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Date: Thu, 18 Jul 2013 21:04:11 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Yinghai Lu <yinghai@...nel.org>
Cc: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
LKML <linux-kernel@...r.kernel.org>,
Linux PCI <linux-pci@...r.kernel.org>,
Jiang Liu <liuj97@...il.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH 4/30] ACPI / hotplug / PCI: Hotplug context objects for bridges and functions
On Wednesday, July 17, 2013 07:00:33 PM Yinghai Lu wrote:
> On Wed, Jul 17, 2013 at 4:17 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > When either a new hotplug bridge 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.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> > drivers/pci/hotplug/acpiphp.h | 10 ++
> > drivers/pci/hotplug/acpiphp_glue.c | 179 ++++++++++++++++++++++++++++---------
> > 2 files changed, 146 insertions(+), 43 deletions(-)
>
> no, more lines are added.
Well, that's what 'quilt refresh --diffstat' tells me, quite consistently.
Have you actually counted them?
> > 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;
> > @@ -128,6 +131,13 @@ struct acpiphp_func {
> > u32 flags; /* see below */
> > };
> >
> > +struct acpiphp_context {
> > + acpi_handle handle;
> > + struct acpiphp_func *func;
> > + struct acpiphp_bridge *bridge;
> > + unsigned int refcount;
> > +};
> > +
> > /*
> > * 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
> > @@ -55,6 +55,7 @@
> >
> > static LIST_HEAD(bridge_list);
> > static DEFINE_MUTEX(bridge_mutex);
> > +static DEFINE_MUTEX(acpiphp_context_lock);
> >
> > #define MY_NAME "acpiphp_glue"
> >
> > @@ -79,6 +80,74 @@ is_pci_dock_device(acpi_handle handle, u
> > }
> > }
> >
> > +static void acpiphp_context_handler(acpi_handle handle, void *context)
> > +{
> > + /* Intentionally empty. */
> > +}
> > +
> > +/**
> > + * acpiphp_init_context - Create hotplug context and grab a reference to it.
> > + * @handle: ACPI object handle to create the context for.
> > + *
> > + * Call under acpiphp_context_lock.
> > + */
> > +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;
> > + context->refcount = 1;
> > + status = acpi_attach_data(handle, acpiphp_context_handler, context);
> > + if (ACPI_FAILURE(status)) {
> > + kfree(context);
> > + return NULL;
> > + }
> > + return context;
> > +}
> > +
> > +/**
> > + * acpiphp_get_context - Get hotplug context and grab a reference to it.
> > + * @handle: ACPI object handle to get the context for.
> > + *
> > + * Call under acpiphp_context_lock.
> > + */
> > +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;
> > + context->refcount++;
> > + }
> > + return context;
> > +}
> > +
> > +/**
> > + * acpiphp_put_context - Drop a reference to ACPI hotplug context.
> > + * @handle: ACPI object handle to put the context for.
> > + *
> > + * The context object is removed if there are no more references to it.
> > + *
> > + * Call under acpiphp_context_lock.
> > + */
> > +static void acpiphp_put_context(struct acpiphp_context *context)
> > +{
> > + if (--context->refcount)
> > + return;
> > +
> > + WARN_ON(context->func || context->bridge);
> > + acpi_detach_data(context->handle, acpiphp_context_handler);
> > + kfree(context);
> > +}
> > +
> > static inline void get_bridge(struct acpiphp_bridge *bridge)
> > {
> > kref_get(&bridge->ref);
> > @@ -91,25 +160,37 @@ 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;
> >
> > + mutex_lock(&acpiphp_context_lock);
> > +
> > bridge = container_of(kref, struct acpiphp_bridge, ref);
> >
> > 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;
> > + acpiphp_put_context(context);
> > kfree(func);
> > }
> > kfree(slot);
> > }
> >
> > - /* Release reference acquired by acpiphp_bridge_handle_to_function() */
> > + /* Release the 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;
> > + acpiphp_put_context(context);
> > kfree(bridge);
> > +
> > + mutex_unlock(&acpiphp_context_lock);
> > }
> >
> > /*
> > @@ -194,10 +275,11 @@ 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 = data;
> > + struct acpiphp_context *context;
> > struct acpiphp_slot *slot;
> > struct acpiphp_func *newfunc;
> > acpi_status status = AE_OK;
> > @@ -230,6 +312,18 @@ register_slot(acpi_handle handle, u32 lv
> > newfunc->handle = handle;
> > newfunc->function = function;
> >
> > + mutex_lock(&acpiphp_context_lock);
> > + context = acpiphp_init_context(handle);
> > + if (!context) {
> > + mutex_unlock(&acpiphp_context_lock);
> > + acpi_handle_err(handle, "No hotplug context\n");
> > + kfree(newfunc);
> > + return AE_NOT_EXIST;
> > + }
> > + newfunc->context = context;
> > + context->func = newfunc;
> > + mutex_unlock(&acpiphp_context_lock);
> > +
> > if (acpi_has_method(handle, "_EJ0"))
> > newfunc->flags = FUNC_HAS_EJ0;
> >
> > @@ -266,8 +360,8 @@ 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;
> > @@ -291,7 +385,9 @@ 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;
> > }
> > }
> >
> > @@ -329,15 +425,20 @@ 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);
> > - kfree(newfunc);
> >
> > - return AE_OK;
> > + err_out:
> > + mutex_lock(&acpiphp_context_lock);
> > + context->func = NULL;
> > + acpiphp_put_context(context);
> > + mutex_unlock(&acpiphp_context_lock);
> > + kfree(newfunc);
> > + return status;
> > }
> >
> >
> > @@ -352,32 +453,6 @@ 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;
> > @@ -1108,6 +1183,7 @@ 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;
> > @@ -1120,8 +1196,8 @@ void acpiphp_enumerate_slots(struct pci_
> > return;
> >
> > bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
> > - if (bridge == NULL) {
> > - err("out of memory\n");
> > + if (!bridge) {
> > + acpi_handle_err(handle, "No memory for bridge object\n");
> > return;
> > }
> >
>
> can you put this change in another patch?
Yes, I can, but is it worth it?
> > @@ -1131,6 +1207,21 @@ void acpiphp_enumerate_slots(struct pci_
> > bridge->pci_dev = pci_dev_get(bus->self);
> > bridge->pci_bus = bus;
> >
> > + mutex_lock(&acpiphp_context_lock);
> > + context = acpiphp_get_context(handle);
> > + if (!context) {
> > + context = acpiphp_init_context(handle);
> > + if (!context) {
> > + mutex_unlock(&acpiphp_context_lock);
> > + acpi_handle_err(handle, "No hotplug context\n");
> > + kfree(bridge);
> > + return;
> > + }
> > + }
> > + bridge->context = context;
> > + context->bridge = bridge;
> > + mutex_unlock(&acpiphp_context_lock);
> > +
> > /*
> > * Grab a ref to the subordinate PCI bus in case the bus is
> > * removed via PCI core logical hotplug. The ref pins the bus
> > @@ -1169,13 +1260,15 @@ void acpiphp_enumerate_slots(struct pci_
> >
> > 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;
> >
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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