linux-kernel - Re: [PATCH v3 02/14] PCI: prevent duplicate slot names

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Date:	Wed, 1 Oct 2008 19:05:42 -0600
From:	Alex Chiang <achiang@...com>
To:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Cc:	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	jbarnes@...tuousgeek.org, kristen.c.accardi@...el.com,
	matthew@....cx
Subject: Re: [PATCH v3 02/14] PCI: prevent duplicate slot names

* Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>:
> Kenji Kaneshige wrote:
>> Hi Alex-san,
>>
>> Here is one comment, though I have not finished reviewing/testing
>> your patches yet (sorry for the delay).
>>
>> Alex Chiang wrote:
>>
>> (snip.)
>>
>>> diff --git a/drivers/pci/hotplug/pci_hotplug_core.c  
>>> b/drivers/pci/hotplug/pci_hotplug_core.c
>>> index 3e37d63..46802dc 100644
>>> --- a/drivers/pci/hotplug/pci_hotplug_core.c
>>> +++ b/drivers/pci/hotplug/pci_hotplug_core.c
>>> @@ -570,39 +570,32 @@ int pci_hp_register(struct hotplug_slot *slot,  
>>> struct pci_bus *bus, int slot_nr,
>>>          return -EINVAL;
>>>      }
>>>  -    /* Check if we have already registered a slot with the same 
>>> name. */
>>> -    if (get_slot_from_name(name))
>>> -        return -EEXIST;
>>> -
>>>      /*
>>> -     * No problems if we call this interface from both ACPI_PCI_SLOT
>>> -     * driver and call it here again. If we've already created the
>>> -     * pci_slot, the interface will simply bump the refcount.
>>> +     * Look for existing slot. If we find it, and it was created by a
>>> +     * slot detection driver (ie, doesn't have a ->hotplug()) then we
>>> +     * allow the hotplug driver calling us to rename the slot if  
>>> desired.
>>> +     *
>>> +     * Otherwise, create the slot and carry on with life.
>>>       */
>>> -    pci_slot = pci_create_slot(bus, slot_nr, name);
>>> -    if (IS_ERR(pci_slot))
>>> -        return PTR_ERR(pci_slot);
>>> -
>>> -    if (pci_slot->hotplug) {
>>> -        dbg("%s: already claimed\n", __func__);
>>> -        pci_destroy_slot(pci_slot);
>>> -        return -EBUSY;
>>> +    pci_slot = pci_get_pci_slot(bus, slot_nr);
>>
>> The pci_get_pci_slot() function refers pci_bus->slots list, so it
>> should be called with pci_bus_sem semaphore held as pci_create_slot()
>> does, or pci_bus_sem semaphore should be held by pci_get_pci_slot()
>> itself.

Yes, I've changed pci_get_pci_slot() to acquire the pci_bus_sem
semaphore.

Thank you for pointing this out.

It will be fixed in v4 of this patch series, which I will send
out after I receive the rest of your review comments.

Thanks!

/ac

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