Patchwork ACPI / PCI: Initialize PCI root drivers after PCI bus enumeration

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Submitter Rafael J. Wysocki
Date Feb. 13, 2013, 12:16 a.m.
Message ID <1882094.fnYp8pBVVX@vostro.rjw.lan>
Download mbox | patch
Permalink /patch/220010/
State Not Applicable
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Rafael J. Wysocki - Feb. 13, 2013, 12:16 a.m.
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

After commit 1aeae82 (ACPI / PCI: avoid building pci_slot as module)
the pci_slot driver's .add() callback routine, acpi_pci_slot_add(),
is executed from within acpi_pci_root_add() before the PCI devices on
the bus are enumerated and that triggers the WARN_ON() in
kobject_get():

WARNING: at /scratch/rafael/work/test/include/linux/kref.h:42 kobject_get+0x33/0x40()
Hardware name: PORTEGE R500
Modules linked in:
Pid: 1, comm: swapper/0 Not tainted 3.8.0-rc7+ #160
Call Trace:
 [<ffffffff8103d38a>] warn_slowpath_common+0x7a/0xb0
 [<ffffffff8103d3d5>] warn_slowpath_null+0x15/0x20
 [<ffffffff812f99b3>] kobject_get+0x33/0x40
 [<ffffffff81452b82>] get_device+0x12/0x30
 [<ffffffff8138df7b>] register_slot+0x243/0x295
 [<ffffffff810a7b6d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
 [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
 [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
 [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
 [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
 [<ffffffff8138dcf5>] walk_p2p_bridge+0xf8/0x13b
 [<ffffffff8134d606>] ? acpi_os_signal_semaphore+0x76/0x87
 [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
 [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
 [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
 [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
 [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
 [<ffffffff81356071>] ? acpi_pci_root_add+0x3e7/0x49a
 [<ffffffff8138e07f>] acpi_pci_slot_add+0xb2/0x103
 [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
 [<ffffffff81356089>] acpi_pci_root_add+0x3ff/0x49a

which means that pci_bus->dev used in register_slot() has not been
registered yet at that point.

To fix this use the observation that before commit 1aeae82
acpi_pci_slot_add() was always run after pci_bus_add_devices()
and that happened to the acpiphp's .add() callback routine too.
Thus it is safe to reorder acpi_pci_root_add() to make the PCI root
drivers' .add() callbacks be run after pci_bus_add_devices(), so do
that.

This approach was previously proposed by Myron Stowe.

References: https://patchwork.kernel.org/patch/1848781/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

The commit mentioned in the changelog above is in linux-pm.git/linux-next.

Thanks,
Rafael

---
 drivers/acpi/pci_root.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)


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Yinghai Lu - Feb. 13, 2013, 1:54 a.m.
On Tue, Feb 12, 2013 at 4:16 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> After commit 1aeae82 (ACPI / PCI: avoid building pci_slot as module)
> the pci_slot driver's .add() callback routine, acpi_pci_slot_add(),
> is executed from within acpi_pci_root_add() before the PCI devices on
> the bus are enumerated and that triggers the WARN_ON() in
> kobject_get():
>
> WARNING: at /scratch/rafael/work/test/include/linux/kref.h:42 kobject_get+0x33/0x40()
> Hardware name: PORTEGE R500
> Modules linked in:
> Pid: 1, comm: swapper/0 Not tainted 3.8.0-rc7+ #160
> Call Trace:
>  [<ffffffff8103d38a>] warn_slowpath_common+0x7a/0xb0
>  [<ffffffff8103d3d5>] warn_slowpath_null+0x15/0x20
>  [<ffffffff812f99b3>] kobject_get+0x33/0x40
>  [<ffffffff81452b82>] get_device+0x12/0x30
>  [<ffffffff8138df7b>] register_slot+0x243/0x295
>  [<ffffffff810a7b6d>] ? trace_hardirqs_on+0xd/0x10
>  [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
>  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>  [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
>  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>  [<ffffffff8138dcf5>] walk_p2p_bridge+0xf8/0x13b
>  [<ffffffff8134d606>] ? acpi_os_signal_semaphore+0x76/0x87
>  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>  [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
>  [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
>  [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
>  [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
>  [<ffffffff81356071>] ? acpi_pci_root_add+0x3e7/0x49a
>  [<ffffffff8138e07f>] acpi_pci_slot_add+0xb2/0x103
>  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>  [<ffffffff81356089>] acpi_pci_root_add+0x3ff/0x49a
>
> which means that pci_bus->dev used in register_slot() has not been
> registered yet at that point.
>
> To fix this use the observation that before commit 1aeae82
> acpi_pci_slot_add() was always run after pci_bus_add_devices()
> and that happened to the acpiphp's .add() callback routine too.
> Thus it is safe to reorder acpi_pci_root_add() to make the PCI root
> drivers' .add() callbacks be run after pci_bus_add_devices(), so do
> that.
>
> This approach was previously proposed by Myron Stowe.
>
> References: https://patchwork.kernel.org/patch/1848781/
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> The commit mentioned in the changelog above is in linux-pm.git/linux-next.
>
> Thanks,
> Rafael
>
> ---
>  drivers/acpi/pci_root.c |   13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> Index: test/drivers/acpi/pci_root.c
> ===================================================================
> --- test.orig/drivers/acpi/pci_root.c
> +++ test/drivers/acpi/pci_root.c
> @@ -600,17 +600,20 @@ static int acpi_pci_root_add(struct acpi
>         if (system_state != SYSTEM_BOOTING)
>                 pci_assign_unassigned_bus_resources(root->bus);
>
> +       /* need to after hot-added ioapic is registered */
> +       if (system_state != SYSTEM_BOOTING)
> +               pci_enable_bridges(root->bus);
> +
> +       pci_bus_add_devices(root->bus);
> +
>         mutex_lock(&acpi_pci_root_lock);
> +
>         list_for_each_entry(driver, &acpi_pci_drivers, node)
>                 if (driver->add)
>                         driver->add(root);
> -       mutex_unlock(&acpi_pci_root_lock);
>
> -       /* need to after hot-added ioapic is registered */
> -       if (system_state != SYSTEM_BOOTING)
> -               pci_enable_bridges(root->bus);
> +       mutex_unlock(&acpi_pci_root_lock);
>
> -       pci_bus_add_devices(root->bus);
>         return 1;
>
>  out_del_root:
>

No, we don't need this after

| commit 4f535093cf8f6da8cfda7c36c2c1ecd2e9586ee4
|     PCI: Put pci_dev in device tree as early as possible

in pci/next.

So we can move that Jiang's patch from your tree to Bjorn's tree?

Thanks

Yinghai
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Rafael J. Wysocki - Feb. 13, 2013, 12:59 p.m.
On Tuesday, February 12, 2013 05:54:08 PM Yinghai Lu wrote:
> On Tue, Feb 12, 2013 at 4:16 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > After commit 1aeae82 (ACPI / PCI: avoid building pci_slot as module)
> > the pci_slot driver's .add() callback routine, acpi_pci_slot_add(),
> > is executed from within acpi_pci_root_add() before the PCI devices on
> > the bus are enumerated and that triggers the WARN_ON() in
> > kobject_get():
> >
> > WARNING: at /scratch/rafael/work/test/include/linux/kref.h:42 kobject_get+0x33/0x40()
> > Hardware name: PORTEGE R500
> > Modules linked in:
> > Pid: 1, comm: swapper/0 Not tainted 3.8.0-rc7+ #160
> > Call Trace:
> >  [<ffffffff8103d38a>] warn_slowpath_common+0x7a/0xb0
> >  [<ffffffff8103d3d5>] warn_slowpath_null+0x15/0x20
> >  [<ffffffff812f99b3>] kobject_get+0x33/0x40
> >  [<ffffffff81452b82>] get_device+0x12/0x30
> >  [<ffffffff8138df7b>] register_slot+0x243/0x295
> >  [<ffffffff810a7b6d>] ? trace_hardirqs_on+0xd/0x10
> >  [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
> >  [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
> >  [<ffffffff8138dcf5>] walk_p2p_bridge+0xf8/0x13b
> >  [<ffffffff8134d606>] ? acpi_os_signal_semaphore+0x76/0x87
> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
> >  [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
> >  [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
> >  [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
> >  [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
> >  [<ffffffff81356071>] ? acpi_pci_root_add+0x3e7/0x49a
> >  [<ffffffff8138e07f>] acpi_pci_slot_add+0xb2/0x103
> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
> >  [<ffffffff81356089>] acpi_pci_root_add+0x3ff/0x49a
> >
> > which means that pci_bus->dev used in register_slot() has not been
> > registered yet at that point.
> >
> > To fix this use the observation that before commit 1aeae82
> > acpi_pci_slot_add() was always run after pci_bus_add_devices()
> > and that happened to the acpiphp's .add() callback routine too.
> > Thus it is safe to reorder acpi_pci_root_add() to make the PCI root
> > drivers' .add() callbacks be run after pci_bus_add_devices(), so do
> > that.
> >
> > This approach was previously proposed by Myron Stowe.
> >
> > References: https://patchwork.kernel.org/patch/1848781/
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >
> > The commit mentioned in the changelog above is in linux-pm.git/linux-next.
> >
> > Thanks,
> > Rafael
> >
> > ---
> >  drivers/acpi/pci_root.c |   13 ++++++++-----
> >  1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > Index: test/drivers/acpi/pci_root.c
> > ===================================================================
> > --- test.orig/drivers/acpi/pci_root.c
> > +++ test/drivers/acpi/pci_root.c
> > @@ -600,17 +600,20 @@ static int acpi_pci_root_add(struct acpi
> >         if (system_state != SYSTEM_BOOTING)
> >                 pci_assign_unassigned_bus_resources(root->bus);
> >
> > +       /* need to after hot-added ioapic is registered */
> > +       if (system_state != SYSTEM_BOOTING)
> > +               pci_enable_bridges(root->bus);
> > +
> > +       pci_bus_add_devices(root->bus);
> > +
> >         mutex_lock(&acpi_pci_root_lock);
> > +
> >         list_for_each_entry(driver, &acpi_pci_drivers, node)
> >                 if (driver->add)
> >                         driver->add(root);
> > -       mutex_unlock(&acpi_pci_root_lock);
> >
> > -       /* need to after hot-added ioapic is registered */
> > -       if (system_state != SYSTEM_BOOTING)
> > -               pci_enable_bridges(root->bus);
> > +       mutex_unlock(&acpi_pci_root_lock);
> >
> > -       pci_bus_add_devices(root->bus);
> >         return 1;
> >
> >  out_del_root:
> >
> 
> No, we don't need this after
> 
> | commit 4f535093cf8f6da8cfda7c36c2c1ecd2e9586ee4
> |     PCI: Put pci_dev in device tree as early as possible
> 
> in pci/next.
> 
> So we can move that Jiang's patch from your tree to Bjorn's tree?

OK, I'm dropping that patch from my tree, then (hopefully, no one has merged
my acpi-cleanup branch yet).

Bjorn, could you pick up https://patchwork.kernel.org/patch/2003771/ please?

Rafael
Bjorn Helgaas - Feb. 16, 2013, 1:10 a.m.
On Wed, Feb 13, 2013 at 5:59 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Tuesday, February 12, 2013 05:54:08 PM Yinghai Lu wrote:
>> On Tue, Feb 12, 2013 at 4:16 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
>> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> >
>> > After commit 1aeae82 (ACPI / PCI: avoid building pci_slot as module)
>> > the pci_slot driver's .add() callback routine, acpi_pci_slot_add(),
>> > is executed from within acpi_pci_root_add() before the PCI devices on
>> > the bus are enumerated and that triggers the WARN_ON() in
>> > kobject_get():
>> >
>> > WARNING: at /scratch/rafael/work/test/include/linux/kref.h:42 kobject_get+0x33/0x40()
>> > Hardware name: PORTEGE R500
>> > Modules linked in:
>> > Pid: 1, comm: swapper/0 Not tainted 3.8.0-rc7+ #160
>> > Call Trace:
>> >  [<ffffffff8103d38a>] warn_slowpath_common+0x7a/0xb0
>> >  [<ffffffff8103d3d5>] warn_slowpath_null+0x15/0x20
>> >  [<ffffffff812f99b3>] kobject_get+0x33/0x40
>> >  [<ffffffff81452b82>] get_device+0x12/0x30
>> >  [<ffffffff8138df7b>] register_slot+0x243/0x295
>> >  [<ffffffff810a7b6d>] ? trace_hardirqs_on+0xd/0x10
>> >  [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
>> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>> >  [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
>> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>> >  [<ffffffff8138dcf5>] walk_p2p_bridge+0xf8/0x13b
>> >  [<ffffffff8134d606>] ? acpi_os_signal_semaphore+0x76/0x87
>> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>> >  [<ffffffff8137b7b9>] acpi_ns_walk_namespace+0x10f/0x24a
>> >  [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
>> >  [<ffffffff8138dbfd>] ? do_sta_before_sun+0x2b/0x2b
>> >  [<ffffffff8137bdc3>] acpi_walk_namespace+0xe9/0x132
>> >  [<ffffffff81356071>] ? acpi_pci_root_add+0x3e7/0x49a
>> >  [<ffffffff8138e07f>] acpi_pci_slot_add+0xb2/0x103
>> >  [<ffffffff8138dd38>] ? walk_p2p_bridge+0x13b/0x13b
>> >  [<ffffffff81356089>] acpi_pci_root_add+0x3ff/0x49a
>> >
>> > which means that pci_bus->dev used in register_slot() has not been
>> > registered yet at that point.
>> >
>> > To fix this use the observation that before commit 1aeae82
>> > acpi_pci_slot_add() was always run after pci_bus_add_devices()
>> > and that happened to the acpiphp's .add() callback routine too.
>> > Thus it is safe to reorder acpi_pci_root_add() to make the PCI root
>> > drivers' .add() callbacks be run after pci_bus_add_devices(), so do
>> > that.
>> >
>> > This approach was previously proposed by Myron Stowe.
>> >
>> > References: https://patchwork.kernel.org/patch/1848781/
>> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> > ---
>> >
>> > The commit mentioned in the changelog above is in linux-pm.git/linux-next.
>> >
>> > Thanks,
>> > Rafael
>> >
>> > ---
>> >  drivers/acpi/pci_root.c |   13 ++++++++-----
>> >  1 file changed, 8 insertions(+), 5 deletions(-)
>> >
>> > Index: test/drivers/acpi/pci_root.c
>> > ===================================================================
>> > --- test.orig/drivers/acpi/pci_root.c
>> > +++ test/drivers/acpi/pci_root.c
>> > @@ -600,17 +600,20 @@ static int acpi_pci_root_add(struct acpi
>> >         if (system_state != SYSTEM_BOOTING)
>> >                 pci_assign_unassigned_bus_resources(root->bus);
>> >
>> > +       /* need to after hot-added ioapic is registered */
>> > +       if (system_state != SYSTEM_BOOTING)
>> > +               pci_enable_bridges(root->bus);
>> > +
>> > +       pci_bus_add_devices(root->bus);
>> > +
>> >         mutex_lock(&acpi_pci_root_lock);
>> > +
>> >         list_for_each_entry(driver, &acpi_pci_drivers, node)
>> >                 if (driver->add)
>> >                         driver->add(root);
>> > -       mutex_unlock(&acpi_pci_root_lock);
>> >
>> > -       /* need to after hot-added ioapic is registered */
>> > -       if (system_state != SYSTEM_BOOTING)
>> > -               pci_enable_bridges(root->bus);
>> > +       mutex_unlock(&acpi_pci_root_lock);
>> >
>> > -       pci_bus_add_devices(root->bus);
>> >         return 1;
>> >
>> >  out_del_root:
>> >
>>
>> No, we don't need this after
>>
>> | commit 4f535093cf8f6da8cfda7c36c2c1ecd2e9586ee4
>> |     PCI: Put pci_dev in device tree as early as possible
>>
>> in pci/next.
>>
>> So we can move that Jiang's patch from your tree to Bjorn's tree?
>
> OK, I'm dropping that patch from my tree, then (hopefully, no one has merged
> my acpi-cleanup branch yet).
>
> Bjorn, could you pick up https://patchwork.kernel.org/patch/2003771/ please?

I applied this to my next branch for v3.9:

commit ab1a2e038ff2336502e95ec6492c0364a9fc70d0
Author: Jiang Liu <liuj97@gmail.com>
Date:   Sat Jan 19 00:07:42 2013 +0800

    ACPI / PCI: Make pci_slot built-in only, not a module

    As discussed in thread at https://patchwork.kernel.org/patch/1946851/,
    there's no value in supporting CONFIG_ACPI_PCI_SLOT=m any more.
    So change Kconfig and code to only support building pci_slot as
    built-in driver.

Thanks!

Bjorn
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Patch

Index: test/drivers/acpi/pci_root.c
===================================================================
--- test.orig/drivers/acpi/pci_root.c
+++ test/drivers/acpi/pci_root.c
@@ -600,17 +600,20 @@  static int acpi_pci_root_add(struct acpi
 	if (system_state != SYSTEM_BOOTING)
 		pci_assign_unassigned_bus_resources(root->bus);
 
+	/* need to after hot-added ioapic is registered */
+	if (system_state != SYSTEM_BOOTING)
+		pci_enable_bridges(root->bus);
+
+	pci_bus_add_devices(root->bus);
+
 	mutex_lock(&acpi_pci_root_lock);
+
 	list_for_each_entry(driver, &acpi_pci_drivers, node)
 		if (driver->add)
 			driver->add(root);
-	mutex_unlock(&acpi_pci_root_lock);
 
-	/* need to after hot-added ioapic is registered */
-	if (system_state != SYSTEM_BOOTING)
-		pci_enable_bridges(root->bus);
+	mutex_unlock(&acpi_pci_root_lock);
 
-	pci_bus_add_devices(root->bus);
 	return 1;
 
 out_del_root: