Re: [PATCH 4/5] usb: chipidea: udc: manage dynamic amount of tds with an linked list

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On Fri, Mar 01, 2013 at 03:42:26PM +0100, Michael Grzeschik wrote:
> Instead of having a limited number of usable tds in the udc we use a
> linked list to support dynamic amount of needed tds for all special
> gadget types. This improves throughput.
> 
> This patch also adresses a possible momory leak in _ep_nuke found
> while porting the request handling to an linked list.
> 
> 	- The call of _ep_nuke can lead to an memory leak, if it is called on an
> 	  endpoint with currently dynamic allocated tds. This was aswell a problem
> 	  in the special case before the dynamic td handling was implemented and
> 	  an zero length packet was added to mark the end of the transfer.

It is another problem, better have another commit, besides, can you
describe more detail?

> +
> +static int add_td_to_list(struct ci13xxx_ep *mEp, struct ci13xxx_req *mReq, unsigned length)
> +{
> +	struct td_node *lastnode, *node = kzalloc(sizeof(struct td_node), GFP_ATOMIC);

Better split above one line to two lines like below "dma_pool_alloc"

> +
> +	if (node == NULL)
> +		return -ENOMEM;
> +
> +	node->ptr = dma_pool_alloc(mEp->td_pool, GFP_ATOMIC,
> +				   &node->dma);
> +	if (node->ptr == NULL) {
> +		kfree(node);
> +		return -ENOMEM;
> +	}
> +
> +	setup_td_bits(node, length);
> +
> +	/* get the last entry */
> +	lastnode = list_entry(mReq->tds.prev,
> +			struct td_node, td);
> +	lastnode->ptr->next = node->dma;
> +
> +	INIT_LIST_HEAD(&node->td);
> +	list_add_tail(&node->td, &mReq->tds);
> +
> +	return 0;
> +}
> +
>  /**

-- 

Best Regards,
Peter Chen

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