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

Nicholas A. Bellinger
2010-12-23T21:55:30Z

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@linux-iscsi.org>

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@vger.kernel.org [mailto:linux-scsi-owner@vger.kernel.org] 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@linux.intel.com>
>
> 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@linux-iscsi.org>
> 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@linux.intel.com>
> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
>
> 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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