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, 9 insertions, 5 deletions

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 7698efe29262..c670b8c2c994 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -554,12 +554,15 @@ static int iblock_do_task(struct se_task *task)
 	else {
 		pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 				" %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
-		return PYX_TRANSPORT_LU_COMM_FAILURE;
+		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		return -ENOSYS;
 	}
 
 	bio = iblock_get_bio(task, block_lba, sg_num);
-	if (!bio)
-		return PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
+	if (!bio) {
+		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		return -ENOMEM;
+	}
 
 	bio_list_init(&list);
 	bio_list_add(&list, bio);
@@ -588,12 +591,13 @@ static int iblock_do_task(struct se_task *task)
 		submit_bio(rw, bio);
 	blk_finish_plug(&plug);
 
-	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+	return 0;
 
 fail:
 	while ((bio = bio_list_pop(&list)))
 		bio_put(bio);
-	return PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
+	cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	return -ENOMEM;
 }
 
 static u32 iblock_get_device_rev(struct se_device *dev)