Re: [PATCH 5/6] virtio/vsock: add support for dgram

[kernel test robot <lkp@intel.com>]

Hi Bobby,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mst-vhost/linux-next]
[also build test WARNING on linus/master v6.0-rc1 next-20220815]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Bobby-Eshleman/virtio-vsock-introduce-dgrams-sk_buff-and-qdisc/20220816-015812
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20220816/202208160405.cG02E3MZ-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/cbb332da78c86ac574688831ed6f404d04d506db
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Bobby-Eshleman/virtio-vsock-introduce-dgrams-sk_buff-and-qdisc/20220816-015812
        git checkout cbb332da78c86ac574688831ed6f404d04d506db
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash net/vmw_vsock/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   net/vmw_vsock/virtio_transport_common.c: In function 'virtio_transport_dgram_do_dequeue':
>> net/vmw_vsock/virtio_transport_common.c:605:13: warning: variable 'free_space' set but not used [-Wunused-but-set-variable]
     605 |         u32 free_space;
         |             ^~~~~~~~~~


vim +/free_space +605 net/vmw_vsock/virtio_transport_common.c

   597	
   598	static ssize_t
   599	virtio_transport_dgram_do_dequeue(struct vsock_sock *vsk,
   600					  struct msghdr *msg, size_t len)
   601	{
   602		struct virtio_vsock_sock *vvs = vsk->trans;
   603		struct sk_buff *skb;
   604		size_t total = 0;
 > 605		u32 free_space;
   606		int err = -EFAULT;
   607	
   608		spin_lock_bh(&vvs->rx_lock);
   609		if (total < len && !skb_queue_empty_lockless(&vvs->rx_queue)) {
   610			skb = __skb_dequeue(&vvs->rx_queue);
   611	
   612			total = len;
   613			if (total > skb->len - vsock_metadata(skb)->off)
   614				total = skb->len - vsock_metadata(skb)->off;
   615			else if (total < skb->len - vsock_metadata(skb)->off)
   616				msg->msg_flags |= MSG_TRUNC;
   617	
   618			/* sk_lock is held by caller so no one else can dequeue.
   619			 * Unlock rx_lock since memcpy_to_msg() may sleep.
   620			 */
   621			spin_unlock_bh(&vvs->rx_lock);
   622	
   623			err = memcpy_to_msg(msg, skb->data + vsock_metadata(skb)->off, total);
   624			if (err)
   625				return err;
   626	
   627			spin_lock_bh(&vvs->rx_lock);
   628	
   629			virtio_transport_dec_rx_pkt(vvs, skb);
   630			consume_skb(skb);
   631		}
   632	
   633		free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt);
   634	
   635		spin_unlock_bh(&vvs->rx_lock);
   636	
   637		if (total > 0 && msg->msg_name) {
   638			/* Provide the address of the sender. */
   639			DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
   640	
   641			vsock_addr_init(vm_addr, le64_to_cpu(vsock_hdr(skb)->src_cid),
   642					le32_to_cpu(vsock_hdr(skb)->src_port));
   643			msg->msg_namelen = sizeof(*vm_addr);
   644		}
   645		return total;
   646	}
   647	

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