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, 5 insertions, 3 deletions

diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index 4ad58ac823e5..b9cb5006177e 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -543,9 +543,11 @@ static void ft_send_work(struct work_struct *work)
          * Use a single se_cmd->cmd_kref as we expect to release se_cmd
          * directly from ft_check_stop_free callback in response path.
          */
-        target_submit_cmd(&cmd->se_cmd, cmd->sess->se_sess, fcp->fc_cdb,
-                        &cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
-                        ntohl(fcp->fc_dl), task_attr, data_dir, 0);
+        if (target_submit_cmd(&cmd->se_cmd, cmd->sess->se_sess, fcp->fc_cdb,
+                              &cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
+                              ntohl(fcp->fc_dl), task_attr, data_dir, 0))
+                goto err;
+
         pr_debug("r_ctl %x alloc target_submit_cmd\n", fh->fh_r_ctl);
         return;