RE: [PATCH 07/12] qla2xxx: Convert to host_lock less w/ interruptsdisabled externally

[Nicholas A. Bellinger]

On Mon, 2010-12-20 at 16:37 -0800, Madhu Iyengar wrote:
> All,
> 
> We had (internally @ QLogic) come up with a couple of patches (attached).
> 
> Patch 1: Similar to the patch from NAB and from Mathew Wilcox
> Patch 2: A bit more changes with the host_lost within the qla2xxx driver.
> 
> The above 2 patches have gone through some testing as well, so far so good. Please take a look and let us know.
> 

Hi Madhu,

Thank you for your followup.  I think both of these patches look OK, so
please feel free to add my:

Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>

Also let me know if you prefer these to be carried for the next series
in lio-core-2.6.git/lock_less-LLDs-for-38-v4, or if you would rather
these be picked up by James directly.

Best Regards,

--nab



> Cheers,
> Madhu
> 
> -----Original Message-----
> From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi-owner@xxxxxxxxxxxxxxx] On Behalf Of Nicholas A. Bellinger
> Sent: Monday, December 20, 2010 1:24 AM
> To: Matthew Wilcox
> Cc: linux-scsi; linux-kernel; James Bottomley; Jeff Garzik; Christoph Hellwig; FUJITA Tomonori; Hannes Reinecke; Mike Christie; Mike Anderson; Tejun Heo; Vasu Dev; Tim Chen; Andi Kleen; Ravi Anand; Andrew Vasquez; Joe Eykholt; James Smart; Douglas Gilbert; adam radford; Kashyap Desai; MPTFusionLinux
> Subject: Re: [PATCH 07/12] qla2xxx: Convert to host_lock less w/ interrupts disabled externally
> 
> On Sun, 2010-12-19 at 16:11 -0700, Matthew Wilcox wrote:
> > On Sun, Dec 19, 2010 at 01:22:02PM -0800, Nicholas A. Bellinger wrote:
> > > This patch converts qla2xxx to run in host_lock less mode with the new
> > > IRQ_DISABLE_SCSI_QCMD() that disables interrupts while calling ->queuecommand()
> > > dispatch.  It also drops the legacy host_lock unlock optimization.
> > 
> > I'm not sure this is the right direction to go.  Now that Jeff's done
> > the pushdown and put in the compatibility macros, I don't think it makes
> > sense to do another partial transition on each driver.  Much better to
> > take our time, analyse each driver thoroughly, and kill the DEF_SCSI_QCMD
> > in each driver without introducing IRQ_DISABLE_SCSI_QCMD.
> > 
> > In particular for this driver, it explicitly re-enables interrupts,
> > so it's pretty easy to do a full conversion.  Compile-tested only.
> > 
> > Convert qla2xxx driver to run without the shost lock
> > 
> > Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> 
> Ok, this patch is functioning with LTP disktest I/O using .37-rc6
> initiator side lock_less operation.
> 
> This has been added as an incremental patch for lock_less-LLDs-for-38-v3
> here:
> 
> commit 355798dc3d97a0f07b14d1f3891ecca1802c9094
> Author: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> Date:   Mon Dec 20 01:24:12 2010 -0800
> 
>     qla2xxx: Convert qla2xxx driver to run without the shost lock
>     
>     This patch converts qla2xxx LLD code to run in fully lock-less mode
>     and removes IRQ_DISABLE_SCSI_QCMD usage.  This also includes a handful
>     of cleanups for cmd->scsi_done assignment removal from qla2x00_get_new_sp()
>     and renames one goto of the exception patch with the '_lock' suffix in
>     qla2xxx_queuecommand().
>     
>     So far this patch has been lightly tested with basic I/O functionality on
>     bare-metal x86_64 .37-rc6 using ISP-2532 8 Gb/sec HW.
>     
>     Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
>     Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
> 
> Thanks!
> 
> --nab
> 
> > 
> > diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
> > index 2c0876c..b44d986 100644
> > --- a/drivers/scsi/qla2xxx/qla_os.c
> > +++ b/drivers/scsi/qla2xxx/qla_os.c
> > @@ -513,7 +513,7 @@ qla24xx_fw_version_str(struct scsi_qla_host *vha, char *str)
> >  
> >  static inline srb_t *
> >  qla2x00_get_new_sp(scsi_qla_host_t *vha, fc_port_t *fcport,
> > -    struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
> > +    struct scsi_cmnd *cmd)
> >  {
> >  	srb_t *sp;
> >  	struct qla_hw_data *ha = vha->hw;
> > @@ -527,16 +527,15 @@ qla2x00_get_new_sp(scsi_qla_host_t *vha, fc_port_t *fcport,
> >  	sp->cmd = cmd;
> >  	sp->flags = 0;
> >  	CMD_SP(cmd) = (void *)sp;
> > -	cmd->scsi_done = done;
> >  	sp->ctx = NULL;
> >  
> >  	return sp;
> >  }
> >  
> >  static int
> > -qla2xxx_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
> > +qla2xxx_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
> >  {
> > -	scsi_qla_host_t *vha = shost_priv(cmd->device->host);
> > +	scsi_qla_host_t *vha = shost_priv(shost);
> >  	fc_port_t *fcport = (struct fc_port *) cmd->device->hostdata;
> >  	struct fc_rport *rport = starget_to_rport(scsi_target(cmd->device));
> >  	struct qla_hw_data *ha = vha->hw;
> > @@ -544,7 +543,6 @@ qla2xxx_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)
> >  	srb_t *sp;
> >  	int rval;
> >  
> > -	spin_unlock_irq(vha->host->host_lock);
> >  	if (ha->flags.eeh_busy) {
> >  		if (ha->flags.pci_channel_io_perm_failure)
> >  			cmd->result = DID_NO_CONNECT << 16;
> > @@ -577,39 +575,32 @@ qla2xxx_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)
> >  		goto qc24_target_busy;
> >  	}
> >  
> > -	sp = qla2x00_get_new_sp(base_vha, fcport, cmd, done);
> > +	sp = qla2x00_get_new_sp(base_vha, fcport, cmd);
> >  	if (!sp)
> > -		goto qc24_host_busy_lock;
> > +		goto qc24_host_busy;
> >  
> >  	rval = ha->isp_ops->start_scsi(sp);
> >  	if (rval != QLA_SUCCESS)
> >  		goto qc24_host_busy_free_sp;
> >  
> > -	spin_lock_irq(vha->host->host_lock);
> > -
> >  	return 0;
> >  
> >  qc24_host_busy_free_sp:
> >  	qla2x00_sp_free_dma(sp);
> >  	mempool_free(sp, ha->srb_mempool);
> >  
> > -qc24_host_busy_lock:
> > -	spin_lock_irq(vha->host->host_lock);
> > +qc24_host_busy:
> >  	return SCSI_MLQUEUE_HOST_BUSY;
> >  
> >  qc24_target_busy:
> > -	spin_lock_irq(vha->host->host_lock);
> >  	return SCSI_MLQUEUE_TARGET_BUSY;
> >  
> >  qc24_fail_command:
> > -	spin_lock_irq(vha->host->host_lock);
> > -	done(cmd);
> > +	cmd->scsi_done(cmd);
> >  
> >  	return 0;
> >  }
> >  
> > -static DEF_SCSI_QCMD(qla2xxx_queuecommand)
> > -
> >  
> >  /*
> >   * qla2x00_eh_wait_on_command
> > 
> 
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