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* [PATCH] HID: usbhid: Use GFP_KERNEL instead of GFP_ATOMIC when applicable
@ 2019-08-01  7:47 Christophe JAILLET
  2019-08-01 10:06 ` walter harms
  0 siblings, 1 reply; 4+ messages in thread
From: Christophe JAILLET @ 2019-08-01  7:47 UTC (permalink / raw)
  To: jikos, benjamin.tissoires
  Cc: linux-usb, linux-input, linux-kernel, kernel-janitors,
	Christophe JAILLET

There is no need to use GFP_ATOMIC when calling 'usb_alloc_coherent()'
here. These calls are done from probe functions and using GFP_KERNEL should
be safe.
The memory itself is used within some interrupts, but it is not a
problem, once it has been allocated.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/hid/usbhid/usbkbd.c   | 4 ++--
 drivers/hid/usbhid/usbmouse.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/usbhid/usbkbd.c b/drivers/hid/usbhid/usbkbd.c
index d5b7a696a68c..63e8ef8beb45 100644
--- a/drivers/hid/usbhid/usbkbd.c
+++ b/drivers/hid/usbhid/usbkbd.c
@@ -239,11 +239,11 @@ static int usb_kbd_alloc_mem(struct usb_device *dev, struct usb_kbd *kbd)
 		return -1;
 	if (!(kbd->led = usb_alloc_urb(0, GFP_KERNEL)))
 		return -1;
-	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma)))
+	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_KERNEL, &kbd->new_dma)))
 		return -1;
 	if (!(kbd->cr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL)))
 		return -1;
-	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_ATOMIC, &kbd->leds_dma)))
+	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_KERNEL, &kbd->leds_dma)))
 		return -1;
 
 	return 0;
diff --git a/drivers/hid/usbhid/usbmouse.c b/drivers/hid/usbhid/usbmouse.c
index 073127e65ac1..c89332017d5d 100644
--- a/drivers/hid/usbhid/usbmouse.c
+++ b/drivers/hid/usbhid/usbmouse.c
@@ -130,7 +130,7 @@ static int usb_mouse_probe(struct usb_interface *intf, const struct usb_device_i
 	if (!mouse || !input_dev)
 		goto fail1;
 
-	mouse->data = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &mouse->data_dma);
+	mouse->data = usb_alloc_coherent(dev, 8, GFP_KERNEL, &mouse->data_dma);
 	if (!mouse->data)
 		goto fail1;
 
-- 
2.20.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] HID: usbhid: Use GFP_KERNEL instead of GFP_ATOMIC when applicable
  2019-08-01  7:47 [PATCH] HID: usbhid: Use GFP_KERNEL instead of GFP_ATOMIC when applicable Christophe JAILLET
@ 2019-08-01 10:06 ` walter harms
  2019-08-01 13:47   ` Greg KH
  2019-08-02  7:51   ` Christophe JAILLET
  0 siblings, 2 replies; 4+ messages in thread
From: walter harms @ 2019-08-01 10:06 UTC (permalink / raw)
  To: Christophe JAILLET
  Cc: jikos, benjamin.tissoires, linux-usb, linux-input, linux-kernel,
	kernel-janitors



Am 01.08.2019 09:47, schrieb Christophe JAILLET:
> There is no need to use GFP_ATOMIC when calling 'usb_alloc_coherent()'
> here. These calls are done from probe functions and using GFP_KERNEL should
> be safe.
> The memory itself is used within some interrupts, but it is not a
> problem, once it has been allocated.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  drivers/hid/usbhid/usbkbd.c   | 4 ++--
>  drivers/hid/usbhid/usbmouse.c | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hid/usbhid/usbkbd.c b/drivers/hid/usbhid/usbkbd.c
> index d5b7a696a68c..63e8ef8beb45 100644
> --- a/drivers/hid/usbhid/usbkbd.c
> +++ b/drivers/hid/usbhid/usbkbd.c
> @@ -239,11 +239,11 @@ static int usb_kbd_alloc_mem(struct usb_device *dev, struct usb_kbd *kbd)
>  		return -1;
>  	if (!(kbd->led = usb_alloc_urb(0, GFP_KERNEL)))
>  		return -1;
> -	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma)))
> +	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_KERNEL, &kbd->new_dma)))
>  		return -1;
>  	if (!(kbd->cr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL)))
>  		return -1;
> -	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_ATOMIC, &kbd->leds_dma)))
> +	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_KERNEL, &kbd->leds_dma)))
>  		return -1;
>  

the kernel style is usually:
 kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma);
 if (!kbd->new)
	return -1;


in usbmouse.c this is done, any reason for the change here ?

re,
 wh

>  	return 0;
> diff --git a/drivers/hid/usbhid/usbmouse.c b/drivers/hid/usbhid/usbmouse.c
> index 073127e65ac1..c89332017d5d 100644
> --- a/drivers/hid/usbhid/usbmouse.c
> +++ b/drivers/hid/usbhid/usbmouse.c
> @@ -130,7 +130,7 @@ static int usb_mouse_probe(struct usb_interface *intf, const struct usb_device_i
>  	if (!mouse || !input_dev)
>  		goto fail1;
>  
> -	mouse->data = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &mouse->data_dma);
> +	mouse->data = usb_alloc_coherent(dev, 8, GFP_KERNEL, &mouse->data_dma);
>  	if (!mouse->data)
>  		goto fail1;
>  

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] HID: usbhid: Use GFP_KERNEL instead of GFP_ATOMIC when applicable
  2019-08-01 10:06 ` walter harms
@ 2019-08-01 13:47   ` Greg KH
  2019-08-02  7:51   ` Christophe JAILLET
  1 sibling, 0 replies; 4+ messages in thread
From: Greg KH @ 2019-08-01 13:47 UTC (permalink / raw)
  To: walter harms
  Cc: Christophe JAILLET, jikos, benjamin.tissoires, linux-usb,
	linux-input, linux-kernel, kernel-janitors

On Thu, Aug 01, 2019 at 12:06:03PM +0200, walter harms wrote:
> 
> 
> Am 01.08.2019 09:47, schrieb Christophe JAILLET:
> > There is no need to use GFP_ATOMIC when calling 'usb_alloc_coherent()'
> > here. These calls are done from probe functions and using GFP_KERNEL should
> > be safe.
> > The memory itself is used within some interrupts, but it is not a
> > problem, once it has been allocated.
> > 
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > ---
> >  drivers/hid/usbhid/usbkbd.c   | 4 ++--
> >  drivers/hid/usbhid/usbmouse.c | 2 +-
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/hid/usbhid/usbkbd.c b/drivers/hid/usbhid/usbkbd.c
> > index d5b7a696a68c..63e8ef8beb45 100644
> > --- a/drivers/hid/usbhid/usbkbd.c
> > +++ b/drivers/hid/usbhid/usbkbd.c
> > @@ -239,11 +239,11 @@ static int usb_kbd_alloc_mem(struct usb_device *dev, struct usb_kbd *kbd)
> >  		return -1;
> >  	if (!(kbd->led = usb_alloc_urb(0, GFP_KERNEL)))
> >  		return -1;
> > -	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma)))
> > +	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_KERNEL, &kbd->new_dma)))
> >  		return -1;
> >  	if (!(kbd->cr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL)))
> >  		return -1;
> > -	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_ATOMIC, &kbd->leds_dma)))
> > +	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_KERNEL, &kbd->leds_dma)))
> >  		return -1;
> >  
> 
> the kernel style is usually:
>  kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma);
>  if (!kbd->new)
> 	return -1;
> 
> 
> in usbmouse.c this is done, any reason for the change here ?

If you want to be extra-correct, don't return -1, return -ENOMEM.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] HID: usbhid: Use GFP_KERNEL instead of GFP_ATOMIC when applicable
  2019-08-01 10:06 ` walter harms
  2019-08-01 13:47   ` Greg KH
@ 2019-08-02  7:51   ` Christophe JAILLET
  1 sibling, 0 replies; 4+ messages in thread
From: Christophe JAILLET @ 2019-08-02  7:51 UTC (permalink / raw)
  To: wharms
  Cc: jikos, benjamin.tissoires, linux-usb, linux-input, linux-kernel,
	kernel-janitors

Hi, (and sorry if you receive this email twice. I've used a web mail 
which sends HTML by default and it was rejected by ML)

Le 01/08/2019 à 12:06, walter harms a écrit :
> 
> 
> Am 01.08.2019 09:47, schrieb Christophe JAILLET:
>> There is no need to use GFP_ATOMIC when calling 'usb_alloc_coherent()'
>> here. These calls are done from probe functions and using GFP_KERNEL should
>> be safe.
>> The memory itself is used within some interrupts, but it is not a
>> problem, once it has been allocated.
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> ---
>>   drivers/hid/usbhid/usbkbd.c   | 4 ++--
>>   drivers/hid/usbhid/usbmouse.c | 2 +-
>>   2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/hid/usbhid/usbkbd.c b/drivers/hid/usbhid/usbkbd.c
>> index d5b7a696a68c..63e8ef8beb45 100644
>> --- a/drivers/hid/usbhid/usbkbd.c
>> +++ b/drivers/hid/usbhid/usbkbd.c
>> @@ -239,11 +239,11 @@ static int usb_kbd_alloc_mem(struct usb_device *dev, struct usb_kbd *kbd)
>>   		return -1;
>>   	if (!(kbd->led = usb_alloc_urb(0, GFP_KERNEL)))
>>   		return -1;
>> -	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma)))
>> +	if (!(kbd->new = usb_alloc_coherent(dev, 8, GFP_KERNEL, &kbd->new_dma)))
>>   		return -1;
>>   	if (!(kbd->cr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL)))
>>   		return -1;
>> -	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_ATOMIC, &kbd->leds_dma)))
>> +	if (!(kbd->leds = usb_alloc_coherent(dev, 1, GFP_KERNEL, &kbd->leds_dma)))
>>   		return -1;
>>   
> 
> the kernel style is usually:
>   kbd->new = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &kbd->new_dma);
>   if (!kbd->new)
> 	return -1;
> 

Searching with coccinelle with:
*   x = usb_alloc_coherent(..., <+... GFP_KERNEL ...+>, ...);
finds 67 files,

whereas:
*   x = usb_alloc_coherent(..., <+... GFP_ATOMIC ...+>, ...);
only finds 11 files.

> 
> in usbmouse.c this is done, any reason for the change here ?
> 

No real reason in fact, just to be consistent with surrounding code.

Unless some allocations are done within a spin_lock/spin_unlock, using 
both GFP_KERNEL and GFP_ATOMIC in the same function looks spurious to me.
Either there is a bug (GFP_KERNEL should be GFP_ATOMIC), or a useless 
constraint is given to the memory allocator.

CJ

> re,
>   wh
> 
>>   	return 0;
>> diff --git a/drivers/hid/usbhid/usbmouse.c b/drivers/hid/usbhid/usbmouse.c
>> index 073127e65ac1..c89332017d5d 100644
>> --- a/drivers/hid/usbhid/usbmouse.c
>> +++ b/drivers/hid/usbhid/usbmouse.c
>> @@ -130,7 +130,7 @@ static int usb_mouse_probe(struct usb_interface *intf, const struct usb_device_i
>>   	if (!mouse || !input_dev)
>>   		goto fail1;
>>   
>> -	mouse->data = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &mouse->data_dma);
>> +	mouse->data = usb_alloc_coherent(dev, 8, GFP_KERNEL, &mouse->data_dma);
>>   	if (!mouse->data)
>>   		goto fail1;
>>   
> 


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2019-08-02  7:51 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-08-01  7:47 [PATCH] HID: usbhid: Use GFP_KERNEL instead of GFP_ATOMIC when applicable Christophe JAILLET
2019-08-01 10:06 ` walter harms
2019-08-01 13:47   ` Greg KH
2019-08-02  7:51   ` Christophe JAILLET

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