Hi Yuval,

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Yuval-Mintz/qed-Add-XDP-
support/20161127-225956
config: tile-allmodconfig (attached as .config)
compiler: tilegx-linux-gcc (GCC) 4.6.2
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-
tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=tile

All warnings (new ones prefixed by >>):

   drivers/net/ethernet/qlogic/qede/qede_main.c: In function
'qede_alloc_mem_rxq':

quoted

quoted

drivers/net/ethernet/qlogic/qede/qede_main.c:2960:3: warning: large
integer implicitly truncated to unsigned type [-Woverflow]

vim +2960 drivers/net/ethernet/qlogic/qede/qede_main.c

55482edc Manish Chopra 2016-03-04  2944  err:
55482edc Manish Chopra 2016-03-04  2945  	qede_free_sge_mem(edev,
rxq);
55482edc Manish Chopra 2016-03-04  2946  	edev->gro_disable = 1;
55482edc Manish Chopra 2016-03-04  2947  	return -ENOMEM;
55482edc Manish Chopra 2016-03-04  2948  } 55482edc Manish Chopra 2016-
03-04  2949
2950219d Yuval Mintz   2015-10-26  2950  /* This function allocates all
memory needed per Rx queue */
1a635e48 Yuval Mintz   2016-08-15  2951  static int
qede_alloc_mem_rxq(struct qede_dev *edev, struct qede_rx_queue *rxq)
2950219d Yuval Mintz   2015-10-26  2952  {
f86af2df Manish Chopra 2016-04-20  2953  	int i, rc, size;
2950219d Yuval Mintz   2015-10-26  2954
2950219d Yuval Mintz   2015-10-26  2955  	rxq->num_rx_buffers = edev-

quoted

q_num_rx_buffers;

2950219d Yuval Mintz   2015-10-26  2956
1a635e48 Yuval Mintz   2016-08-15  2957  	rxq->rx_buf_size =
NET_IP_ALIGN + ETH_OVERHEAD + edev->ndev->mtu;
1a635e48 Yuval Mintz   2016-08-15  2958
fc48b7a6 Yuval Mintz   2016-02-15  2959  	if (rxq->rx_buf_size >
PAGE_SIZE)
fc48b7a6 Yuval Mintz   2016-02-15 @2960  		rxq->rx_buf_size =
PAGE_SIZE;

I'd say this is a false positive, given that MTU can't be so large.
Although patch #10 is going to hit the same when setting rx_buf_seg_size
[also a u16] to PAGE_SIZE to make sure there's a single packet per page.

While I can surely address that, I was just wondering about whether this
is an interesting scenario at the moment. I.e., using XDP with 64 Kb pages
is going to be very costly from a memory perspective.