diff mbox

[1/4] PCI: introduce helper functions for device flag operation

Message ID 1406045944-1587-2-git-send-email-ethan.zhao@oracle.com
State Not Applicable
Headers show

Commit Message

ethan zhao July 22, 2014, 4:19 p.m. UTC
This patch introduced three helper functions to hide direct
device flag operation.

void pci_set_dev_assigned(struct pci_dev *pdev);
void pci_set_dev_deassigned(struct pci_dev *pdev);
bool pci_is_dev_assigned(struct pci_dev *pdev);

Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
---
 include/linux/pci.h |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

Comments

Alex Williamson July 28, 2014, 9 p.m. UTC | #1
On Wed, 2014-07-23 at 00:19 +0800, Ethan Zhao wrote:
> This patch introduced three helper functions to hide direct
> device flag operation.
> 
> void pci_set_dev_assigned(struct pci_dev *pdev);
> void pci_set_dev_deassigned(struct pci_dev *pdev);
> bool pci_is_dev_assigned(struct pci_dev *pdev);
> 
> Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
> ---
>  include/linux/pci.h |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index aab57b4..5f6f8fa 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1129,6 +1129,19 @@ resource_size_t pcibios_window_alignment(struct pci_bus *bus,
>  
>  int pci_set_vga_state(struct pci_dev *pdev, bool decode,
>  		      unsigned int command_bits, u32 flags);
> +/* helper functions for operation of device flag */
> +static inline void pci_set_dev_assigned(struct pci_dev *pdev)
> +{
> +	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
> +}
> +static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
> +{
> +	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
> +}

I think pci_clear_dev_assigned() would make more sense, we're not
setting a flag named DEASSIGNED.

> +static inline bool pci_is_dev_assigned(struct pci_dev *pdev)
> +{
> +	return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED ? true : false;
> +}

The ternary operation isn't necessary.  Thanks,

Alex

>  /* kmem_cache style wrapper around pci_alloc_consistent() */
>  
>  #include <linux/pci-dma.h>



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ethan zhao July 29, 2014, 1:53 a.m. UTC | #2
On 2014/7/29 5:00, Alex Williamson wrote:
> On Wed, 2014-07-23 at 00:19 +0800, Ethan Zhao wrote:
>> This patch introduced three helper functions to hide direct
>> device flag operation.
>>
>> void pci_set_dev_assigned(struct pci_dev *pdev);
>> void pci_set_dev_deassigned(struct pci_dev *pdev);
>> bool pci_is_dev_assigned(struct pci_dev *pdev);
>>
>> Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
>> ---
>>   include/linux/pci.h |   13 +++++++++++++
>>   1 files changed, 13 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index aab57b4..5f6f8fa 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -1129,6 +1129,19 @@ resource_size_t pcibios_window_alignment(struct pci_bus *bus,
>>   
>>   int pci_set_vga_state(struct pci_dev *pdev, bool decode,
>>   		      unsigned int command_bits, u32 flags);
>> +/* helper functions for operation of device flag */
>> +static inline void pci_set_dev_assigned(struct pci_dev *pdev)
>> +{
>> +	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
>> +}
>> +static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
>> +{
>> +	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
>> +}
> I think pci_clear_dev_assigned() would make more sense, we're not
> setting a flag named DEASSIGNED.
   Though it is a flag operation now, may not later, we define it 
because we want to hide the internal operation.
   'set' to 'deassigned'  status is enough. So I would like keep it.
>
>> +static inline bool pci_is_dev_assigned(struct pci_dev *pdev)
>> +{
>> +	return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED ? true : false;
>> +}
> The ternary operation isn't necessary.  Thanks,
   Yep,

   return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED

   is enough.

   Thanks,
   Ethan
>
> Alex
>
>>   /* kmem_cache style wrapper around pci_alloc_consistent() */
>>   
>>   #include <linux/pci-dma.h>
>
>

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Alex Williamson July 29, 2014, 2:31 a.m. UTC | #3
On Tue, 2014-07-29 at 09:53 +0800, ethan zhao wrote:
> On 2014/7/29 5:00, Alex Williamson wrote:
> > On Wed, 2014-07-23 at 00:19 +0800, Ethan Zhao wrote:
> >> This patch introduced three helper functions to hide direct
> >> device flag operation.
> >>
> >> void pci_set_dev_assigned(struct pci_dev *pdev);
> >> void pci_set_dev_deassigned(struct pci_dev *pdev);
> >> bool pci_is_dev_assigned(struct pci_dev *pdev);
> >>
> >> Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
> >> ---
> >>   include/linux/pci.h |   13 +++++++++++++
> >>   1 files changed, 13 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/include/linux/pci.h b/include/linux/pci.h
> >> index aab57b4..5f6f8fa 100644
> >> --- a/include/linux/pci.h
> >> +++ b/include/linux/pci.h
> >> @@ -1129,6 +1129,19 @@ resource_size_t pcibios_window_alignment(struct pci_bus *bus,
> >>   
> >>   int pci_set_vga_state(struct pci_dev *pdev, bool decode,
> >>   		      unsigned int command_bits, u32 flags);
> >> +/* helper functions for operation of device flag */
> >> +static inline void pci_set_dev_assigned(struct pci_dev *pdev)
> >> +{
> >> +	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
> >> +}
> >> +static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
> >> +{
> >> +	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
> >> +}
> > I think pci_clear_dev_assigned() would make more sense, we're not
> > setting a flag named DEASSIGNED.
>    Though it is a flag operation now, may not later, we define it 
> because we want to hide the internal operation.
>    'set' to 'deassigned'  status is enough. So I would like keep it.

I disagree, the opposite of a 'set' is a 'clear', or at least an
'unset'.  Using bit-ops-like terminology doesn't lock us into an
implementation.  As written, this could just as easily be setting two
different variables.

> >
> >> +static inline bool pci_is_dev_assigned(struct pci_dev *pdev)
> >> +{
> >> +	return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED ? true : false;
> >> +}
> > The ternary operation isn't necessary.  Thanks,
>    Yep,
> 
>    return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED
> 
>    is enough.
> 
>    Thanks,
>    Ethan
> >
> > Alex
> >
> >>   /* kmem_cache style wrapper around pci_alloc_consistent() */
> >>   
> >>   #include <linux/pci-dma.h>
> >
> >
> 



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ethan zhao July 29, 2014, 2:43 a.m. UTC | #4
On 2014/7/29 10:31, Alex Williamson wrote:
> On Tue, 2014-07-29 at 09:53 +0800, ethan zhao wrote:
>> On 2014/7/29 5:00, Alex Williamson wrote:
>>> On Wed, 2014-07-23 at 00:19 +0800, Ethan Zhao wrote:
>>>> This patch introduced three helper functions to hide direct
>>>> device flag operation.
>>>>
>>>> void pci_set_dev_assigned(struct pci_dev *pdev);
>>>> void pci_set_dev_deassigned(struct pci_dev *pdev);
>>>> bool pci_is_dev_assigned(struct pci_dev *pdev);
>>>>
>>>> Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
>>>> ---
>>>>    include/linux/pci.h |   13 +++++++++++++
>>>>    1 files changed, 13 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>>>> index aab57b4..5f6f8fa 100644
>>>> --- a/include/linux/pci.h
>>>> +++ b/include/linux/pci.h
>>>> @@ -1129,6 +1129,19 @@ resource_size_t pcibios_window_alignment(struct pci_bus *bus,
>>>>    
>>>>    int pci_set_vga_state(struct pci_dev *pdev, bool decode,
>>>>    		      unsigned int command_bits, u32 flags);
>>>> +/* helper functions for operation of device flag */
>>>> +static inline void pci_set_dev_assigned(struct pci_dev *pdev)
>>>> +{
>>>> +	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
>>>> +}
>>>> +static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
>>>> +{
>>>> +	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
>>>> +}
>>> I think pci_clear_dev_assigned() would make more sense, we're not
>>> setting a flag named DEASSIGNED.
>>     Though it is a flag operation now, may not later, we define it
>> because we want to hide the internal operation.
>>     'set' to 'deassigned'  status is enough. So I would like keep it.
> I disagree, the opposite of a 'set' is a 'clear', or at least an
> 'unset'.  Using bit-ops-like terminology doesn't lock us into an
> implementation.  As written, this could just as easily be setting two
> different variables.
  So there are two pairs of opposite:

  set assigned ---> unset assigned
  set assigned ---> set deassigned

  Here you prefer the 'verb' set /unset, and I prefer the 'adj.' 
assigned / deassigned.

  Do they really have different meaning or make confusion ? I don't 
think so.

  Thanks,
  Ethan

>
>>>> +static inline bool pci_is_dev_assigned(struct pci_dev *pdev)
>>>> +{
>>>> +	return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED ? true : false;
>>>> +}
>>> The ternary operation isn't necessary.  Thanks,
>>     Yep,
>>
>>     return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED
>>
>>     is enough.
>>
>>     Thanks,
>>     Ethan
>>> Alex
>>>
>>>>    /* kmem_cache style wrapper around pci_alloc_consistent() */
>>>>    
>>>>    #include <linux/pci-dma.h>
>>>
>
>

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Alexander H Duyck July 29, 2014, 3:37 a.m. UTC | #5
On 07/28/2014 07:43 PM, ethan zhao wrote:
> 
> On 2014/7/29 10:31, Alex Williamson wrote:
>> On Tue, 2014-07-29 at 09:53 +0800, ethan zhao wrote:
>>> On 2014/7/29 5:00, Alex Williamson wrote:
>>>> On Wed, 2014-07-23 at 00:19 +0800, Ethan Zhao wrote:
>>>>> This patch introduced three helper functions to hide direct
>>>>> device flag operation.
>>>>>
>>>>> void pci_set_dev_assigned(struct pci_dev *pdev);
>>>>> void pci_set_dev_deassigned(struct pci_dev *pdev);
>>>>> bool pci_is_dev_assigned(struct pci_dev *pdev);
>>>>>
>>>>> Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
>>>>> ---
>>>>>    include/linux/pci.h |   13 +++++++++++++
>>>>>    1 files changed, 13 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>>>>> index aab57b4..5f6f8fa 100644
>>>>> --- a/include/linux/pci.h
>>>>> +++ b/include/linux/pci.h
>>>>> @@ -1129,6 +1129,19 @@ resource_size_t
>>>>> pcibios_window_alignment(struct pci_bus *bus,
>>>>>       int pci_set_vga_state(struct pci_dev *pdev, bool decode,
>>>>>                  unsigned int command_bits, u32 flags);
>>>>> +/* helper functions for operation of device flag */
>>>>> +static inline void pci_set_dev_assigned(struct pci_dev *pdev)
>>>>> +{
>>>>> +    pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
>>>>> +}
>>>>> +static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
>>>>> +{
>>>>> +    pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
>>>>> +}
>>>> I think pci_clear_dev_assigned() would make more sense, we're not
>>>> setting a flag named DEASSIGNED.
>>>     Though it is a flag operation now, may not later, we define it
>>> because we want to hide the internal operation.
>>>     'set' to 'deassigned'  status is enough. So I would like keep it.
>> I disagree, the opposite of a 'set' is a 'clear', or at least an
>> 'unset'.  Using bit-ops-like terminology doesn't lock us into an
>> implementation.  As written, this could just as easily be setting two
>> different variables.
>  So there are two pairs of opposite:
> 
>  set assigned ---> unset assigned
>  set assigned ---> set deassigned
> 
>  Here you prefer the 'verb' set /unset, and I prefer the 'adj.' assigned
> / deassigned.
> 
>  Do they really have different meaning or make confusion ? I don't think
> so.
> 
>  Thanks,
>  Ethan
> 

I agree with Alex W.  If you are going to use the "set" name you should
probably use "clear" for the operation that undoes it.  Using the term
set implies that it is setting a bit and we currently don't have a
deassigned/unassigned bit.

If that doesn't work perhaps you could use something like
get/put_assigned_device or acquire/release_assigned_device.  You just
need to describe what it is you are doing.  You could even consider
adding some tests to return an error if you attempt to assign a device
that is already assigned.

Thanks,

Alex D

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Ethan Zhao July 29, 2014, 3:47 a.m. UTC | #6
Both of you and Alex W prefer the 'Verb' , Ok,  I accept the suggestion.

Thanks,
Ethan


On Tue, Jul 29, 2014 at 11:37 AM, Alexander Duyck
<alexander.duyck@gmail.com> wrote:
> On 07/28/2014 07:43 PM, ethan zhao wrote:
>>
>> On 2014/7/29 10:31, Alex Williamson wrote:
>>> On Tue, 2014-07-29 at 09:53 +0800, ethan zhao wrote:
>>>> On 2014/7/29 5:00, Alex Williamson wrote:
>>>>> On Wed, 2014-07-23 at 00:19 +0800, Ethan Zhao wrote:
>>>>>> This patch introduced three helper functions to hide direct
>>>>>> device flag operation.
>>>>>>
>>>>>> void pci_set_dev_assigned(struct pci_dev *pdev);
>>>>>> void pci_set_dev_deassigned(struct pci_dev *pdev);
>>>>>> bool pci_is_dev_assigned(struct pci_dev *pdev);
>>>>>>
>>>>>> Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
>>>>>> ---
>>>>>>    include/linux/pci.h |   13 +++++++++++++
>>>>>>    1 files changed, 13 insertions(+), 0 deletions(-)
>>>>>>
>>>>>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>>>>>> index aab57b4..5f6f8fa 100644
>>>>>> --- a/include/linux/pci.h
>>>>>> +++ b/include/linux/pci.h
>>>>>> @@ -1129,6 +1129,19 @@ resource_size_t
>>>>>> pcibios_window_alignment(struct pci_bus *bus,
>>>>>>       int pci_set_vga_state(struct pci_dev *pdev, bool decode,
>>>>>>                  unsigned int command_bits, u32 flags);
>>>>>> +/* helper functions for operation of device flag */
>>>>>> +static inline void pci_set_dev_assigned(struct pci_dev *pdev)
>>>>>> +{
>>>>>> +    pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
>>>>>> +}
>>>>>> +static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
>>>>>> +{
>>>>>> +    pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
>>>>>> +}
>>>>> I think pci_clear_dev_assigned() would make more sense, we're not
>>>>> setting a flag named DEASSIGNED.
>>>>     Though it is a flag operation now, may not later, we define it
>>>> because we want to hide the internal operation.
>>>>     'set' to 'deassigned'  status is enough. So I would like keep it.
>>> I disagree, the opposite of a 'set' is a 'clear', or at least an
>>> 'unset'.  Using bit-ops-like terminology doesn't lock us into an
>>> implementation.  As written, this could just as easily be setting two
>>> different variables.
>>  So there are two pairs of opposite:
>>
>>  set assigned ---> unset assigned
>>  set assigned ---> set deassigned
>>
>>  Here you prefer the 'verb' set /unset, and I prefer the 'adj.' assigned
>> / deassigned.
>>
>>  Do they really have different meaning or make confusion ? I don't think
>> so.
>>
>>  Thanks,
>>  Ethan
>>
>
> I agree with Alex W.  If you are going to use the "set" name you should
> probably use "clear" for the operation that undoes it.  Using the term
> set implies that it is setting a bit and we currently don't have a
> deassigned/unassigned bit.
>
> If that doesn't work perhaps you could use something like
> get/put_assigned_device or acquire/release_assigned_device.  You just
> need to describe what it is you are doing.  You could even consider
> adding some tests to return an error if you attempt to assign a device
> that is already assigned.
>
> Thanks,
>
> Alex D
>
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diff mbox

Patch

diff --git a/include/linux/pci.h b/include/linux/pci.h
index aab57b4..5f6f8fa 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1129,6 +1129,19 @@  resource_size_t pcibios_window_alignment(struct pci_bus *bus,
 
 int pci_set_vga_state(struct pci_dev *pdev, bool decode,
 		      unsigned int command_bits, u32 flags);
+/* helper functions for operation of device flag */
+static inline void pci_set_dev_assigned(struct pci_dev *pdev)
+{
+	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
+}
+static inline void pci_set_dev_deassigned(struct pci_dev *pdev)
+{
+	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
+}
+static inline bool pci_is_dev_assigned(struct pci_dev *pdev)
+{
+	return pdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED ? true : false;
+}
 /* kmem_cache style wrapper around pci_alloc_consistent() */
 
 #include <linux/pci-dma.h>