]> Pileus Git - ~andy/linux/blobdiff - drivers/target/target_core_transport.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git...
[~andy/linux] / drivers / target / target_core_transport.c
index 804dda90907e9239c2fb5ded40558d9123f1d960..3400ae6e93f83d2ae5b25395b97bbd6158877ec0 100644 (file)
@@ -53,6 +53,7 @@
 #include <target/target_core_configfs.h>
 
 #include "target_core_alua.h"
+#include "target_core_cdb.h"
 #include "target_core_hba.h"
 #include "target_core_pr.h"
 #include "target_core_ua.h"
@@ -269,6 +270,9 @@ struct se_session *transport_init_session(void)
        }
        INIT_LIST_HEAD(&se_sess->sess_list);
        INIT_LIST_HEAD(&se_sess->sess_acl_list);
+       INIT_LIST_HEAD(&se_sess->sess_cmd_list);
+       INIT_LIST_HEAD(&se_sess->sess_wait_list);
+       spin_lock_init(&se_sess->sess_cmd_lock);
 
        return se_sess;
 }
@@ -515,13 +519,16 @@ static int transport_cmd_check_stop(
                         * Some fabric modules like tcm_loop can release
                         * their internally allocated I/O reference now and
                         * struct se_cmd now.
+                        *
+                        * Fabric modules are expected to return '1' here if the
+                        * se_cmd being passed is released at this point,
+                        * or zero if not being released.
                         */
                        if (cmd->se_tfo->check_stop_free != NULL) {
                                spin_unlock_irqrestore(
                                        &cmd->t_state_lock, flags);
 
-                               cmd->se_tfo->check_stop_free(cmd);
-                               return 1;
+                               return cmd->se_tfo->check_stop_free(cmd);
                        }
                }
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
@@ -731,6 +738,10 @@ void transport_complete_task(struct se_task *task, int success)
                complete(&task->task_stop_comp);
                return;
        }
+
+       if (!success)
+               cmd->t_tasks_failed = 1;
+
        /*
         * Decrement the outstanding t_task_cdbs_left count.  The last
         * struct se_task from struct se_cmd will complete itself into the
@@ -741,7 +752,7 @@ void transport_complete_task(struct se_task *task, int success)
                return;
        }
 
-       if (!success || cmd->t_tasks_failed) {
+       if (cmd->t_tasks_failed) {
                if (!task->task_error_status) {
                        task->task_error_status =
                                PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
@@ -909,7 +920,7 @@ void transport_remove_task_from_execute_queue(
 }
 
 /*
- * Handle QUEUE_FULL / -EAGAIN status
+ * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
  */
 
 static void target_qf_do_work(struct work_struct *work)
@@ -1499,11 +1510,12 @@ void transport_init_se_cmd(
        INIT_LIST_HEAD(&cmd->se_ordered_node);
        INIT_LIST_HEAD(&cmd->se_qf_node);
        INIT_LIST_HEAD(&cmd->se_queue_node);
-
+       INIT_LIST_HEAD(&cmd->se_cmd_list);
        INIT_LIST_HEAD(&cmd->t_task_list);
        init_completion(&cmd->transport_lun_fe_stop_comp);
        init_completion(&cmd->transport_lun_stop_comp);
        init_completion(&cmd->t_transport_stop_comp);
+       init_completion(&cmd->cmd_wait_comp);
        spin_lock_init(&cmd->t_state_lock);
        atomic_set(&cmd->transport_dev_active, 1);
 
@@ -1646,9 +1658,7 @@ int transport_handle_cdb_direct(
         * and call transport_generic_request_failure() if necessary..
         */
        ret = transport_generic_new_cmd(cmd);
-       if (ret == -EAGAIN)
-               return 0;
-       else if (ret < 0) {
+       if (ret < 0) {
                cmd->transport_error_status = ret;
                transport_generic_request_failure(cmd, 0,
                                (cmd->data_direction != DMA_TO_DEVICE));
@@ -1718,13 +1728,6 @@ int transport_generic_handle_tmr(
 }
 EXPORT_SYMBOL(transport_generic_handle_tmr);
 
-void transport_generic_free_cmd_intr(
-       struct se_cmd *cmd)
-{
-       transport_add_cmd_to_queue(cmd, TRANSPORT_FREE_CMD_INTR, false);
-}
-EXPORT_SYMBOL(transport_generic_free_cmd_intr);
-
 /*
  * If the task is active, request it to be stopped and sleep until it
  * has completed.
@@ -1887,7 +1890,7 @@ static void transport_generic_request_failure(
                                ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
 
                ret = cmd->se_tfo->queue_status(cmd);
-               if (ret == -EAGAIN)
+               if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
                goto check_stop;
        case PYX_TRANSPORT_USE_SENSE_REASON:
@@ -1914,7 +1917,7 @@ static void transport_generic_request_failure(
        else {
                ret = transport_send_check_condition_and_sense(cmd,
                                cmd->scsi_sense_reason, 0);
-               if (ret == -EAGAIN)
+               if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
        }
 
@@ -2154,62 +2157,20 @@ check_depth:
                atomic_set(&cmd->t_transport_sent, 1);
 
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-       /*
-        * The struct se_cmd->transport_emulate_cdb() function pointer is used
-        * to grab REPORT_LUNS and other CDBs we want to handle before they hit the
-        * struct se_subsystem_api->do_task() caller below.
-        */
-       if (cmd->transport_emulate_cdb) {
-               error = cmd->transport_emulate_cdb(cmd);
-               if (error != 0) {
-                       cmd->transport_error_status = error;
-                       spin_lock_irqsave(&cmd->t_state_lock, flags);
-                       task->task_flags &= ~TF_ACTIVE;
-                       spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-                       atomic_set(&cmd->t_transport_sent, 0);
-                       transport_stop_tasks_for_cmd(cmd);
-                       atomic_inc(&dev->depth_left);
-                       transport_generic_request_failure(cmd, 0, 1);
-                       goto check_depth;
-               }
-               /*
-                * Handle the successful completion for transport_emulate_cdb()
-                * for synchronous operation, following SCF_EMULATE_CDB_ASYNC
-                * Otherwise the caller is expected to complete the task with
-                * proper status.
-                */
-               if (!(cmd->se_cmd_flags & SCF_EMULATE_CDB_ASYNC)) {
-                       cmd->scsi_status = SAM_STAT_GOOD;
-                       task->task_scsi_status = GOOD;
-                       transport_complete_task(task, 1);
-               }
-       } else {
-               /*
-                * Currently for all virtual TCM plugins including IBLOCK, FILEIO and
-                * RAMDISK we use the internal transport_emulate_control_cdb() logic
-                * with struct se_subsystem_api callers for the primary SPC-3 TYPE_DISK
-                * LUN emulation code.
-                *
-                * For TCM/pSCSI and all other SCF_SCSI_DATA_SG_IO_CDB I/O tasks we
-                * call ->do_task() directly and let the underlying TCM subsystem plugin
-                * code handle the CDB emulation.
-                */
-               if ((dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV) &&
-                   (!(task->task_se_cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB)))
-                       error = transport_emulate_control_cdb(task);
-               else
-                       error = dev->transport->do_task(task);
 
-               if (error != 0) {
-                       cmd->transport_error_status = error;
-                       spin_lock_irqsave(&cmd->t_state_lock, flags);
-                       task->task_flags &= ~TF_ACTIVE;
-                       spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-                       atomic_set(&cmd->t_transport_sent, 0);
-                       transport_stop_tasks_for_cmd(cmd);
-                       atomic_inc(&dev->depth_left);
-                       transport_generic_request_failure(cmd, 0, 1);
-               }
+       if (cmd->execute_task)
+               error = cmd->execute_task(task);
+       else
+               error = dev->transport->do_task(task);
+       if (error != 0) {
+               cmd->transport_error_status = error;
+               spin_lock_irqsave(&cmd->t_state_lock, flags);
+               task->task_flags &= ~TF_ACTIVE;
+               spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+               atomic_set(&cmd->t_transport_sent, 0);
+               transport_stop_tasks_for_cmd(cmd);
+               atomic_inc(&dev->depth_left);
+               transport_generic_request_failure(cmd, 0, 1);
        }
 
        goto check_depth;
@@ -2643,6 +2604,13 @@ static int transport_generic_cmd_sequencer(
                 */
        }
 
+       /*
+        * If we operate in passthrough mode we skip most CDB emulation and
+        * instead hand the commands down to the physical SCSI device.
+        */
+       passthrough =
+               (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV);
+
        switch (cdb[0]) {
        case READ_6:
                sectors = transport_get_sectors_6(cdb, cmd, &sector_ret);
@@ -2722,9 +2690,12 @@ static int transport_generic_cmd_sequencer(
                cmd->t_task_lba = transport_lba_32(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
 
-               if (dev->transport->transport_type ==
-                               TRANSPORT_PLUGIN_PHBA_PDEV)
+               /*
+                * Do now allow BIDI commands for passthrough mode.
+                */
+               if (passthrough)
                        goto out_unsupported_cdb;
+
                /*
                 * Setup BIDI XOR callback to be run after I/O completion.
                 */
@@ -2733,13 +2704,6 @@ static int transport_generic_cmd_sequencer(
                break;
        case VARIABLE_LENGTH_CMD:
                service_action = get_unaligned_be16(&cdb[8]);
-               /*
-                * Determine if this is TCM/PSCSI device and we should disable
-                * internal emulation for this CDB.
-                */
-               passthrough = (dev->transport->transport_type ==
-                                       TRANSPORT_PLUGIN_PHBA_PDEV);
-
                switch (service_action) {
                case XDWRITEREAD_32:
                        sectors = transport_get_sectors_32(cdb, cmd, &sector_ret);
@@ -2753,8 +2717,12 @@ static int transport_generic_cmd_sequencer(
                        cmd->t_task_lba = transport_lba_64_ext(cdb);
                        cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
 
+                       /*
+                        * Do now allow BIDI commands for passthrough mode.
+                        */
                        if (passthrough)
                                goto out_unsupported_cdb;
+
                        /*
                         * Setup BIDI XOR callback to be run during after I/O
                         * completion.
@@ -2780,7 +2748,8 @@ static int transport_generic_cmd_sequencer(
 
                        if (target_check_write_same_discard(&cdb[10], dev) < 0)
                                goto out_invalid_cdb_field;
-
+                       if (!passthrough)
+                               cmd->execute_task = target_emulate_write_same;
                        break;
                default:
                        pr_err("VARIABLE_LENGTH_CMD service action"
@@ -2794,12 +2763,10 @@ static int transport_generic_cmd_sequencer(
                        /*
                         * Check for emulated MI_REPORT_TARGET_PGS.
                         */
-                       if (cdb[1] == MI_REPORT_TARGET_PGS) {
-                               cmd->transport_emulate_cdb =
-                               (su_dev->t10_alua.alua_type ==
-                                SPC3_ALUA_EMULATED) ?
-                               core_emulate_report_target_port_groups :
-                               NULL;
+                       if (cdb[1] == MI_REPORT_TARGET_PGS &&
+                           su_dev->t10_alua.alua_type == SPC3_ALUA_EMULATED) {
+                               cmd->execute_task =
+                                       target_emulate_report_target_port_groups;
                        }
                        size = (cdb[6] << 24) | (cdb[7] << 16) |
                               (cdb[8] << 8) | cdb[9];
@@ -2820,8 +2787,15 @@ static int transport_generic_cmd_sequencer(
        case MODE_SENSE:
                size = cdb[4];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_modesense;
                break;
        case MODE_SENSE_10:
+               size = (cdb[7] << 8) + cdb[8];
+               cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_modesense;
+               break;
        case GPCMD_READ_BUFFER_CAPACITY:
        case GPCMD_SEND_OPC:
        case LOG_SELECT:
@@ -2841,11 +2815,14 @@ static int transport_generic_cmd_sequencer(
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case PERSISTENT_RESERVE_IN:
+               if (su_dev->t10_pr.res_type == SPC3_PERSISTENT_RESERVATIONS)
+                       cmd->execute_task = target_scsi3_emulate_pr_in;
+               size = (cdb[7] << 8) + cdb[8];
+               cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               break;
        case PERSISTENT_RESERVE_OUT:
-               cmd->transport_emulate_cdb =
-                       (su_dev->t10_pr.res_type ==
-                        SPC3_PERSISTENT_RESERVATIONS) ?
-                       core_scsi3_emulate_pr : NULL;
+               if (su_dev->t10_pr.res_type == SPC3_PERSISTENT_RESERVATIONS)
+                       cmd->execute_task = target_scsi3_emulate_pr_out;
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
@@ -2864,12 +2841,10 @@ static int transport_generic_cmd_sequencer(
                         *
                         * Check for emulated MO_SET_TARGET_PGS.
                         */
-                       if (cdb[1] == MO_SET_TARGET_PGS) {
-                               cmd->transport_emulate_cdb =
-                               (su_dev->t10_alua.alua_type ==
-                                       SPC3_ALUA_EMULATED) ?
-                               core_emulate_set_target_port_groups :
-                               NULL;
+                       if (cdb[1] == MO_SET_TARGET_PGS &&
+                           su_dev->t10_alua.alua_type == SPC3_ALUA_EMULATED) {
+                               cmd->execute_task =
+                                       target_emulate_set_target_port_groups;
                        }
 
                        size = (cdb[6] << 24) | (cdb[7] << 16) |
@@ -2889,6 +2864,8 @@ static int transport_generic_cmd_sequencer(
                if (cmd->se_dev->dev_task_attr_type == SAM_TASK_ATTR_EMULATED)
                        cmd->sam_task_attr = MSG_HEAD_TAG;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_inquiry;
                break;
        case READ_BUFFER:
                size = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
@@ -2897,6 +2874,8 @@ static int transport_generic_cmd_sequencer(
        case READ_CAPACITY:
                size = READ_CAP_LEN;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_readcapacity;
                break;
        case READ_MEDIA_SERIAL_NUMBER:
        case SECURITY_PROTOCOL_IN:
@@ -2905,6 +2884,21 @@ static int transport_generic_cmd_sequencer(
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case SERVICE_ACTION_IN:
+               switch (cmd->t_task_cdb[1] & 0x1f) {
+               case SAI_READ_CAPACITY_16:
+                       if (!passthrough)
+                               cmd->execute_task =
+                                       target_emulate_readcapacity_16;
+                       break;
+               default:
+                       if (passthrough)
+                               break;
+
+                       pr_err("Unsupported SA: 0x%02x\n",
+                               cmd->t_task_cdb[1] & 0x1f);
+                       goto out_unsupported_cdb;
+               }
+               /*FALLTHROUGH*/
        case ACCESS_CONTROL_IN:
        case ACCESS_CONTROL_OUT:
        case EXTENDED_COPY:
@@ -2935,6 +2929,8 @@ static int transport_generic_cmd_sequencer(
        case REQUEST_SENSE:
                size = cdb[4];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_request_sense;
                break;
        case READ_ELEMENT_STATUS:
                size = 65536 * cdb[7] + 256 * cdb[8] + cdb[9];
@@ -2962,10 +2958,8 @@ static int transport_generic_cmd_sequencer(
                 * is running in SPC_PASSTHROUGH, and wants reservations
                 * emulation disabled.
                 */
-               cmd->transport_emulate_cdb =
-                               (su_dev->t10_pr.res_type !=
-                                SPC_PASSTHROUGH) ?
-                               core_scsi2_emulate_crh : NULL;
+               if (su_dev->t10_pr.res_type != SPC_PASSTHROUGH)
+                       cmd->execute_task = target_scsi2_reservation_reserve;
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                break;
        case RELEASE:
@@ -2979,10 +2973,8 @@ static int transport_generic_cmd_sequencer(
                else
                        size = cmd->data_length;
 
-               cmd->transport_emulate_cdb =
-                               (su_dev->t10_pr.res_type !=
-                                SPC_PASSTHROUGH) ?
-                               core_scsi2_emulate_crh : NULL;
+               if (su_dev->t10_pr.res_type != SPC_PASSTHROUGH)
+                       cmd->execute_task = target_scsi2_reservation_release;
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                break;
        case SYNCHRONIZE_CACHE:
@@ -3003,16 +2995,9 @@ static int transport_generic_cmd_sequencer(
                size = transport_get_size(sectors, cdb, cmd);
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
 
-               /*
-                * For TCM/pSCSI passthrough, skip cmd->transport_emulate_cdb()
-                */
-               if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV)
+               if (passthrough)
                        break;
-               /*
-                * Set SCF_EMULATE_CDB_ASYNC to ensure asynchronous operation
-                * for SYNCHRONIZE_CACHE* Immed=1 case in __transport_execute_tasks()
-                */
-               cmd->se_cmd_flags |= SCF_EMULATE_CDB_ASYNC;
+
                /*
                 * Check to ensure that LBA + Range does not exceed past end of
                 * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
@@ -3021,10 +3006,13 @@ static int transport_generic_cmd_sequencer(
                        if (transport_cmd_get_valid_sectors(cmd) < 0)
                                goto out_invalid_cdb_field;
                }
+               cmd->execute_task = target_emulate_synchronize_cache;
                break;
        case UNMAP:
                size = get_unaligned_be16(&cdb[7]);
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_unmap;
                break;
        case WRITE_SAME_16:
                sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
@@ -3043,6 +3031,8 @@ static int transport_generic_cmd_sequencer(
 
                if (target_check_write_same_discard(&cdb[1], dev) < 0)
                        goto out_invalid_cdb_field;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_write_same;
                break;
        case WRITE_SAME:
                sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
@@ -3064,26 +3054,31 @@ static int transport_generic_cmd_sequencer(
                 */
                if (target_check_write_same_discard(&cdb[1], dev) < 0)
                        goto out_invalid_cdb_field;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_write_same;
                break;
        case ALLOW_MEDIUM_REMOVAL:
-       case GPCMD_CLOSE_TRACK:
        case ERASE:
-       case INITIALIZE_ELEMENT_STATUS:
-       case GPCMD_LOAD_UNLOAD:
        case REZERO_UNIT:
        case SEEK_10:
-       case GPCMD_SET_SPEED:
        case SPACE:
        case START_STOP:
        case TEST_UNIT_READY:
        case VERIFY:
        case WRITE_FILEMARKS:
+               cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
+               if (!passthrough)
+                       cmd->execute_task = target_emulate_noop;
+               break;
+       case GPCMD_CLOSE_TRACK:
+       case INITIALIZE_ELEMENT_STATUS:
+       case GPCMD_LOAD_UNLOAD:
+       case GPCMD_SET_SPEED:
        case MOVE_MEDIUM:
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                break;
        case REPORT_LUNS:
-               cmd->transport_emulate_cdb =
-                               transport_core_report_lun_response;
+               cmd->execute_task = target_report_luns;
                size = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
                /*
                 * Do implict HEAD_OF_QUEUE processing for REPORT_LUNS
@@ -3135,6 +3130,11 @@ static int transport_generic_cmd_sequencer(
                cmd->data_length = size;
        }
 
+       /* reject any command that we don't have a handler for */
+       if (!(passthrough || cmd->execute_task ||
+            (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB)))
+               goto out_unsupported_cdb;
+
        /* Let's limit control cdbs to a page, for simplicity's sake. */
        if ((cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB) &&
            size > PAGE_SIZE)
@@ -3309,7 +3309,7 @@ static void target_complete_ok_work(struct work_struct *work)
                if (cmd->scsi_status) {
                        ret = transport_send_check_condition_and_sense(
                                        cmd, reason, 1);
-                       if (ret == -EAGAIN)
+                       if (ret == -EAGAIN || ret == -ENOMEM)
                                goto queue_full;
 
                        transport_lun_remove_cmd(cmd);
@@ -3334,7 +3334,7 @@ static void target_complete_ok_work(struct work_struct *work)
                spin_unlock(&cmd->se_lun->lun_sep_lock);
 
                ret = cmd->se_tfo->queue_data_in(cmd);
-               if (ret == -EAGAIN)
+               if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
                break;
        case DMA_TO_DEVICE:
@@ -3355,14 +3355,14 @@ static void target_complete_ok_work(struct work_struct *work)
                        }
                        spin_unlock(&cmd->se_lun->lun_sep_lock);
                        ret = cmd->se_tfo->queue_data_in(cmd);
-                       if (ret == -EAGAIN)
+                       if (ret == -EAGAIN || ret == -ENOMEM)
                                goto queue_full;
                        break;
                }
                /* Fall through for DMA_TO_DEVICE */
        case DMA_NONE:
                ret = cmd->se_tfo->queue_status(cmd);
-               if (ret == -EAGAIN)
+               if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
                break;
        default:
@@ -3891,7 +3891,10 @@ EXPORT_SYMBOL(transport_generic_process_write);
 
 static void transport_write_pending_qf(struct se_cmd *cmd)
 {
-       if (cmd->se_tfo->write_pending(cmd) == -EAGAIN) {
+       int ret;
+
+       ret = cmd->se_tfo->write_pending(cmd);
+       if (ret == -EAGAIN || ret == -ENOMEM) {
                pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
                         cmd);
                transport_handle_queue_full(cmd, cmd->se_dev);
@@ -3921,7 +3924,7 @@ static int transport_generic_write_pending(struct se_cmd *cmd)
         * frontend know that WRITE buffers are ready.
         */
        ret = cmd->se_tfo->write_pending(cmd);
-       if (ret == -EAGAIN)
+       if (ret == -EAGAIN || ret == -ENOMEM)
                goto queue_full;
        else if (ret < 0)
                return ret;
@@ -3932,7 +3935,7 @@ queue_full:
        pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
        cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
        transport_handle_queue_full(cmd, cmd->se_dev);
-       return ret;
+       return 0;
 }
 
 /**
@@ -3950,6 +3953,14 @@ void transport_release_cmd(struct se_cmd *cmd)
                core_tmr_release_req(cmd->se_tmr_req);
        if (cmd->t_task_cdb != cmd->__t_task_cdb)
                kfree(cmd->t_task_cdb);
+       /*
+        * Check if target_wait_for_sess_cmds() is expecting to
+        * release se_cmd directly here..
+        */
+       if (cmd->check_release != 0 && cmd->se_tfo->check_release_cmd)
+               if (cmd->se_tfo->check_release_cmd(cmd) != 0)
+                       return;
+
        cmd->se_tfo->release_cmd(cmd);
 }
 EXPORT_SYMBOL(transport_release_cmd);
@@ -3977,6 +3988,114 @@ void transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
 }
 EXPORT_SYMBOL(transport_generic_free_cmd);
 
+/* target_get_sess_cmd - Add command to active ->sess_cmd_list
+ * @se_sess:   session to reference
+ * @se_cmd:    command descriptor to add
+ */
+void target_get_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
+       list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
+       se_cmd->check_release = 1;
+       spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+}
+EXPORT_SYMBOL(target_get_sess_cmd);
+
+/* target_put_sess_cmd - Check for active I/O shutdown or list delete
+ * @se_sess:   session to reference
+ * @se_cmd:    command descriptor to drop
+ */
+int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
+       if (list_empty(&se_cmd->se_cmd_list)) {
+               spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+               WARN_ON(1);
+               return 0;
+       }
+
+       if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
+               spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+               complete(&se_cmd->cmd_wait_comp);
+               return 1;
+       }
+       list_del(&se_cmd->se_cmd_list);
+       spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+
+       return 0;
+}
+EXPORT_SYMBOL(target_put_sess_cmd);
+
+/* target_splice_sess_cmd_list - Split active cmds into sess_wait_list
+ * @se_sess:   session to split
+ */
+void target_splice_sess_cmd_list(struct se_session *se_sess)
+{
+       struct se_cmd *se_cmd;
+       unsigned long flags;
+
+       WARN_ON(!list_empty(&se_sess->sess_wait_list));
+       INIT_LIST_HEAD(&se_sess->sess_wait_list);
+
+       spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
+       se_sess->sess_tearing_down = 1;
+
+       list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
+
+       list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
+               se_cmd->cmd_wait_set = 1;
+
+       spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+}
+EXPORT_SYMBOL(target_splice_sess_cmd_list);
+
+/* target_wait_for_sess_cmds - Wait for outstanding descriptors
+ * @se_sess:    session to wait for active I/O
+ * @wait_for_tasks:    Make extra transport_wait_for_tasks call
+ */
+void target_wait_for_sess_cmds(
+       struct se_session *se_sess,
+       int wait_for_tasks)
+{
+       struct se_cmd *se_cmd, *tmp_cmd;
+       bool rc = false;
+
+       list_for_each_entry_safe(se_cmd, tmp_cmd,
+                               &se_sess->sess_wait_list, se_cmd_list) {
+               list_del(&se_cmd->se_cmd_list);
+
+               pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
+                       " %d\n", se_cmd, se_cmd->t_state,
+                       se_cmd->se_tfo->get_cmd_state(se_cmd));
+
+               if (wait_for_tasks) {
+                       pr_debug("Calling transport_wait_for_tasks se_cmd: %p t_state: %d,"
+                               " fabric state: %d\n", se_cmd, se_cmd->t_state,
+                               se_cmd->se_tfo->get_cmd_state(se_cmd));
+
+                       rc = transport_wait_for_tasks(se_cmd);
+
+                       pr_debug("After transport_wait_for_tasks se_cmd: %p t_state: %d,"
+                               " fabric state: %d\n", se_cmd, se_cmd->t_state,
+                               se_cmd->se_tfo->get_cmd_state(se_cmd));
+               }
+
+               if (!rc) {
+                       wait_for_completion(&se_cmd->cmd_wait_comp);
+                       pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
+                               " fabric state: %d\n", se_cmd, se_cmd->t_state,
+                               se_cmd->se_tfo->get_cmd_state(se_cmd));
+               }
+
+               se_cmd->se_tfo->release_cmd(se_cmd);
+       }
+}
+EXPORT_SYMBOL(target_wait_for_sess_cmds);
+
 /*     transport_lun_wait_for_tasks():
  *
  *     Called from ConfigFS context to stop the passed struct se_cmd to allow
@@ -4153,14 +4272,14 @@ int transport_clear_lun_from_sessions(struct se_lun *lun)
  * Called from frontend fabric context to wait for storage engine
  * to pause and/or release frontend generated struct se_cmd.
  */
-void transport_wait_for_tasks(struct se_cmd *cmd)
+bool transport_wait_for_tasks(struct se_cmd *cmd)
 {
        unsigned long flags;
 
        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) && !(cmd->se_tmr_req)) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-               return;
+               return false;
        }
        /*
         * Only perform a possible wait_for_tasks if SCF_SUPPORTED_SAM_OPCODE
@@ -4168,7 +4287,7 @@ void transport_wait_for_tasks(struct se_cmd *cmd)
         */
        if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) && !cmd->se_tmr_req) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-               return;
+               return false;
        }
        /*
         * If we are already stopped due to an external event (ie: LUN shutdown)
@@ -4211,7 +4330,7 @@ void transport_wait_for_tasks(struct se_cmd *cmd)
        if (!atomic_read(&cmd->t_transport_active) ||
             atomic_read(&cmd->t_transport_aborted)) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-               return;
+               return false;
        }
 
        atomic_set(&cmd->t_transport_stop, 1);
@@ -4236,6 +4355,8 @@ void transport_wait_for_tasks(struct se_cmd *cmd)
                cmd->se_tfo->get_task_tag(cmd));
 
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+
+       return true;
 }
 EXPORT_SYMBOL(transport_wait_for_tasks);
 
@@ -4584,9 +4705,7 @@ get_cmd:
                                break;
                        }
                        ret = transport_generic_new_cmd(cmd);
-                       if (ret == -EAGAIN)
-                               break;
-                       else if (ret < 0) {
+                       if (ret < 0) {
                                cmd->transport_error_status = ret;
                                transport_generic_request_failure(cmd,
                                        0, (cmd->data_direction !=
@@ -4596,9 +4715,6 @@ get_cmd:
                case TRANSPORT_PROCESS_WRITE:
                        transport_generic_process_write(cmd);
                        break;
-               case TRANSPORT_FREE_CMD_INTR:
-                       transport_generic_free_cmd(cmd, 0);
-                       break;
                case TRANSPORT_PROCESS_TMR:
                        transport_generic_do_tmr(cmd);
                        break;