2019-05-20 18:05:58

by Jason Yan

Subject: [PATCH v2] scsi: libsas: no need to join wide port again in sas_ex_discover_dev()

Since we are processing events synchronously now, the second call of
sas_ex_join_wide_port() in sas_ex_discover_dev() is not needed. There
will be no races with other works in disco workqueue. So remove the
second sas_ex_join_wide_port().

I did not change the return value of 'res' to error when discover failed
because we need to continue to discover other phys if one phy discover
failed. So let's keep that logic as before and just add a debug log to
detect the failure. And directly return if second fanout expander
attatched to the parent expander because it has nothing to do after the
phy is disabled.

Signed-off-by: Jason Yan <[email protected]>
---

v2: Directly return in the "second fanout expander" case and change the
log level to notice.

drivers/scsi/libsas/sas_expander.c | 26 ++++----------------------
1 file changed, 4 insertions(+), 22 deletions(-)

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 83f2fd70ce76..a148be23ca09 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -1104,7 +1104,7 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
SAS_ADDR(dev->sas_addr),
phy_id);
sas_ex_disable_phy(dev, phy_id);
- break;
+ return res;
} else
memcpy(dev->port->disc.fanout_sas_addr,
ex_phy->attached_sas_addr, SAS_ADDR_SIZE);
@@ -1116,27 +1116,9 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
break;
}

- if (child) {
- int i;
-
- for (i = 0; i < ex->num_phys; i++) {
- if (ex->ex_phy[i].phy_state == PHY_VACANT ||
- ex->ex_phy[i].phy_state == PHY_NOT_PRESENT)
- continue;
- /*
- * Due to races, the phy might not get added to the
- * wide port, so we add the phy to the wide port here.
- */
- if (SAS_ADDR(ex->ex_phy[i].attached_sas_addr) ==
- SAS_ADDR(child->sas_addr)) {
- ex->ex_phy[i].phy_state= PHY_DEVICE_DISCOVERED;
- if (sas_ex_join_wide_port(dev, i))
- pr_debug("Attaching ex phy%02d to wide port %016llx\n",
- i, SAS_ADDR(ex->ex_phy[i].attached_sas_addr));
- }
- }
- }
-
+ if (!child)
+ pr_notice("ex %016llx phy%02d failed to discover\n",
+ SAS_ADDR(dev->sas_addr), phy_id);
return res;
}

--
2.17.2

2019-05-20 18:06:23

by John Garry

Subject: Re: [PATCH v2] scsi: libsas: no need to join wide port again in sas_ex_discover_dev()

On 20/05/2019 15:06, Jason Yan wrote:
> Since we are processing events synchronously now, the second call of
> sas_ex_join_wide_port() in sas_ex_discover_dev() is not needed. There
> will be no races with other works in disco workqueue. So remove the
> second sas_ex_join_wide_port().
>
> I did not change the return value of 'res' to error when discover failed
> because we need to continue to discover other phys if one phy discover
> failed. So let's keep that logic as before and just add a debug log to
> detect the failure. And directly return if second fanout expander
> attatched to the parent expander because it has nothing to do after the
> phy is disabled.
>
> Signed-off-by: Jason Yan <[email protected]>
> ---

Reviewed-by: John Garry <[email protected]>

2019-05-30 02:15:13

by Martin K. Petersen

Subject: Re: [PATCH v2] scsi: libsas: no need to join wide port again in sas_ex_discover_dev()

Jason,

> Since we are processing events synchronously now, the second call of
> sas_ex_join_wide_port() in sas_ex_discover_dev() is not needed. There
> will be no races with other works in disco workqueue. So remove the
> second sas_ex_join_wide_port().

Applied to 5.3/scsi-queue, thanks!

--
Martin K. Petersen Oracle Linux Engineering