target: use ->exectute_task for all CDB emulation

Instead of calling into transport_emulate_control_cdb from
__transport_execute_tasks for some CDBs always set up ->exectute_tasks
in the command sequence and use it uniformly.

(nab: Add default passthrough break for SERVICE_ACTION_IN)

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

3 files changed, 97 insertions, 140 deletions

diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c
index 5a03085304e5..683ba02b8247 100644
--- a/drivers/target/target_core_cdb.c
+++ b/drivers/target/target_core_cdb.c
@@ -32,6 +32,7 @@
 #include <target/target_core_transport.h>
 #include <target/target_core_fabric_ops.h>
 #include "target_core_ua.h"
+#include "target_core_cdb.h"
 
 static void
 target_fill_alua_data(struct se_port *port, unsigned char *buf)
@@ -679,8 +680,7 @@ target_emulate_evpd_00(struct se_cmd *cmd, unsigned char *buf)
         return 0;
 }
 
-static int
-target_emulate_inquiry(struct se_task *task)
+int target_emulate_inquiry(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         struct se_device *dev = cmd->se_dev;
@@ -731,8 +731,7 @@ out:
         return ret;
 }
 
-static int
-target_emulate_readcapacity(struct se_task *task)
+int target_emulate_readcapacity(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         struct se_device *dev = cmd->se_dev;
@@ -768,8 +767,7 @@ target_emulate_readcapacity(struct se_task *task)
         return 0;
 }
 
-static int
-target_emulate_readcapacity_16(struct se_task *task)
+int target_emulate_readcapacity_16(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         struct se_device *dev = cmd->se_dev;
@@ -939,8 +937,7 @@ target_modesense_dpofua(unsigned char *buf, int type)
         }
 }
 
-static int
-target_emulate_modesense(struct se_task *task)
+int target_emulate_modesense(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         struct se_device *dev = cmd->se_dev;
@@ -1019,8 +1016,7 @@ target_emulate_modesense(struct se_task *task)
         return 0;
 }
 
-static int
-target_emulate_request_sense(struct se_task *task)
+int target_emulate_request_sense(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         unsigned char *cdb = cmd->t_task_cdb;
@@ -1090,8 +1086,7 @@ end:
  * Used for TCM/IBLOCK and TCM/FILEIO for block/blk-lib.c level discard support.
  * Note this is not used for TCM/pSCSI passthrough
  */
-static int
-target_emulate_unmap(struct se_task *task)
+int target_emulate_unmap(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         struct se_device *dev = cmd->se_dev;
@@ -1150,8 +1145,7 @@ err:
  * Used for TCM/IBLOCK and TCM/FILEIO for block/blk-lib.c level discard support.
  * Note this is not used for TCM/pSCSI passthrough
  */
-static int
-target_emulate_write_same(struct se_task *task)
+int target_emulate_write_same(struct se_task *task)
 {
         struct se_cmd *cmd = task->task_se_cmd;
         struct se_device *dev = cmd->se_dev;
@@ -1196,8 +1190,7 @@ target_emulate_write_same(struct se_task *task)
         return 0;
 }
 
-static int
-target_emulate_synchronize_cache(struct se_task *task)
+int target_emulate_synchronize_cache(struct se_task *task)
 {
         struct se_device *dev = task->task_se_cmd->se_dev;
 
@@ -1211,97 +1204,13 @@ target_emulate_synchronize_cache(struct se_task *task)
         return 0;
 }
 
-static int
-target_emulate_noop(struct se_task *task)
+int target_emulate_noop(struct se_task *task)
 {
         task->task_scsi_status = GOOD;
         transport_complete_task(task, 1);
         return 0;
 }
 
-int
-transport_emulate_control_cdb(struct se_task *task)
-{
-        struct se_cmd *cmd = task->task_se_cmd;
-        struct se_device *dev = cmd->se_dev;
-        unsigned short service_action;
-        int ret = 0;
-
-        switch (cmd->t_task_cdb[0]) {
-        case INQUIRY:
-                ret = target_emulate_inquiry(task);
-                break;
-        case READ_CAPACITY:
-                ret = target_emulate_readcapacity(task);
-                break;
-        case MODE_SENSE:
-                ret = target_emulate_modesense(task);
-                break;
-        case MODE_SENSE_10:
-                ret = target_emulate_modesense(task);
-                break;
-        case SERVICE_ACTION_IN:
-                switch (cmd->t_task_cdb[1] & 0x1f) {
-                case SAI_READ_CAPACITY_16:
-                        ret = target_emulate_readcapacity_16(task);
-                        break;
-                default:
-                        pr_err("Unsupported SA: 0x%02x\n",
-                                cmd->t_task_cdb[1] & 0x1f);
-                        return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
-                }
-                break;
-        case REQUEST_SENSE:
-                ret = target_emulate_request_sense(task);
-                break;
-        case UNMAP:
-                ret = target_emulate_unmap(task);
-                break;
-        case WRITE_SAME:
-                ret = target_emulate_write_same(task);
-                break;
-        case WRITE_SAME_16:
-                ret = target_emulate_write_same(task);
-                break;
-        case VARIABLE_LENGTH_CMD:
-                service_action =
-                        get_unaligned_be16(&cmd->t_task_cdb[8]);
-                switch (service_action) {
-                case WRITE_SAME_32:
-                        ret = target_emulate_write_same(task);
-                        break;
-                default:
-                        pr_err("Unsupported VARIABLE_LENGTH_CMD SA:"
-                                        " 0x%02x\n", service_action);
-                        break;
-                }
-                break;
-        case SYNCHRONIZE_CACHE:
-        case 0x91: /* SYNCHRONIZE_CACHE_16: */
-                ret = target_emulate_synchronize_cache(task);
-                break;
-        case ALLOW_MEDIUM_REMOVAL:
-        case ERASE:
-        case REZERO_UNIT:
-        case SEEK_10:
-        case SPACE:
-        case START_STOP:
-        case TEST_UNIT_READY:
-        case VERIFY:
-        case WRITE_FILEMARKS:
-                ret = target_emulate_noop(task);
-                break;
-        default:
-                pr_err("Unsupported SCSI Opcode: 0x%02x for %s\n",
-                        cmd->t_task_cdb[0], dev->transport->name);
-                return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
-        }
-
-        if (ret < 0)
-                return ret;
-        return PYX_TRANSPORT_SENT_TO_TRANSPORT;
-}
-
 /*
  * Write a CDB into @cdb that is based on the one the intiator sent us,
  * but updated to only cover the sectors that the current task handles.
diff --git a/drivers/target/target_core_cdb.h b/drivers/target/target_core_cdb.h
new file mode 100644
index 000000000000..ad6b1e393001
--- /dev/null
+++ b/drivers/target/target_core_cdb.h
@@ -0,0 +1,14 @@
+#ifndef TARGET_CORE_CDB_H
+#define TARGET_CORE_CDB_H
+
+int target_emulate_inquiry(struct se_task *task);
+int target_emulate_readcapacity(struct se_task *task);
+int target_emulate_readcapacity_16(struct se_task *task);
+int target_emulate_modesense(struct se_task *task);
+int target_emulate_request_sense(struct se_task *task);
+int target_emulate_unmap(struct se_task *task);
+int target_emulate_write_same(struct se_task *task);
+int target_emulate_synchronize_cache(struct se_task *task);
+int target_emulate_noop(struct se_task *task);
+
+#endif /* TARGET_CORE_CDB_H */
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 74015793c03a..f603b12485bd 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -52,6 +52,7 @@
 #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"
@@ -2155,31 +2156,11 @@ check_depth:
                 atomic_set(&cmd->t_transport_sent, 1);
 
         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-        /*
-         * The struct se_cmd->execute_task() 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->execute_task) {
-                error = cmd->execute_task(task);
-        } 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 (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);
@@ -2622,6 +2603,13 @@ 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);
@@ -2701,9 +2689,12 @@ 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.
                  */
@@ -2712,13 +2703,6 @@ 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);
@@ -2732,8 +2716,12 @@ 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.
@@ -2759,7 +2747,8 @@ 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"
@@ -2797,8 +2786,15 @@ 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:
@@ -2867,6 +2863,8 @@ 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];
@@ -2875,6 +2873,8 @@ 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:
@@ -2883,6 +2883,21 @@ 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:
@@ -2913,6 +2928,8 @@ 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];
@@ -2977,8 +2994,9 @@ static int transport_generic_cmd_sequencer(
                 size = transport_get_size(sectors, cdb, cmd);
                 cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
 
-                if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV)
+                if (passthrough)
                         break;
+
                 /*
                  * Check to ensure that LBA + Range does not exceed past end of
                  * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
@@ -2987,10 +3005,13 @@ 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);
@@ -3009,6 +3030,8 @@ 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);
@@ -3030,20 +3053,26 @@ 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;
@@ -3100,6 +3129,11 @@ 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)