Re: [PATCH 2/3] ACPI / hotplug / PCI: Hotplug context objects for bridges and functions

From: Rafael J. Wysocki
Date: Mon Jul 08 2013 - 19:34:57 EST

Next message: Paul Bolle: "Re: [Xen-devel] [PATCH] xen: remove unused Kconfig parameter"
Previous message: Scott Wood: "Re: [linuxppc-dev] Unbinding device from a driver"
In reply to: Rafael J. Wysocki: "[PATCH 2/3] ACPI / hotplug / PCI: Hotplug context objects for bridges and functions"
Next in thread: Rafael J. Wysocki: "[PATCH 3/3] ACPI / hotplug / PCI: Unified notify handler for hotplug events"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On Monday, July 08, 2013 03:30:16 PM Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> When either a new hotplug brigde or a new hotplug function is added
> by the ACPI-based PCI hotplug (acpiphp) code, attach a context object
> to its ACPI handle to store hotplug-related information in it. To
> start with, put the handle's bridge and function pointers into that
> object. Count references to the context objects and drop them when
> they are not needed any more.
>
> First of all, this makes it possible to find out if the given bridge
> has been registered as a function already in a much more
> straightforward way and acpiphp_bridge_handle_to_function() can be
> dropped (Yay!).
>
> This also will allow some more simplifications to be made going
> forward.

Unfortunately, this one is buggy. ->

> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> drivers/pci/hotplug/acpiphp.h | 10 ++
> drivers/pci/hotplug/acpiphp_glue.c | 149 ++++++++++++++++++++++++++-----------
> 2 files changed, 116 insertions(+), 43 deletions(-)
>
> Index: linux-pm/drivers/pci/hotplug/acpiphp.h
> ===================================================================
> --- linux-pm.orig/drivers/pci/hotplug/acpiphp.h
> +++ linux-pm/drivers/pci/hotplug/acpiphp.h
> @@ -49,6 +49,7 @@
> #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg)
> #define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME , ## arg)
>
> +struct acpiphp_context;
> struct acpiphp_bridge;
> struct acpiphp_slot;
>
> @@ -77,6 +78,7 @@ struct acpiphp_bridge {
> struct kref ref;
> acpi_handle handle;
>
> + struct acpiphp_context *context;
> /* Ejectable PCI-to-PCI bridge (PCI bridge and PCI function) */
> struct acpiphp_func *func;
>
> @@ -119,6 +121,7 @@ struct acpiphp_slot {
> * typically 8 objects per slot (i.e. for each PCI function)
> */
> struct acpiphp_func {
> + struct acpiphp_context *context;
> struct acpiphp_slot *slot; /* parent */
>
> struct list_head sibling;
> @@ -129,6 +132,13 @@ struct acpiphp_func {
> u32 flags; /* see below */
> };
>
> +struct acpiphp_context {
> + struct kref kref;
> + acpi_handle handle;
> + struct acpiphp_func *func;
> + struct acpiphp_bridge *bridge;
> +};
> +
> /*
> * struct acpiphp_attention_info - device specific attention registration
> *
> Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c
> +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c
> @@ -79,6 +79,61 @@ is_pci_dock_device(acpi_handle handle, u
> }
> }
>
> +static void acpiphp_context_handler(acpi_handle handle, void *context)
> +{
> + /* Intentionally empty. */
> +}
> +
> +static struct acpiphp_context *acpiphp_init_context(acpi_handle handle)
> +{
> + struct acpiphp_context *context;
> + acpi_status status;
> +
> + context = kzalloc(sizeof(*context), GFP_KERNEL);
> + if (!context)
> + return NULL;
> +
> + context->handle = handle;
> + kref_init(&context->kref);
> + status = acpi_attach_data(handle, acpiphp_context_handler, context);
> + if (ACPI_FAILURE(status)) {
> + kfree(context);
> + return NULL;
> + }
> + return context;
> +}
> +
> +static struct acpiphp_context *acpiphp_get_context(acpi_handle handle)
> +{
> + struct acpiphp_context *context = NULL;
> + acpi_status status;
> + void *data;
> +
> + status = acpi_get_data(handle, acpiphp_context_handler, &data);
> + if (ACPI_SUCCESS(status)) {
> + context = data;
> + kref_get(&context->kref);
> + } else if (status == AE_NOT_FOUND) {
> + context = acpiphp_init_context(handle);
> + }
> + return context;
> +}
> +
> +static void acpiphp_release_context(struct kref *kref)
> +{
> + struct acpiphp_context *context;
> +
> + context = container_of(kref, struct acpiphp_context, kref);
> + WARN_ON(context->func || context->bridge);
> + acpi_detach_data(context->handle, acpiphp_context_handler);
> + kfree(context);
> +}
> +
> +static void acpiphp_put_context(struct acpiphp_context *context)
> +{
> + kref_put(&context->kref, acpiphp_release_context);
> +}
> +
> static inline void get_bridge(struct acpiphp_bridge *bridge)
> {
> kref_get(&bridge->ref);
> @@ -91,6 +146,7 @@ static inline void put_bridge(struct acp
>
> static void free_bridge(struct kref *kref)
> {
> + struct acpiphp_context *context;
> struct acpiphp_bridge *bridge;
> struct acpiphp_slot *slot, *next;
> struct acpiphp_func *func, *tmp;
> @@ -99,17 +155,24 @@ static void free_bridge(struct kref *kre
>
> list_for_each_entry_safe(slot, next, &bridge->slots, node) {
> list_for_each_entry_safe(func, tmp, &slot->funcs, sibling) {
> + context = func->context;
> + context->func = NULL;
> kfree(func);
> + acpiphp_put_context(context);
> }
> kfree(slot);
> }
>
> - /* Release reference acquired by acpiphp_bridge_handle_to_function() */
> + /* Release reference acquired by acpiphp_enumerate_slots(). */
> if ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func)
> put_bridge(bridge->func->slot->bridge);
> +
> put_device(&bridge->pci_bus->dev);
> pci_dev_put(bridge->pci_dev);
> + context = bridge->context;
> + context->bridge = NULL;
> kfree(bridge);
> + acpiphp_put_context(context);
> }
>
> /*
> @@ -195,10 +258,11 @@ static void acpiphp_dock_release(void *d
> }
>
> /* callback routine to register each ACPI PCI slot object */
> -static acpi_status
> -register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
> +static acpi_status register_slot(acpi_handle handle, u32 lvl, void *data,
> + void **rv)
> {
> - struct acpiphp_bridge *bridge = (struct acpiphp_bridge *)context;
> + struct acpiphp_bridge *bridge = (struct acpiphp_bridge *)data;
> + struct acpiphp_context *context;
> struct acpiphp_slot *slot;
> struct acpiphp_func *newfunc;
> acpi_handle tmp;
> @@ -229,8 +293,18 @@ register_slot(acpi_handle handle, u32 lv
> if (!newfunc)
> return AE_NO_MEMORY;
>
> + context = acpiphp_get_context(newfunc->handle);

-> Because newfunc->handle is still NULL here. Sorry about that.

I'll send an update shortly along with some more stuff on top.

> + if (!context) {
> + acpi_handle_err(newfunc->handle,
> + "Unable to get hotplug context\n");
> + kfree(newfunc);
> + return AE_NOT_EXIST;
> + }
> +
> newfunc->handle = handle;
> newfunc->function = function;
> + newfunc->context = context;
> + context->func = newfunc;
>
> if (ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
> newfunc->flags = FUNC_HAS_EJ0;
> @@ -268,8 +342,8 @@ register_slot(acpi_handle handle, u32 lv
> if (!found) {
> slot = kzalloc(sizeof(struct acpiphp_slot), GFP_KERNEL);
> if (!slot) {
> - kfree(newfunc);
> - return AE_NO_MEMORY;
> + status = AE_NO_MEMORY;
> + goto err_out;
> }
>
> slot->bridge = bridge;
> @@ -293,7 +367,9 @@ register_slot(acpi_handle handle, u32 lv
> else
> warn("acpiphp_register_hotplug_slot failed "
> "(err code = 0x%x)\n", retval);
> - goto err_exit;
> +
> + status = AE_OK;
> + goto err;
> }
> }
>
> @@ -339,15 +415,17 @@ register_slot(acpi_handle handle, u32 lv
>
> return AE_OK;
>
> - err_exit:
> + err:
> bridge->nr_slots--;
> mutex_lock(&bridge_mutex);
> list_del(&slot->node);
> mutex_unlock(&bridge_mutex);
> kfree(slot);
> + err_out:
> + context->func = NULL;
> kfree(newfunc);
> -
> - return AE_OK;
> + acpiphp_put_context(context);
> + return status;
> }
>
>
> @@ -362,32 +440,6 @@ static int detect_ejectable_slots(acpi_h
> return found;
> }
>
> -
> -/* find acpiphp_func from acpiphp_bridge */
> -static struct acpiphp_func *acpiphp_bridge_handle_to_function(acpi_handle handle)
> -{
> - struct acpiphp_bridge *bridge;
> - struct acpiphp_slot *slot;
> - struct acpiphp_func *func = NULL;
> -
> - mutex_lock(&bridge_mutex);
> - list_for_each_entry(bridge, &bridge_list, list) {
> - list_for_each_entry(slot, &bridge->slots, node) {
> - list_for_each_entry(func, &slot->funcs, sibling) {
> - if (func->handle == handle) {
> - get_bridge(func->slot->bridge);
> - mutex_unlock(&bridge_mutex);
> - return func;
> - }
> - }
> - }
> - }
> - mutex_unlock(&bridge_mutex);
> -
> - return NULL;
> -}
> -
> -
> static struct acpiphp_bridge *acpiphp_handle_to_bridge(acpi_handle handle)
> {
> struct acpiphp_bridge *bridge;
> @@ -1130,6 +1182,7 @@ static void handle_hotplug_event_func(ac
> */
> void acpiphp_enumerate_slots(struct pci_bus *bus)
> {
> + struct acpiphp_context *context;
> struct acpiphp_bridge *bridge;
> acpi_handle handle;
> acpi_status status;
> @@ -1141,9 +1194,16 @@ void acpiphp_enumerate_slots(struct pci_
> if (!handle || detect_ejectable_slots(handle) <= 0)
> return;
>
> + context = acpiphp_get_context(handle);
> + if (!context) {
> + acpi_handle_err(handle, "Unable to get hotplug context\n");
> + return;
> + }
> +
> bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
> if (bridge == NULL) {
> - err("out of memory\n");
> + acpi_handle_err(handle, "No memory for bridge object\n");
> + acpiphp_put_context(context);
> return;
> }
>
> @@ -1152,6 +1212,8 @@ void acpiphp_enumerate_slots(struct pci_
> bridge->handle = handle;
> bridge->pci_dev = pci_dev_get(bus->self);
> bridge->pci_bus = bus;
> + bridge->context = context;
> + context->bridge = bridge;
>
> /*
> * Grab a ref to the subordinate PCI bus in case the bus is
> @@ -1185,20 +1247,21 @@ void acpiphp_enumerate_slots(struct pci_
> "failed to register notify handler\n");
> goto err;
> }
> -
> status = acpi_get_handle(bridge->handle, "_EJ0", &handle);
> if (ACPI_FAILURE(status))
> return;
>
> dbg("found ejectable p2p bridge\n");
> bridge->flags |= BRIDGE_HAS_EJ0;
> - bridge->func = acpiphp_bridge_handle_to_function(bridge->handle);
> - if (bridge->func) {
> - status = acpi_remove_notify_handler(bridge->func->handle,
> - ACPI_SYSTEM_NOTIFY,
> + if (context->func) {
> + get_bridge(context->func->slot->bridge);
> + bridge->func = context->func;
> + handle = context->handle;
> + WARN_ON(bridge->handle != handle);
> + status = acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
> handle_hotplug_event_func);
> if (ACPI_FAILURE(status))
> - acpi_handle_err(bridge->func->handle,
> + acpi_handle_err(handle,
> "failed to remove notify handler\n");
> }
> return;
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: Paul Bolle: "Re: [Xen-devel] [PATCH] xen: remove unused Kconfig parameter"
Previous message: Scott Wood: "Re: [linuxppc-dev] Unbinding device from a driver"
In reply to: Rafael J. Wysocki: "[PATCH 2/3] ACPI / hotplug / PCI: Hotplug context objects for bridges and functions"
Next in thread: Rafael J. Wysocki: "[PATCH 3/3] ACPI / hotplug / PCI: Unified notify handler for hotplug events"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]