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    SubjectRe: [PATCH 03/12] libsas: Convert to host_lock less w/ interrupts disabled externally
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    On Mon, 2010-12-20 at 10:58 +0200, Boaz Harrosh wrote:
    > On 12/19/2010 11:21 PM, Nicholas A. Bellinger wrote:
    > > From: Nicholas Bellinger <nab@linux-iscsi.org>
    > >
    > > This patch converts the libsas queuecommand to run in host_lock less mode
    > > w/ the new IRQ_DISABLE_SCSI_QCMD() that disables interrupts while calling
    > > ->queuecommand() dispatch.
    > >
    > > Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
    > > ---
    > > drivers/scsi/libsas/sas_scsi_host.c | 12 ++----------
    > > 1 files changed, 2 insertions(+), 10 deletions(-)
    > >
    > > diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
    > > index 29251fa..011580f 100644
    > > --- a/drivers/scsi/libsas/sas_scsi_host.c
    > > +++ b/drivers/scsi/libsas/sas_scsi_host.c
    > > @@ -185,24 +185,17 @@ int sas_queue_up(struct sas_task *task)
    > > /**
    > > * sas_queuecommand -- Enqueue a command for processing
    > > * @parameters: See SCSI Core documentation
    > > - *
    > > - * Note: XXX: Remove the host unlock/lock pair when SCSI Core can
    > > - * call us without holding an IRQ spinlock...
    > > */
    > > -static int sas_queuecommand_lck(struct scsi_cmnd *cmd,
    > > +static int sas_queuecommand_irq_disable(struct scsi_cmnd *cmd,
    > > void (*scsi_done)(struct scsi_cmnd *))
    > > - __releases(host->host_lock)
    > > __acquires(dev->sata_dev.ap->lock)
    > > __releases(dev->sata_dev.ap->lock)
    > > - __acquires(host->host_lock)
    > > {
    > > int res = 0;
    > > struct domain_device *dev = cmd_to_domain_dev(cmd);
    > > struct Scsi_Host *host = cmd->device->host;
    > > struct sas_internal *i = to_sas_internal(host->transportt);
    > >
    > > - spin_unlock_irq(host->host_lock);
    > > -
    > > {
    > > struct sas_ha_struct *sas_ha = dev->port->ha;
    > > struct sas_task *task;
    > > @@ -250,11 +243,10 @@ static int sas_queuecommand_lck(struct scsi_cmnd *cmd,
    > > }
    > > }
    > > out:
    > > - spin_lock_irq(host->host_lock);
    > > return res;
    > > }
    > >
    > > -DEF_SCSI_QCMD(sas_queuecommand)
    > > +IRQ_DISABLE_SCSI_QCMD(sas_queuecommand)
    > >
    >
    > I hate this new macro. It is so simple by now. And anyway you are
    > doing them one by one and auditing the code. Please completely drop
    > this macro and open code it. There is no "safety" argument to this
    > ugliness, any more.
    >
    > (Completely drop the [PATCH 02/12] scsi: Add IRQ_DISABLE_SCSI_QCMD wrapper
    > patch and redo the users)
    >

    Hi Boaz,

    I am happy to open code the handful of remaining LLDs that need proper
    conversion for lock_less-LLDs-for-38-v4 and drop patch #2 now that we
    have isolated the first round of host_lock-less LLD conversions.

    Best Regards,

    --nab




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