target: Address legacy PYX_TRANSPORT_* return code breakage

This patch removes legacy usage of PYX_TRANSPORT_* return codes in a number
of locations and addresses cases where transport_generic_request_failure()
was returning the incorrect sense upon CHECK_CONDITION status after the
v3.1 converson to use errno return codes.

This includes the conversion of transport_generic_request_failure() to
process cmd->scsi_sense_reason and handle extra TCM_RESERVATION_CONFLICT
before calling transport_send_check_condition_and_sense() to queue up
response status.  It also drops PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES legacy
usgae, and returns TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE w/ a response
for these cases.

transport_generic_allocate_tasks(), transport_generic_new_cmd(), backend
SCF_SCSI_DATA_SG_IO_CDB ->do_task(), and emulated ->execute_task() have
all been updated to set se_cmd->scsi_sense_reason and return errno codes
universally upon failure.  This includes cmd->scsi_sense_reason assignment
in target_core_alua.c, target_core_pr.c and target_core_cdb.c emulation code.

Finally it updates fabric modules to remove the legacy usage, and for
TFO->new_cmd_map() callers forwards return values outside of fabric code.
iscsi-target has also been updated to remove a handful of special cases
related to the cleanup and signaling QUEUE_FULL handling w/ ft_write_pending()

(v2: Drop extra SCF_SCSI_CDB_EXCEPTION check during failure from
     transport_generic_new_cmd, and re-add missing task->task_error_status
     assignment in transport_complete_task)

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

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c
index 683ba02b8247..8013a5a7bf64 100644
--- a/drivers/target/target_core_cdb.c
+++ b/drivers/target/target_core_cdb.c
@@ -703,6 +703,7 @@ int target_emulate_inquiry(struct se_task *task)
         if (cmd->data_length < 4) {
                 pr_err("SCSI Inquiry payload length: %u"
                         " too small for EVPD=1\n", cmd->data_length);
+                cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
                 return -EINVAL;
         }
 
@@ -719,6 +720,7 @@ int target_emulate_inquiry(struct se_task *task)
         }
 
         pr_err("Unknown VPD Code: 0x%02x\n", cdb[2]);
+        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
         ret = -EINVAL;
 
 out_unmap:
@@ -969,7 +971,8 @@ int target_emulate_modesense(struct se_task *task)
         default:
                 pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
                        cdb[2] & 0x3f, cdb[3]);
-                return PYX_TRANSPORT_UNKNOWN_MODE_PAGE;
+                cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
+                return -EINVAL;
         }
         offset += length;
 
@@ -1027,7 +1030,8 @@ int target_emulate_request_sense(struct se_task *task)
         if (cdb[1] & 0x01) {
                 pr_err("REQUEST_SENSE description emulation not"
                         " supported\n");
-                return PYX_TRANSPORT_INVALID_CDB_FIELD;
+                cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+                return -ENOSYS;
         }
 
         buf = transport_kmap_first_data_page(cmd);
@@ -1100,7 +1104,8 @@ int target_emulate_unmap(struct se_task *task)
         if (!dev->transport->do_discard) {
                 pr_err("UNMAP emulation not supported for: %s\n",
                                 dev->transport->name);
-                return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+                cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+                return -ENOSYS;
         }
 
         /* First UNMAP block descriptor starts at 8 byte offset */
@@ -1157,7 +1162,8 @@ int target_emulate_write_same(struct se_task *task)
         if (!dev->transport->do_discard) {
                 pr_err("WRITE_SAME emulation not supported"
                                 " for: %s\n", dev->transport->name);
-                return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+                cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+                return -ENOSYS;
         }
 
         if (cmd->t_task_cdb[0] == WRITE_SAME)
@@ -1193,11 +1199,13 @@ int target_emulate_write_same(struct se_task *task)
 int target_emulate_synchronize_cache(struct se_task *task)
 {
         struct se_device *dev = task->task_se_cmd->se_dev;
+        struct se_cmd *cmd = task->task_se_cmd;
 
         if (!dev->transport->do_sync_cache) {
                 pr_err("SYNCHRONIZE_CACHE emulation not supported"
                         " for: %s\n", dev->transport->name);
-                return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+                cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+                return -ENOSYS;
         }
 
         dev->transport->do_sync_cache(task);