Re: [PATCH 03/23] usb: gadget: f_sourcesink: free requests in sourcesink_disable()

[Peter Chen <peter.chen@freescale.com>]

On Tue, Nov 03, 2015 at 01:53:42PM +0100, Robert Baldyga wrote:
> USB requests in SourceSink function are allocated in sourcesink_get_alt()
> function, so we prefer to free them rather in sourcesink_disable() than
> in source_sink_complete() when request is completed with error. It provides
> better symetry in resource management and improves code readability.
> 
> Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
> ---
>  drivers/usb/gadget/function/f_sourcesink.c | 33 +++++++++++++++++++++++++++---
>  1 file changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_sourcesink.c b/drivers/usb/gadget/function/f_sourcesink.c
> index a8b68c6..d8f5f56 100644
> --- a/drivers/usb/gadget/function/f_sourcesink.c
> +++ b/drivers/usb/gadget/function/f_sourcesink.c
> @@ -22,6 +22,8 @@
>  #include "g_zero.h"
>  #include "u_f.h"
>  
> +#define REQ_CNT	8
> +

It would be buffer if we can have module parameter for this like
qlen at f_loopback.

>  /*
>   * SOURCE/SINK FUNCTION ... a primary testing vehicle for USB peripheral
>   * controller drivers.
> @@ -51,6 +53,11 @@ struct f_sourcesink {
>  	struct usb_ep		*iso_out_ep;
>  	int			cur_alt;
>  
> +	struct usb_request	*in_req;
> +	struct usb_request	*out_req;
> +	struct usb_request	*iso_in_req[REQ_CNT];
> +	struct usb_request	*iso_out_req[REQ_CNT];
> +
>  	unsigned pattern;
>  	unsigned isoc_interval;
>  	unsigned isoc_maxpacket;
> @@ -561,7 +568,6 @@ static void source_sink_complete(struct usb_ep *ep, struct usb_request *req)
>  				req->actual, req->length);
>  		if (ep == ss->out_ep)
>  			check_read_data(ss, req);
> -		free_ep_req(ep, req);

I find the current code may cause memory leak, since above code
is only called one time.

>  		return;
>  
>  	case -EOVERFLOW:		/* buffer overrun on read means that
> @@ -613,7 +619,7 @@ static int source_sink_start_ep(struct f_sourcesink *ss, bool is_in,
>  		ep = is_in ? ss->in_ep : ss->out_ep;
>  	}
>  
> -	for (i = 0; i < 8; i++) {
> +	for (i = 0; i < REQ_CNT; i++) {
>  		req = ss_alloc_ep_req(ep, size);
>  		if (!req)
>  			return -ENOMEM;
> @@ -635,8 +641,18 @@ static int source_sink_start_ep(struct f_sourcesink *ss, bool is_in,
>  			free_ep_req(ep, req);
>  		}
>  
> -		if (!is_iso)
> +		if (is_iso) {
> +			if (is_in)
> +				ss->iso_in_req[i] = req;
> +			else
> +				ss->iso_out_req[i] = req;
> +		} else {
> +			if (is_in)
> +				ss->in_req = req;
> +			else
> +				ss->out_req = req;

The req will be different for both bulk and iso, why you only
have array for iso requests?

>  			break;
> +		}
>  	}
>  
>  	return status;
> @@ -764,8 +780,19 @@ static int sourcesink_get_alt(struct usb_function *f, unsigned intf)
>  static void sourcesink_disable(struct usb_function *f)
>  {
>  	struct f_sourcesink	*ss = func_to_ss(f);
> +	int i;
>  
>  	disable_source_sink(ss);
> +
> +	free_ep_req(ss->in_ep, ss->in_req);
> +	free_ep_req(ss->out_ep, ss->out_req);
> +
> +	if (ss->iso_in_ep) {
> +		for (i = 0; i < REQ_CNT; i++) {
> +			free_ep_req(ss->iso_in_ep, ss->iso_in_req[i]);
> +			free_ep_req(ss->iso_out_ep, ss->iso_out_req[i]);
> +		}
> +	}
>  }
>  
>  /*-------------------------------------------------------------------------*/
> -- 
> 1.9.1
> 
> --
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-- 

Best Regards,
Peter Chen