Re: [PATCH v2 3/7] scsi: libsas: optimize the debug print of the revalidate process

From: John Garry
Date: Thu Jan 31 2019 - 05:25:36 EST

On 31/01/2019 01:31, Jason Yan wrote:


On 2019/1/31 0:41, John Garry wrote:
On 30/01/2019 08:24, Jason Yan wrote:
sas_rediscover() returns error code if discover failed for a expander
phy. And sas_ex_revalidate_domain() only returns the last phy's error
code. So when sas_revalidate_domain() prints the return value of the
discover process, we do not know if the revalidation for every phy is
successful or not. We just know the last bcast phy revalidation
succeeded or not.

No need to return a error code for sas_ex_revalidate_domain() and
sas_rediscover(), and just print the debug log for each bcast phy
directly
in sas_rediscover().

do we want to know about every PHY, or just the PHY where res != 0?


Here I mean every PHY that raises bcast.


This may be better added at the sas_rediscover() callsite. And do you feel adding this for every bcast phy is useful, or just those whose rediscover error'ed?




I don't see any optimisation here. Maybe an improvement.


Thanks, I will change the wording.


Signed-off-by: Jason Yan <yanaijie@xxxxxxxxxx>
CC: John Garry <john.garry@xxxxxxxxxx>
CC: Johannes Thumshirn <jthumshirn@xxxxxxx>
CC: Ewan Milne <emilne@xxxxxxxxxx>
CC: Christoph Hellwig <hch@xxxxxx>
CC: Tomas Henzl <thenzl@xxxxxxxxxx>
CC: Dan Williams <dan.j.williams@xxxxxxxxx>
CC: Hannes Reinecke <hare@xxxxxxxx>
---
drivers/scsi/libsas/sas_discover.c | 7 +++----
drivers/scsi/libsas/sas_expander.c | 11 ++++++-----
include/scsi/libsas.h | 2 +-
3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/libsas/sas_discover.c
b/drivers/scsi/libsas/sas_discover.c
index 726ada9b8c79..ffc571a12916 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -500,7 +500,6 @@ static void sas_discover_domain(struct work_struct
*work)

static void sas_revalidate_domain(struct work_struct *work)
{
- int res = 0;
struct sas_discovery_event *ev = to_sas_discovery_event(work);
struct asd_sas_port *port = ev->port;
struct sas_ha_struct *ha = port->ha;
@@ -521,10 +520,10 @@ static void sas_revalidate_domain(struct
work_struct *work)

if (ddev && (ddev->dev_type == SAS_FANOUT_EXPANDER_DEVICE ||
ddev->dev_type == SAS_EDGE_EXPANDER_DEVICE))
- res = sas_ex_revalidate_domain(ddev);
+ sas_ex_revalidate_domain(ddev);

- pr_debug("done REVALIDATING DOMAIN on port %d, pid:%d, res 0x%x\n",
- port->id, task_pid_nr(current), res);
+ pr_debug("done REVALIDATING DOMAIN on port %d, pid:%d\n",
+ port->id, task_pid_nr(current));
out:
mutex_unlock(&ha->disco_mutex);

diff --git a/drivers/scsi/libsas/sas_expander.c
b/drivers/scsi/libsas/sas_expander.c
index 7b0e6dcef6e6..5cd720f93f96 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -2062,7 +2062,7 @@ static int sas_rediscover_dev(struct
domain_device *dev, int phy_id, bool last)
* first phy,for other phys in this port, we add it to the port to
* forming the wide-port.
*/
-static int sas_rediscover(struct domain_device *dev, const int phy_id)
+static void sas_rediscover(struct domain_device *dev, const int phy_id)
{
struct expander_device *ex = &dev->ex_dev;
struct ex_phy *changed_phy = &ex->ex_phy[phy_id];
@@ -2090,7 +2090,9 @@ static int sas_rediscover(struct domain_device
*dev, const int phy_id)
res = sas_rediscover_dev(dev, phy_id, last);
} else
res = sas_discover_new(dev, phy_id);
- return res;
+
+ pr_debug("ex %016llx phy%d discover returned 0x%x\n",

Hmmm.. this is not just discover, but also rediscover


Yes, will fix.

+ SAS_ADDR(dev->sas_addr), phy_id, res);
}

/**
@@ -2102,7 +2104,7 @@ static int sas_rediscover(struct domain_device
*dev, const int phy_id)
* Discover process only interrogates devices in order to discover the
* domain.
*/
-int sas_ex_revalidate_domain(struct domain_device *port_dev)
+void sas_ex_revalidate_domain(struct domain_device *port_dev)
{
int res;
struct domain_device *dev = NULL;
@@ -2117,11 +2119,10 @@ int sas_ex_revalidate_domain(struct
domain_device *port_dev)
res = sas_find_bcast_phy(dev, &phy_id, i, true);

this was missed

Yes, the return value of sas_find_bcast_phy() is actually unused, and
inside the function debug info has been printed. So we can directly
make it a void function.

ok, but how about add a comment like:

-if (phy_id == -1)
+if (phy_id == -1) /* no remaining broadcast phy found */



if (phy_id == -1)
break;
- res = sas_rediscover(dev, phy_id);
+ sas_rediscover(dev, phy_id);
i = phy_id + 1;
} while (i < ex->num_phys);
}
- return res;
}

void sas_smp_handler(struct bsg_job *job, struct Scsi_Host *shost,
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 420156cea3ee..e557bcb0c266 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -692,7 +692,7 @@ int sas_discover_root_expander(struct
domain_device *);

void sas_init_ex_attr(void);

-int sas_ex_revalidate_domain(struct domain_device *);
+void sas_ex_revalidate_domain(struct domain_device *);

void sas_unregister_domain_devices(struct asd_sas_port *port, int
gone);
void sas_init_disc(struct sas_discovery *disc, struct asd_sas_port *);




.



.