target: Allow for target_submit_cmd() returning errors

We want it to be possible for target_submit_cmd() to return errors up
to its fabric module callers.  For now just update the prototype to
return an int, and update all callers to handle non-zero return values
as an error.

This is immediately useful for tcm_qla2xxx to fix a long-standing active
I/O session shutdown race, but tcm_fc, usb-gadget, and sbp-target the
fabric maintainers need to check + ACK that handling a target_submit_cmd()
failure due to session shutdown does not introduce regressions

(nab: Respin against for-next after initial NACK + update docbook comment +
      fix double se_cmd init in exception path for usb-gadget)

Cc: Chad Dupuis <chad.dupuis@qlogic.com>
Cc: Arun Easi <arun.easi@qlogic.com>
Cc: Chris Boot <bootc@bootc.net>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 22 insertions, 14 deletions

diff --git a/drivers/usb/gadget/tcm_usb_gadget.c b/drivers/usb/gadget/tcm_usb_gadget.c
index 02ace18fca0b..5444866e13ef 100644
--- a/drivers/usb/gadget/tcm_usb_gadget.c
+++ b/drivers/usb/gadget/tcm_usb_gadget.c
@@ -1065,16 +1065,20 @@ static void usbg_cmd_work(struct work_struct *work)
                                 tv_nexus->tvn_se_sess->se_tpg->se_tpg_tfo,
                                 tv_nexus->tvn_se_sess, cmd->data_len, DMA_NONE,
                                 cmd->prio_attr, cmd->sense_iu.sense);
-
-                transport_send_check_condition_and_sense(se_cmd,
-                                TCM_UNSUPPORTED_SCSI_OPCODE, 1);
-                usbg_cleanup_cmd(cmd);
-                return;
+                goto out;
         }
 
-        target_submit_cmd(se_cmd, tv_nexus->tvn_se_sess,
+        if (target_submit_cmd(se_cmd, tv_nexus->tvn_se_sess,
                         cmd->cmd_buf, cmd->sense_iu.sense, cmd->unpacked_lun,
-                        0, cmd->prio_attr, dir, TARGET_SCF_UNKNOWN_SIZE);
+                        0, cmd->prio_attr, dir, TARGET_SCF_UNKNOWN_SIZE) < 0)
+                goto out;
+
+        return;
+
+out:
+        transport_send_check_condition_and_sense(se_cmd,
+                        TCM_UNSUPPORTED_SCSI_OPCODE, 1);
+        usbg_cleanup_cmd(cmd);
 }
 
 static int usbg_submit_command(struct f_uas *fu,
@@ -1177,16 +1181,20 @@ static void bot_cmd_work(struct work_struct *work)
                                 tv_nexus->tvn_se_sess->se_tpg->se_tpg_tfo,
                                 tv_nexus->tvn_se_sess, cmd->data_len, DMA_NONE,
                                 cmd->prio_attr, cmd->sense_iu.sense);
-
-                transport_send_check_condition_and_sense(se_cmd,
-                                TCM_UNSUPPORTED_SCSI_OPCODE, 1);
-                usbg_cleanup_cmd(cmd);
-                return;
+                goto out;
         }
 
-        target_submit_cmd(se_cmd, tv_nexus->tvn_se_sess,
+        if (target_submit_cmd(se_cmd, tv_nexus->tvn_se_sess,
                         cmd->cmd_buf, cmd->sense_iu.sense, cmd->unpacked_lun,
-                        cmd->data_len, cmd->prio_attr, dir, 0);
+                        cmd->data_len, cmd->prio_attr, dir, 0) < 0)
+                goto out;
+
+        return;
+
+out:
+        transport_send_check_condition_and_sense(se_cmd,
+                                TCM_UNSUPPORTED_SCSI_OPCODE, 1);
+        usbg_cleanup_cmd(cmd);
 }
 
 static int bot_submit_command(struct f_uas *fu,