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

1 files changed, 8 insertions, 54 deletions

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 7a0da1ae0040..2d444b1ccd33 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -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: