> -----Original Message----- > From: Yuanhan Liu [mailto:yuanhan.liu at linux.intel.com] > Sent: Monday, June 13, 2016 4:58 PM > To: Tan, Jianfeng > Cc: dev at dpdk.org; Xie, Huawei > Subject: Re: [PATCH] virito: fix reuse index in nested loop > > On Sun, Jun 12, 2016 at 10:05:45AM +0000, Jianfeng Tan wrote: > > This patches fixes problem of reusing index of outmost loop in nested > > loops. This bug will lead to failure when starting a multi queue > > virtio device: rx queues (except from the first one) cannot be started, > > expecially their vq_ring cannot be initialized, so that when invoking > > rx func on these queues, segment fault happens. > > > > Fixes: a900472aedef ("virtio: split virtio Rx/Tx queue") > > Good catch! > > > Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com> > > --- > > drivers/net/virtio/virtio_rxtx.c | 36 ++++++++++++++++++++---------------- > > 1 file changed, 20 insertions(+), 16 deletions(-) > > > > diff --git a/drivers/net/virtio/virtio_rxtx.c > > b/drivers/net/virtio/virtio_rxtx.c > > index 2e7205b..b96d0cb 100644 > > --- a/drivers/net/virtio/virtio_rxtx.c > > +++ b/drivers/net/virtio/virtio_rxtx.c > > @@ -331,7 +331,7 @@ virtio_dev_rxtx_start(struct rte_eth_dev *dev) > > * - Allocate blank mbufs for the each rx descriptor > > * > > */ > > - int i; > > + int i, j; > > However, I don't quite like using "i, j, k" stuff. So, how about > renaming "j" to "ring_idx"? > > > PMD_INIT_FUNC_TRACE(); > > > > @@ -352,15 +352,18 @@ virtio_dev_rxtx_start(struct rte_eth_dev *dev) > > error = ENOSPC; > > > > #ifdef RTE_MACHINE_CPUFLAG_SSSE3 > > - if (use_simple_rxtx) > > - for (i = 0; i < vq->vq_nentries; i++) { > > - vq->vq_ring.avail->ring[i] = i; > > - vq->vq_ring.desc[i].flags = > VRING_DESC_F_WRITE; > > + if (use_simple_rxtx) { > > + uint16_t k; > > We could reuse "ring_idx" here; no need to define yet another iterate var > for that.
Make sense. Besides, since comparison between unsigned and signed is a violation to static code analyzer, I'll redefine these variables as unsigned. Such as, int i -> uint16_t q_idx int j -> uint16_t r_idx k -> r_idx Thanks, Jianfeng > > --yliu
