On Tue, 2016-01-12 at 16:20 +0100, Christoph Hellwig wrote:
> > It also introduces SCF_ACK_KREF to determine when
> > transport_cmd_finish_abort() needs to drop the second
> > extra reference, ahead of calling target_put_sess_cmd()
> > for the final kref_put(&se_cmd->cmd_kref).
>
> It would be really useful to have all drivers follow that
> ACK KREF model instead of needing to deal with driver
> differences everywhere..
>
tcm_fc, usb-gadget, sbp-target and xen-scsiback are whom
need to be converted.
It should be easy enough to do for v4.6 code.
> > Finally, move transport_put_cmd() release of SGL +
> > TMR + extended CDB memory into target_free_cmd_mem()
> > in order to avoid potential resource leaks in TMR
> > ABORT_TASK + LUN_RESET code-paths. Also update
> > target_release_cmd_kref() accordingly.
>
> Sounds like that should be a separate patch.
>
This should to stay with the original bug-fix for stable back-porting
purposes, and it's been kept together with the original for now.
It's time-consuming enough to back-port given the various upstream
changes recently.
> > +/*
> > + * Called with se_session->sess_cmd_lock held with irq disabled
> > + */
>
> Please enforce this in the code instead of the comments, e.g.
>
> assert_spin_locked(&se_session->sess_cmd_lock);
> WARN_ON_ONCE(!irqs_disabled());
>
Done.
> > +static bool __target_check_io_state(struct se_cmd *se_cmd)
> > +{
> > + struct se_session *sess = se_cmd->se_sess;
> > +
> > + if (!sess)
> > + return false;
>
> Given that you expect the session lock to be held this doesn't
> make sense.
>
Dropped.
> > + /*
> > + * Obtain cmd_kref and move to list for shutdown processing
> > + * if se_cmd->cmd_kref is still active, the command has not
> > + * already reached CMD_T_COMPLETE
> > + */
>
> This just explains what __target_check_io_state does, but no why.
> I'd suggest to remove the comment as it doesn't add any value.
How about the following for __target_check_io_state()..?
/*
* If command already reached CMD_T_COMPLETE state within
* target_complete_cmd(), this se_cmd has been passed to
* fabric driver and will not be aborted.
*
* Otherwise, obtain a local se_cmd->cmd_kref now for TMR
* ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
* long as se_cmd->cmd_kref is still active unless zero.
*/
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