target: More core cleanups from AGrover (round 2)

This patch contains the squashed version of second round of target core
cleanups and simplifications and Andy and Co.   It also contains a handful
of fixes to address bugs the original series and other minor cleanups.

Here is the condensed shortlog:

target: Remove unneeded casts to void*
target: Rename get_lun_for_{cmd,tmr} to lookup_{cmd,tmr}_lun
target: Make t_task a member of se_cmd, not a pointer
target: Handle functions returning "-2"
target: Use cmd->se_dev over cmd->se_lun->lun_se_dev
target: Embed qr in struct se_cmd
target: Replace embedded struct se_queue_req with a list_head
target: Rename list_heads that are nodes in struct se_cmd to "*_node"
target: Fold transport_device_setup_cmd() into lookup_{tmr,cmd}_lun()
target: Make t_mem_list and t_mem_list_bidi members of t_task
target: Add comment & cleanup transport_map_sg_to_mem()
target: Remove unneeded checks in transport_free_pages()

(Roland: Fix se_queue_req removal leftovers OOPs)
(nab: Fix transport_lookup_tmr_lun failure case)
(nab: Fix list_empty(&cmd->t_task.t_mem_bidi_list) inversion bugs)

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 22 insertions, 34 deletions

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 2f19e1926493..eeb7ee7ab9f7 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -118,17 +118,16 @@ static struct se_cmd *tcm_loop_allocate_core_cmd(
          * Signal BIDI usage with T_TASK(cmd)->t_tasks_bidi
          */
         if (scsi_bidi_cmnd(sc))
-                se_cmd->t_task->t_tasks_bidi = 1;
+                se_cmd->t_task.t_tasks_bidi = 1;
         /*
          * Locate the struct se_lun pointer and attach it to struct se_cmd
          */
-        if (transport_get_lun_for_cmd(se_cmd, tl_cmd->sc->device->lun) < 0) {
+        if (transport_lookup_cmd_lun(se_cmd, tl_cmd->sc->device->lun) < 0) {
                 kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
                 set_host_byte(sc, DID_NO_CONNECT);
                 return NULL;
         }
 
-        transport_device_setup_cmd(se_cmd);
         return se_cmd;
 }
 
@@ -143,17 +142,17 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
         struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
                                 struct tcm_loop_cmd, tl_se_cmd);
         struct scsi_cmnd *sc = tl_cmd->sc;
-        void *mem_ptr, *mem_bidi_ptr = NULL;
-        u32 sg_no_bidi = 0;
+        struct scatterlist *sgl_bidi = NULL;
+        u32 sgl_bidi_count = 0;
         int ret;
         /*
          * Allocate the necessary tasks to complete the received CDB+data
          */
-        ret = transport_generic_allocate_tasks(se_cmd, tl_cmd->sc->cmnd);
-        if (ret == -1) {
+        ret = transport_generic_allocate_tasks(se_cmd, sc->cmnd);
+        if (ret == -ENOMEM) {
                 /* Out of Resources */
                 return PYX_TRANSPORT_LU_COMM_FAILURE;
-        } else if (ret == -2) {
+        } else if (ret == -EINVAL) {
                 /*
                  * Handle case for SAM_STAT_RESERVATION_CONFLICT
                  */
@@ -165,35 +164,24 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
                  */
                 return PYX_TRANSPORT_USE_SENSE_REASON;
         }
+
         /*
-         * Setup the struct scatterlist memory from the received
-         * struct scsi_cmnd.
+         * For BIDI commands, pass in the extra READ buffer
+         * to transport_generic_map_mem_to_cmd() below..
          */
-        if (scsi_sg_count(sc)) {
-                se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM;
-                mem_ptr = (void *)scsi_sglist(sc);
-                /*
-                 * For BIDI commands, pass in the extra READ buffer
-                 * to transport_generic_map_mem_to_cmd() below..
-                 */
-                if (se_cmd->t_task->t_tasks_bidi) {
-                        struct scsi_data_buffer *sdb = scsi_in(sc);
+        if (se_cmd->t_task.t_tasks_bidi) {
+                struct scsi_data_buffer *sdb = scsi_in(sc);
 
-                        mem_bidi_ptr = (void *)sdb->table.sgl;
-                        sg_no_bidi = sdb->table.nents;
-                }
-        } else {
-                /*
-                 * Used for DMA_NONE
-                 */
-                mem_ptr = NULL;
+                sgl_bidi = sdb->table.sgl;
+                sgl_bidi_count = sdb->table.nents;
         }
+
         /*
          * Map the SG memory into struct se_mem->page linked list using the same
          * physical memory at sg->page_link.
          */
-        ret = transport_generic_map_mem_to_cmd(se_cmd, mem_ptr,
-                        scsi_sg_count(sc), mem_bidi_ptr, sg_no_bidi);
+        ret = transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),
+                        scsi_sg_count(sc), sgl_bidi, sgl_bidi_count);
         if (ret < 0)
                 return PYX_TRANSPORT_LU_COMM_FAILURE;
 
@@ -384,14 +372,14 @@ static int tcm_loop_device_reset(struct scsi_cmnd *sc)
         /*
          * Allocate the LUN_RESET TMR
          */
-        se_cmd->se_tmr_req = core_tmr_alloc_req(se_cmd, (void *)tl_tmr,
+        se_cmd->se_tmr_req = core_tmr_alloc_req(se_cmd, tl_tmr,
                                 TMR_LUN_RESET);
         if (IS_ERR(se_cmd->se_tmr_req))
                 goto release;
         /*
          * Locate the underlying TCM struct se_lun from sc->device->lun
          */
-        if (transport_get_lun_for_tmr(se_cmd, sc->device->lun) < 0)
+        if (transport_lookup_tmr_lun(se_cmd, sc->device->lun) < 0)
                 goto release;
         /*
          * Queue the TMR to TCM Core and sleep waiting for tcm_loop_queue_tm_rsp()
@@ -904,7 +892,7 @@ static int tcm_loop_queue_status(struct se_cmd *se_cmd)
            ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
             (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
 
-                memcpy((void *)sc->sense_buffer, (void *)se_cmd->sense_buffer,
+                memcpy(sc->sense_buffer, se_cmd->sense_buffer,
                                 SCSI_SENSE_BUFFERSIZE);
                 sc->result = SAM_STAT_CHECK_CONDITION;
                 set_driver_byte(sc, DRIVER_SENSE);
@@ -1054,7 +1042,7 @@ static int tcm_loop_make_nexus(
          * transport_register_session()
          */
         __transport_register_session(se_tpg, tl_nexus->se_sess->se_node_acl,
-                        tl_nexus->se_sess, (void *)tl_nexus);
+                        tl_nexus->se_sess, tl_nexus);
         tl_tpg->tl_hba->tl_nexus = tl_nexus;
         printk(KERN_INFO "TCM_Loop_ConfigFS: Established I_T Nexus to emulated"
                 " %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
@@ -1242,7 +1230,7 @@ struct se_portal_group *tcm_loop_make_naa_tpg(
          * Register the tl_tpg as a emulated SAS TCM Target Endpoint
          */
         ret = core_tpg_register(&tcm_loop_fabric_configfs->tf_ops,
-                        wwn, &tl_tpg->tl_se_tpg, (void *)tl_tpg,
+                        wwn, &tl_tpg->tl_se_tpg, tl_tpg,
                         TRANSPORT_TPG_TYPE_NORMAL);
         if (ret < 0)
                 return ERR_PTR(-ENOMEM);