linux/drivers/pci/hotplug/TODO
Vihas Mak e1a6333e7f PCI: ibmphp: Remove commented-out functions
The functions get_max_adapter_speed() and get_bus_name() in ibmphp_core.c
are commented-out and the fields .get_max_adapter_speed and
.get_bus_name_status are removed from struct hotplug_slot_ops in
pci_hotplug.h. Remove the commented-out functions.

Link: https://lore.kernel.org/r/20211209213618.20522-1-makvihas@gmail.com
Signed-off-by: Vihas Mak <makvihas@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2021-12-10 09:55:47 -06:00

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Contributions are solicited in particular to remedy the following issues:
cpcihp:
* There are no implementations of the ->hardware_test, ->get_power and
->set_power callbacks in struct cpci_hp_controller_ops. Why were they
introduced? Can they be removed from the struct?
cpqphp:
* The driver spawns a kthread cpqhp_event_thread() which is woken by the
hardirq handler cpqhp_ctrl_intr(). Convert this to threaded IRQ handling.
The kthread is also woken from the timer pushbutton_helper_thread(),
convert it to call irq_wake_thread(). Use pciehp as a template.
* A large portion of cpqphp_ctrl.c and cpqphp_pci.c concerns resource
management. Doesn't this duplicate functionality in the core?
ibmphp:
* Implementations of hotplug_slot_ops callbacks such as get_adapter_present()
in ibmphp_core.c create a copy of the struct slot on the stack, then perform
the actual operation on that copy. Determine if this overhead is necessary,
delete it if not. The functions also perform a NULL pointer check on the
struct hotplug_slot, this seems superfluous.
* Several functions access the pci_slot member in struct hotplug_slot even
though pci_hotplug.h declares it private. See get_max_bus_speed() for an
example. Either the pci_slot member should no longer be declared private
or ibmphp should store a pointer to its bus in struct slot. Probably the
former.
* ibmphp_init_devno() takes a struct slot **, it could instead take a
struct slot *.
* The return value of pci_hp_register() is not checked.
* The various slot data structures are difficult to follow and need to be
simplified. A lot of functions are too large and too complex, they need
to be broken up into smaller, manageable pieces. Negative examples are
ebda_rsrc_controller() and configure_bridge().
* A large portion of ibmphp_res.c and ibmphp_pci.c concerns resource
management. Doesn't this duplicate functionality in the core?
sgi_hotplug:
* Several functions access the pci_slot member in struct hotplug_slot even
though pci_hotplug.h declares it private. See sn_hp_destroy() for an
example. Either the pci_slot member should no longer be declared private
or sgi_hotplug should store a pointer to it in struct slot. Probably the
former.
shpchp:
* There is only a single implementation of struct hpc_ops. Can the struct be
removed and its functions invoked directly? This has already been done in
pciehp with commit 82a9e79ef132 ("PCI: pciehp: remove hpc_ops"). Clarify
if there was a specific reason not to apply the same change to shpchp.
* The ->get_mode1_ECC_cap callback in shpchp_hpc_ops is never invoked.
Why was it introduced? Can it be removed?
* The hardirq handler shpc_isr() queues events on a workqueue. It can be
simplified by converting it to threaded IRQ handling. Use pciehp as a
template.