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

Matthew Wilcox
2010-12-19T23:11:20Z

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>

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

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."