Re: [PATCH 2/2] drivers: staging: wilc1000: Call kfree only for error cases

[Tony Cho]

On 2015ë 10ì 04ì 19:28, Chandra Gorentla wrote:
> On Sun, Oct 04, 2015 at 09:44:57AM +0100, Greg KH wrote:
> > On Sat, Oct 03, 2015 at 02:57:30PM +0530, Chandra S Gorentla wrote:
> > >   - kfree is being called for the members of the queue without
> > >     de-queuing them; they are just inserted within this function;
> > >     they are supposed to be de-queued and freed in a function
> > >     for receiving the queue items
> > >   - goto statements are removed
> > >   - After kfree correction, there is no need for target block
> > >     of goto statement; hence it is removed
> > >
> > > Signed-off-by: Chandra S Gorentla <csgorentla@xxxxxxxxx>
> > > ---
> > >   drivers/staging/wilc1000/wilc_msgqueue.c | 22 ++++++----------------
> > >   1 file changed, 6 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/drivers/staging/wilc1000/wilc_msgqueue.c b/drivers/staging/wilc1000/wilc_msgqueue.c
> > > index 284a3f5..eae90be 100644
> > > --- a/drivers/staging/wilc1000/wilc_msgqueue.c
> > > +++ b/drivers/staging/wilc1000/wilc_msgqueue.c
> > > @@ -56,32 +56,30 @@ int wilc_mq_destroy(WILC_MsgQueueHandle *pHandle)
> > >   int wilc_mq_send(WILC_MsgQueueHandle *pHandle,
> > >   			     const void *pvSendBuffer, u32 u32SendBufferSize)
> > >   {
> > > -	int result = 0;
> > >   	unsigned long flags;
> > >   	Message *pstrMessage = NULL;
> > >   
> > >   	if ((!pHandle) || (u32SendBufferSize == 0) || (!pvSendBuffer)) {
> > >   		PRINT_ER("pHandle or pvSendBuffer is null\n");
> > > -		result = -EFAULT;
> > > -		goto ERRORHANDLER;
> > > +		return -EFAULT;
> > >   	}
> > >   
> > >   	if (pHandle->bExiting) {
> > >   		PRINT_ER("pHandle fail\n");
> > > -		result = -EFAULT;
> > > -		goto ERRORHANDLER;
> > > +		return -EFAULT;
> > >   	}
> > >   
> > >   	/* construct a new message */
> > >   	pstrMessage = kmalloc(sizeof(Message), GFP_ATOMIC);
> > >   	if (!pstrMessage)
> > >   		return -ENOMEM;
> > > +
> > >   	pstrMessage->u32Length = u32SendBufferSize;
> > >   	pstrMessage->pstrNext = NULL;
> > >   	pstrMessage->pvBuffer = kmalloc(u32SendBufferSize, GFP_ATOMIC);
> > >   	if (!pstrMessage->pvBuffer) {
> > > -		result = -ENOMEM;
> > > -		goto ERRORHANDLER;
> > > +		kfree(pstrMessage);
> > > +		return -ENOMEM;
> > >   	}
> > >   	memcpy(pstrMessage->pvBuffer, pvSendBuffer, u32SendBufferSize);
> > >   
> > > @@ -102,15 +100,7 @@ int wilc_mq_send(WILC_MsgQueueHandle *pHandle,
> > >   	spin_unlock_irqrestore(&pHandle->strCriticalSection, flags);
> > >   
> > >   	up(&pHandle->hSem);
> > > -
> > > -ERRORHANDLER:
> > > -	/* error occured, free any allocations */
> > > -	if (pstrMessage) {
> > > -		kfree(pstrMessage->pvBuffer);
> > > -		kfree(pstrMessage);
> > > -	}
> > > -
> > > -	return result;
> > > +	return 0;
> > Aren't you now leaking memory as you aren't freeing pstrMessage and the
> > buffer on the "normal" return path?
> In the normal path kfree is called in a separate (wilc_mq_recv) function.
> The purpose of the currently modified function (wilc_mq_send) is to post
> a message to a queue by allocating memory for the message.  The receiver
> function is supposed to remove the message from the queue and free the
> memory.
This patch is reasonable and normal free is done in recv function as Chandra said.

Thanks,

Tony.

> > thanks,
> >
> > greg k-h
>
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