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, 1 insertions, 1 deletions

diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 815e064028c9..69fb3cfd02d7 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -102,7 +102,7 @@ void	transport_init_se_cmd(struct se_cmd *, struct target_core_fabric_ops *,
                 struct se_session *, u32, int, int, unsigned char *);
 int     transport_lookup_cmd_lun(struct se_cmd *, u32);
 int     target_setup_cmd_from_cdb(struct se_cmd *, unsigned char *);
-void    target_submit_cmd(struct se_cmd *, struct se_session *, unsigned char *,
+int     target_submit_cmd(struct se_cmd *, struct se_session *, unsigned char *,
                 unsigned char *, u32, u32, int, int, int);
 int     target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
                 unsigned char *sense, u32 unpacked_lun,