgl_bidi_count);

	if (ret) {

		transport_send_check_condition_and_sense(se_cmd,

					se_cmd->scsi_sense_reason, 0);

		transport_generic_free_cmd(se_cmd, 0);

		return;

	}

	transport_handle_cdb_direct(se_cmd);

	return;



out_done: