From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH v6] can: kvaser_usb: Add support for Kvaser CAN/USB devices Date: Thu, 22 Nov 2012 13:30:22 -0800 Message-ID: <20121122213022.GB1461@kroah.com> References: <1343626352-24760-1-git-send-email-olivier@sobrie.be> <1353481873-3214-1-git-send-email-olivier@sobrie.be> <20121122150149.GB11612@hposo> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20121122150149.GB11612@hposo> Sender: netdev-owner@vger.kernel.org To: Olivier Sobrie Cc: Wolfgang Grandegger , Marc Kleine-Budde , linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, Daniel Berglund List-Id: linux-can.vger.kernel.org On Thu, Nov 22, 2012 at 04:01:49PM +0100, Olivier Sobrie wrote: > Hi linux-usb folks, > > Is there someone who can help me to fix the following errors? > > smatch warnings: > > + drivers/net/can/usb/kvaser_usb.c:431 kvaser_usb_send_simple_msg() error: doing > +dma on the stack ((null)) > + drivers/net/can/usb/kvaser_usb.c:1073 kvaser_usb_set_opt_mode() error: doing > +dma on the stack ((null)) > + drivers/net/can/usb/kvaser_usb.c:1174 kvaser_usb_flush_queue() error: doing > +dma on the stack ((null)) > + drivers/net/can/usb/kvaser_usb.c:1384 kvaser_usb_set_bittiming() error: doing > +dma on the stack ((null)) > > I assume it's due to the buffer I pass to the function usb_bulk_msg() > which is on the stack and can't be. > Do I just have to kmalloc a buffer and give it to the usb_bulk_msg() > function? That's what I understood by reading > "Documentation/DMA-API-HOWTO.txt" section "What memory is DMA'able?"... > and from commit > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=32ec4576c3fb37316b1d11a04b220527822f3f0d Yes, that is all that is needed. thanks, greg k-h