Messages in this thread | | | Date | Tue, 28 Nov 2023 11:45:55 +0800 | Subject | Re: [PATCH v4] scsi: libsas: Fix the failure of adding phy with zero-address to port | From | yangxingui <> |
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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 .
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