Re: [PATCH] [RESEND] qla2xxx: fix potential deadlock onha->hardware_lock

[Arun Easi]

Hi Nick,

On Tue, 9 Oct 2012, 11:47am -0700, Nicholas A. Bellinger wrote:

> Hi Jiri, Andrew, Arun & Co,
--8<-- snipped --
> Also please have a look below for a few more related items I noticed
> while reviewing this patch..
>
> >  drivers/scsi/qla2xxx/qla_init.c |    5 +++--
> >  1 files changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
> > index 799a58b..48fca47 100644
> > --- a/drivers/scsi/qla2xxx/qla_init.c
> > +++ b/drivers/scsi/qla2xxx/qla_init.c
> > @@ -2080,6 +2080,7 @@ qla2x00_configure_hba(scsi_qla_host_t *vha)
> >      uint8_t       domain;
> >      char            connect_type[22];
> >      struct qla_hw_data *ha = vha->hw;
> > +    unsigned long flags;
> >
> >      /* Get host addresses. */
> >      rval = qla2x00_get_adapter_id(vha,
> > @@ -2154,9 +2155,9 @@ qla2x00_configure_hba(scsi_qla_host_t *vha)
> >      vha->d_id.b.area = area;
> >      vha->d_id.b.al_pa = al_pa;
> >
> > -    spin_lock(&ha->vport_slock);
> > +    spin_lock_irqsave(&ha->vport_slock, flags);
> >      qlt_update_vp_map(vha, SET_AL_PA);
> > -    spin_unlock(&ha->vport_slock);
> > +    spin_unlock_irqrestore(&ha->vport_slock, flags);
> >
> >      if (!vha->flags.init_done)
> >              ql_log(ql_log_info, vha, 0x2010,
>
> So while looking at other ->vport_slock + qlt_update_vp_map() usage, two
> more items caught my eye:
>
> In qla_mid.c:qla24xx_disable_vp() code:
>
>        ret = qla24xx_control_vp(vha, VCE_COMMAND_DISABLE_VPS_LOGO_ALL);
>        atomic_set(&vha->loop_state, LOOP_DOWN);
>        atomic_set(&vha->loop_down_timer, LOOP_DOWN_TIME);
>
>        /* Remove port id from vp target map */
>        qlt_update_vp_map(vha, RESET_AL_PA);
>
>        qla2x00_mark_vp_devices_dead(vha);
>        atomic_set(&vha->vp_state, VP_FAILED);
>
> AFAICT all callers of qlt_update_vp_map() into qla_target.c code should
> be holding ->vport_slock.  I'll send out a separate patch for this
> shortly.

Makes sense.

> And in qla_init.c:qla2x00_init_rings() code:
>
>        for (que = 0; que < ha->max_rsp_queues; que++) {
>                rsp = ha->rsp_q_map[que];
>                if (!rsp)
>                        continue;
>                /* Initialize response queue entries */
>                qla2x00_init_response_q_entries(rsp);
>        }
>
>        spin_lock(&ha->vport_slock);
>
>        spin_unlock(&ha->vport_slock);
>
>        ha->tgt.atio_ring_ptr = ha->tgt.atio_ring;
>        ha->tgt.atio_ring_index = 0;
>        /* Initialize ATIO queue entries */
>        qlt_init_atio_q_entries(vha);
>
> The usage of ->vport_slock seems to be now either unnecessary, or a
> result of some bad merge outside of qla2xxx target mode.
>
> Qlogic folks, can this (leftover..?) usage of ->vport_slock now be
> safety removed..?

Yes, this is a left over of code removal and can be safely removed. We
already have a patch queued internally for this.

--Arun

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