Re: [PATCH 1/2] drivers: staging: wilc1000: Move spin lock to the start of critical section

[Tony Cho]

On 2015ë 10ì 04ì 17:43, Greg KH wrote:
> On Sat, Oct 03, 2015 at 02:57:29PM +0530, Chandra S Gorentla wrote:
> > The spin_lock_irqsave is moved to just beginning of critical section.
> > This change moves a couple of return statements out of the lock.
> >
> > Signed-off-by: Chandra S Gorentla <csgorentla@xxxxxxxxx>
> > ---
> >   drivers/staging/wilc1000/wilc_msgqueue.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/staging/wilc1000/wilc_msgqueue.c b/drivers/staging/wilc1000/wilc_msgqueue.c
> > index d5ebd6d..284a3f5 100644
> > --- a/drivers/staging/wilc1000/wilc_msgqueue.c
> > +++ b/drivers/staging/wilc1000/wilc_msgqueue.c
> > @@ -72,8 +72,6 @@ int wilc_mq_send(WILC_MsgQueueHandle *pHandle,
> >   		goto ERRORHANDLER;
> >   	}
> >   
> > -	spin_lock_irqsave(&pHandle->strCriticalSection, flags);
> > -
> >   	/* construct a new message */
> >   	pstrMessage = kmalloc(sizeof(Message), GFP_ATOMIC);
> As you have moved the lock, can you also change this to GFP_KERNEL as
> well because we do not have a lock held?
>
> And how have you tested that this is ok?  What is this lock trying to
> protect?

This function is called even in interrupt context, so GFP_ATOMIC should be called. The spinlock
also should protect pstrMessage from allocating the memory, so we don't place it to the beginning
of critical section as Chandra said.

Thanks,
Tony.

> thanks,
>
> greg k-h
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