Hi John,
On 2023/11/28 3:28, John Garry wrote:
On 24/11/2023 02:27, yangxingui wrote:
We already do this in sas_ex_join_wide_port(), right?
No, If the addr of ex_phy matches dev->parent, sas_ex_join_wide_port()
will not be called, but sas_add_parent_port() will be called as follows:
static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
{
struct expander_device *ex = &dev->ex_dev;
struct ex_phy *ex_phy = &ex->ex_phy[phy_id];
struct domain_device *child = NULL;
int res = 0;
<...>
/* Parent and domain coherency */
if (!dev->parent && sas_phy_match_port_addr(dev->port,
ex_phy)) {
sas_add_parent_port(dev, phy_id);
return 0;
}
if (dev->parent && sas_phy_match_dev_addr(dev->parent,
ex_phy)) {
sas_add_parent_port(dev, phy_id);
if (ex_phy->routing_attr == TABLE_ROUTING)
sas_configure_phy(dev, phy_id,
dev->port->sas_addr, 1);
return 0;
}
<...>
}
I am not saying that what we do now does not have a problem - I am
just trying to understand what currently happens
ok, because ex_phy->port is not set when calling
sas_add_parent_port(), when deleting phy from the parent wide port, it
is not removed from the phy_list of the parent wide port as follows:
static void sas_unregister_devs_sas_addr(struct domain_device *parent,
int phy_id, bool last)
{
<...>
// Since ex_phy->port is not set, this branch will not be enter
But then how does this ever work? It is because we follow path
sas_rediscover_dev() -> sas_discover_new() -> sas_ex_discover_devices()
-> sas_ex_discover_dev() -> sas_add_parent_port(), and not
sas_rediscover_dev() -> sas_discover_new() -> sas_ex_join_wide_port()?
If so, is that because ephy->sas_attached_phy == 0 in sas_discover_new()
-> sas_ex_join_wide_port() and it fails?
BTW, about something mentioned earlier - adding the phy19 with SAS_ADDR
Yes,
For phy19, when the phy is attached and added to the parent wide port,
the path is:
sas_rediscover()
->sas_discover_new()
->sas_ex_discover_devices()
->sas_ex_discover_dev()
-> sas_add_parent_port().
And the path called when it is removed from parent wide port is:
sas_rediscover()
->sas_unregister_devs_sas_addr() // The sas address of phy19 becomes 0.
Since ex_phy->port is NULL, phy19 is not removed from the parent wide
port's phy_list.
For phy0, it is connected to a new sata device.
sas_rediscover()
->sas_discover_new()->sas_ex_phy_discover()
->sas_ex_phy_discover_helper()
->sas_set_ex_phy() // The device type is stp. Since the linkrate
is 5 and less than 1.5G, sas_address is set to 0.
->sas_ex_discover_devices()
->sas_ex_discover_dev()
->sas_ex_discover_end_dev()
->sas_port_alloc() // Create port-7:7:0
->sas_ex_get_linkrate()
->sas_port_add_phy() // Try adding phy19 to port->7:7:0,
triggering BUG()
Thanks,
Xingui
.
