Commit 1f48b065 authored by Mike Christie's avatar Mike Christie Committed by Martin K. Petersen
Browse files

scsi: target: xen-scsiback: Convert to new submission API 

target_submit_cmd_map_sgls() is being removed, so convert xen to the new
submission API. This has it use target_init_cmd(), target_submit_prep(), or
target_submit() because we need to have LIO core map sgls which is now done
in target_submit_prep(). target_init_cmd() will never fail for xen because
it does its own sync during session shutdown, so we can remove that code.

Note: xen never calls target_stop_session() so target_submit_cmd_map_sgls()
never failed (in the new API target_init_cmd() handles
target_stop_session() being called when cmds are being submitted). If it
were to have used target_stop_session() and got an error, we would have hit
a refcount bug like xen and usb, because it does:

    if (rc < 0) {
            transport_send_check_condition_and_sense(se_cmd,
                            TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
            transport_generic_free_cmd(se_cmd, 0);
    }

transport_send_check_condition_and_sense() calls queue_status which calls
scsiback_cmd_done->target_put_sess_cmd. We do an extra
transport_generic_free_cmd() call above which would have dropped the
refcount to -1 and the refcount code would spit out errors.

Link: https://lore.kernel.org/r/20210227170006.5077-13-michael.christie@oracle.com


Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent eb929804

drivers/xen/xen-scsiback.c

+9 −12
Original line number Diff line number Diff line
@@ -360,21 +360,18 @@ static void scsiback_cmd_exec(struct vscsibk_pend *pending_req) 
{

	struct se_cmd *se_cmd = &pending_req->se_cmd;

	struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;

	int rc;



	scsiback_get(pending_req->info);

	se_cmd->tag = pending_req->rqid;

	rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,

			pending_req->sense_buffer, pending_req->v2p->lun,

			pending_req->data_len, 0,

			pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,

			pending_req->sgl, pending_req->n_sg,

			NULL, 0, NULL, 0);

	if (rc < 0) {

		transport_send_check_condition_and_sense(se_cmd,

				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);

		transport_generic_free_cmd(se_cmd, 0);

	}

	target_init_cmd(se_cmd, sess, pending_req->sense_buffer,

			pending_req->v2p->lun, pending_req->data_len, 0,

			pending_req->sc_data_direction, TARGET_SCF_ACK_KREF);



	if (target_submit_prep(se_cmd, pending_req->cmnd, pending_req->sgl,

			       pending_req->n_sg, NULL, 0, NULL, 0))

		return;



	target_submit(se_cmd);

}



static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,