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, 3 insertions, 21 deletions

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 3df1c9b8ae6b..cbf5e4513741 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -148,22 +148,8 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
 	 * Allocate the necessary tasks to complete the received CDB+data
 	 */
 	ret = transport_generic_allocate_tasks(se_cmd, sc->cmnd);
-	if (ret == -ENOMEM) {
-		/* Out of Resources */
-		return PYX_TRANSPORT_LU_COMM_FAILURE;
-	} else if (ret == -EINVAL) {
-		/*
-		 * Handle case for SAM_STAT_RESERVATION_CONFLICT
-		 */
-		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
-			return PYX_TRANSPORT_RESERVATION_CONFLICT;
-		/*
-		 * Otherwise, return SAM_STAT_CHECK_CONDITION and return
-		 * sense data.
-		 */
-		return PYX_TRANSPORT_USE_SENSE_REASON;
-	}
-
+	if (ret != 0)
+		return ret;
 	/*
 	 * For BIDI commands, pass in the extra READ buffer
 	 * to transport_generic_map_mem_to_cmd() below..
@@ -194,12 +180,8 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
 	}
 
 	/* Tell the core about our preallocated memory */
-	ret = transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),
+	return 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;
-
-	return 0;
 }
 
 /*