[dpdk-dev,v2] examples/vhost: fix strict aliasing error on gcc 4.4.7
Commit Message
From: "De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
Fixes following error on gcc 4.4.7:
make: Entering directory `/tmp/dpdk-tmp/examples/vhost'
CC main.o
cc1: warnings being treated as errors
/tmp/dpdk-tmp/examples/vhost/main.c: In function ‘new_device’:
/tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740: error:
dereferencing pointer ‘mbuf.486’ does break strict-aliasing rules
/tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
...
/tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
/tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740: error:
dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules
/tmp/dpdk-tmp/examples/vhost/main.c:1804: note: initialized from here
make[1]: *** [main.o] Error 1
Fixes: d19533e8 ("examples/vhost: copy old vhost example")
Reported-by: Qian Xu <qian.q.xu@intel.com>
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
---
Changes in v2:
- Remove unnecessary casting
examples/vhost/main.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
Comments
On Wed, Dec 09, 2015 at 09:39:59AM +0000, Pablo de Lara wrote:
> From: "De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
>
> Fixes following error on gcc 4.4.7:
>
> make: Entering directory `/tmp/dpdk-tmp/examples/vhost'
> CC main.o
> cc1: warnings being treated as errors
> /tmp/dpdk-tmp/examples/vhost/main.c: In function ‘new_device’:
> /tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740: error:
> dereferencing pointer ‘mbuf.486’ does break strict-aliasing rules
> /tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
> ...
> /tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
> /tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740: error:
> dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules
> /tmp/dpdk-tmp/examples/vhost/main.c:1804: note: initialized from here
> make[1]: *** [main.o] Error 1
>
> Fixes: d19533e8 ("examples/vhost: copy old vhost example")
>
> Reported-by: Qian Xu <qian.q.xu@intel.com>
> Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
> ---
> Changes in v2:
> - Remove unnecessary casting
You've remove some, but not all unnecessary casting. You don't need a cast when
assigning void * to any other type, so you can remove the mbuf casts too.
/Bruce
On 12/9/2015 5:40 PM, De Lara Guarch, Pablo wrote:
> From: "De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
>
> Fixes following error on gcc 4.4.7:
>
> make: Entering directory `/tmp/dpdk-tmp/examples/vhost'
> CC main.o
> cc1: warnings being treated as errors
> /tmp/dpdk-tmp/examples/vhost/main.c: In function ‘new_device’:
> /tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740: error:
> dereferencing pointer ‘mbuf.486’ does break strict-aliasing rules
> /tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
> ...
> /tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
> /tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740: error:
> dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules
> /tmp/dpdk-tmp/examples/vhost/main.c:1804: note: initialized from here
> make[1]: *** [main.o] Error 1
>
> Fixes: d19533e8 ("examples/vhost: copy old vhost example")
>
> Reported-by: Qian Xu <qian.q.xu@intel.com>
> Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>
Hi Huawei,
> -----Original Message-----
> From: Xie, Huawei
> Sent: Wednesday, December 09, 2015 10:45 AM
> To: De Lara Guarch, Pablo; dev@dpdk.org
> Cc: yuanhan.liu@linux.intel.com
> Subject: Re: [PATCH v2] examples/vhost: fix strict aliasing error on gcc 4.4.7
>
> On 12/9/2015 5:40 PM, De Lara Guarch, Pablo wrote:
> > From: "De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
> >
> > Fixes following error on gcc 4.4.7:
> >
> > make: Entering directory `/tmp/dpdk-tmp/examples/vhost'
> > CC main.o
> > cc1: warnings being treated as errors
> > /tmp/dpdk-tmp/examples/vhost/main.c: In function 'new_device':
> > /tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740:
> error:
> > dereferencing pointer 'mbuf.486' does break strict-aliasing rules
> > /tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
> > ...
> > /tmp/dpdk-tmp/examples/vhost/main.c:1503: note: initialized from here
> > /tmp/dpdk-tmp/x86_64-native-linuxapp-gcc/include/rte_ring.h:740:
> error:
> > dereferencing pointer '({anonymous})' does break strict-aliasing rules
> > /tmp/dpdk-tmp/examples/vhost/main.c:1804: note: initialized from here
> > make[1]: *** [main.o] Error 1
> >
> > Fixes: d19533e8 ("examples/vhost: copy old vhost example")
> >
> > Reported-by: Qian Xu <qian.q.xu@intel.com>
> > Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
> Acked-by: Huawei Xie <huawei.xie@intel.com>
>
I am going to send a v3 for this patch, removing the other casting that Bruce mentioned.
I will pre-ack it, unless you have any concerns.
Thanks,
Pablo
@@ -1449,7 +1449,8 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
uint64_t buff_addr, phys_addr;
struct vhost_virtqueue *vq;
struct vring_desc *desc;
- struct rte_mbuf *mbuf = NULL;
+ void *obj = NULL;
+ struct rte_mbuf *mbuf;
struct vpool *vpool;
hpa_type addr_type;
struct vhost_dev *vdev = (struct vhost_dev *)dev->priv;
@@ -1500,7 +1501,8 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
}
} while (unlikely(phys_addr == 0));
- rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
+ rte_ring_sc_dequeue(vpool->ring, &obj);
+ mbuf = (struct rte_mbuf *)obj;
if (unlikely(mbuf == NULL)) {
LOG_DEBUG(VHOST_DATA,
"(%"PRIu64") in attach_rxmbuf_zcp: "
@@ -1517,7 +1519,7 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
"size required: %d\n",
dev->device_fh, desc->len, desc_idx, vpool->buf_size);
put_desc_to_used_list_zcp(vq, desc_idx);
- rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
+ rte_ring_sp_enqueue(vpool->ring, obj);
return;
}
@@ -1789,7 +1791,8 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
{
struct mbuf_table *tx_q;
struct rte_mbuf **m_table;
- struct rte_mbuf *mbuf = NULL;
+ void *obj = NULL;
+ struct rte_mbuf *mbuf;
unsigned len, ret, offset = 0;
struct vpool *vpool;
uint16_t vlan_tag = (uint16_t)vlan_tags[(uint16_t)dev->device_fh];
@@ -1801,7 +1804,8 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
/* Allocate an mbuf and populate the structure. */
vpool = &vpool_array[MAX_QUEUES + vmdq_rx_q];
- rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
+ rte_ring_sc_dequeue(vpool->ring, &obj);
+ mbuf = (struct rte_mbuf *)obj;
if (unlikely(mbuf == NULL)) {
struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_TXQ];
RTE_LOG(ERR, VHOST_DATA,