Hi,
On Sat, 2011-01-08 at 15:39 +0300, Sergei Shtylyov wrote:
> >> I see no dereference here... Felipe, could you elaborate?
>
> > request would have been dereferenced even if request was NULL, see the
> > return statement:
>
> > return &request->request;
>
> There is no actual dereference here -- we're just taking the address of
> the field. This code works well unless the offset of the 'request' field is
> not 0 (in which case the caller will oops) but it is 0. So this is only a
> potential error...
look at the code before making such comments, seriously:
1133 struct usb_request *musb_alloc_request(struct usb_ep *ep, gfp_t
gfp_flags)
1134 {
1135 struct musb_ep *musb_ep = to_musb_ep(ep);
1136 struct musb_request *request = NULL;
1137
1138 request = kzalloc(sizeof *request, gfp_flags);
1139 if (request) {
1140 INIT_LIST_HEAD(&request->request.list);
1141 request->request.dma = DMA_ADDR_INVALID;
1142 request->epnum = musb_ep->current_epnum;
1143 request->ep = musb_ep;
1144 }
1145
1146 return &request->request;
1147 }
See that struct musb_request *request is the one which is being
allocated. If it ends up being NULL (kzalloc() failed) we will still
dereference it to pass down the pointer to struct usb_request to gadget
driver, so we will be doing:
return &NULL->request;
--
balbi
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