* Re: [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
2021-07-07 10:30 [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2 Maxime Coquelin
@ 2021-07-07 11:11 ` Jiang, Cheng1
2021-07-12 6:53 ` Jiang, Cheng1
2021-07-14 5:16 ` Xia, Chenbo
2021-07-20 2:51 ` Xia, Chenbo
2 siblings, 1 reply; 6+ messages in thread
From: Jiang, Cheng1 @ 2021-07-07 11:11 UTC (permalink / raw)
To: Maxime Coquelin, dev, Xia, Chenbo; +Cc: stable
Hi Maxime,
I have also noticed the wrong calculation here, thanks for the timely help.
Thanks,
Cheng
> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, July 7, 2021 6:30 PM
> To: dev@dpdk.org; Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> <chenbo.xia@intel.com>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
> Subject: [PATCH v2] vhost: fix assuming packed ring size is a power of 2
>
> Unlike split ring, packed ring does not mandate the ring size to be a power of
> 2. So we have to use a modulo operation when wrapping ring index.
>
> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> Cc: stable@dpdk.org
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>
> V2: Also fix wrapping in virtio_dev_rx_async_get_info_idx which is used in
> the packed ring data path.
>
> lib/vhost/virtio_net.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
> b93482587c..0de5231db7 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1470,7 +1470,7 @@ virtio_dev_rx_async_get_info_idx(uint16_t
> pkts_idx,
> uint16_t vq_size, uint16_t n_inflight) {
> return pkts_idx > n_inflight ? (pkts_idx - n_inflight) :
> - (vq_size - n_inflight + pkts_idx) & (vq_size - 1);
> + (vq_size - n_inflight + pkts_idx) % vq_size;
> }
>
> static __rte_always_inline void
> @@ -2131,7 +2131,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int
> vid, uint16_t queue_id,
>
> if (vq_is_packed(dev)) {
> for (i = 0; i < n_pkts_put; i++) {
> - from = (start_idx + i) & (vq_size - 1);
> + from = (start_idx + i) % vq_size;
> n_buffers += pkts_info[from].nr_buffers;
> pkts[i] = pkts_info[from].mbuf;
> }
> --
> 2.31.1
Acked-by: Cheng Jiang <cheng1.jiang@intel.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
2021-07-07 11:11 ` Jiang, Cheng1
@ 2021-07-12 6:53 ` Jiang, Cheng1
2021-07-12 9:16 ` Maxime Coquelin
0 siblings, 1 reply; 6+ messages in thread
From: Jiang, Cheng1 @ 2021-07-12 6:53 UTC (permalink / raw)
To: Maxime Coquelin, dev, Xia, Chenbo; +Cc: stable
Hi Maxime,
I have noticed you changed the state this patch to Superseded.
So are you going to submit a new version of this patch?
Thanks,
Cheng
> -----Original Message-----
> From: Jiang, Cheng1
> Sent: Wednesday, July 7, 2021 7:11 PM
> To: Maxime Coquelin <maxime.coquelin@redhat.com>; dev@dpdk.org; Xia,
> Chenbo <Chenbo.Xia@intel.com>
> Cc: stable@dpdk.org
> Subject: RE: [PATCH v2] vhost: fix assuming packed ring size is a power of 2
>
> Hi Maxime,
>
> I have also noticed the wrong calculation here, thanks for the timely help.
>
> Thanks,
> Cheng
>
> > -----Original Message-----
> > From: Maxime Coquelin <maxime.coquelin@redhat.com>
> > Sent: Wednesday, July 7, 2021 6:30 PM
> > To: dev@dpdk.org; Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> > <chenbo.xia@intel.com>
> > Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
> > Subject: [PATCH v2] vhost: fix assuming packed ring size is a power of
> > 2
> >
> > Unlike split ring, packed ring does not mandate the ring size to be a
> > power of 2. So we have to use a modulo operation when wrapping ring
> index.
> >
> > Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> > ---
> >
> > V2: Also fix wrapping in virtio_dev_rx_async_get_info_idx which is
> > used in the packed ring data path.
> >
> > lib/vhost/virtio_net.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
> > b93482587c..0de5231db7 100644
> > --- a/lib/vhost/virtio_net.c
> > +++ b/lib/vhost/virtio_net.c
> > @@ -1470,7 +1470,7 @@ virtio_dev_rx_async_get_info_idx(uint16_t
> > pkts_idx,
> > uint16_t vq_size, uint16_t n_inflight) {
> > return pkts_idx > n_inflight ? (pkts_idx - n_inflight) :
> > - (vq_size - n_inflight + pkts_idx) & (vq_size - 1);
> > + (vq_size - n_inflight + pkts_idx) % vq_size;
> > }
> >
> > static __rte_always_inline void
> > @@ -2131,7 +2131,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int
> > vid, uint16_t queue_id,
> >
> > if (vq_is_packed(dev)) {
> > for (i = 0; i < n_pkts_put; i++) {
> > - from = (start_idx + i) & (vq_size - 1);
> > + from = (start_idx + i) % vq_size;
> > n_buffers += pkts_info[from].nr_buffers;
> > pkts[i] = pkts_info[from].mbuf;
> > }
> > --
> > 2.31.1
>
>
> Acked-by: Cheng Jiang <cheng1.jiang@intel.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
2021-07-12 6:53 ` Jiang, Cheng1
@ 2021-07-12 9:16 ` Maxime Coquelin
0 siblings, 0 replies; 6+ messages in thread
From: Maxime Coquelin @ 2021-07-12 9:16 UTC (permalink / raw)
To: Jiang, Cheng1, dev, Xia, Chenbo; +Cc: stable
Hi Cheng,
Thanks for catching the issue.
It was an accident, that I thought I had resolved already :)
This is fixed now.
Maxime
On 7/12/21 8:53 AM, Jiang, Cheng1 wrote:
> Hi Maxime,
>
> I have noticed you changed the state this patch to Superseded.
> So are you going to submit a new version of this patch?
>
> Thanks,
> Cheng
>
>> -----Original Message-----
>> From: Jiang, Cheng1
>> Sent: Wednesday, July 7, 2021 7:11 PM
>> To: Maxime Coquelin <maxime.coquelin@redhat.com>; dev@dpdk.org; Xia,
>> Chenbo <Chenbo.Xia@intel.com>
>> Cc: stable@dpdk.org
>> Subject: RE: [PATCH v2] vhost: fix assuming packed ring size is a power of 2
>>
>> Hi Maxime,
>>
>> I have also noticed the wrong calculation here, thanks for the timely help.
>>
>> Thanks,
>> Cheng
>>
>>> -----Original Message-----
>>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>>> Sent: Wednesday, July 7, 2021 6:30 PM
>>> To: dev@dpdk.org; Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
>>> <chenbo.xia@intel.com>
>>> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
>>> Subject: [PATCH v2] vhost: fix assuming packed ring size is a power of
>>> 2
>>>
>>> Unlike split ring, packed ring does not mandate the ring size to be a
>>> power of 2. So we have to use a modulo operation when wrapping ring
>> index.
>>>
>>> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>> ---
>>>
>>> V2: Also fix wrapping in virtio_dev_rx_async_get_info_idx which is
>>> used in the packed ring data path.
>>>
>>> lib/vhost/virtio_net.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
>>> b93482587c..0de5231db7 100644
>>> --- a/lib/vhost/virtio_net.c
>>> +++ b/lib/vhost/virtio_net.c
>>> @@ -1470,7 +1470,7 @@ virtio_dev_rx_async_get_info_idx(uint16_t
>>> pkts_idx,
>>> uint16_t vq_size, uint16_t n_inflight) {
>>> return pkts_idx > n_inflight ? (pkts_idx - n_inflight) :
>>> - (vq_size - n_inflight + pkts_idx) & (vq_size - 1);
>>> + (vq_size - n_inflight + pkts_idx) % vq_size;
>>> }
>>>
>>> static __rte_always_inline void
>>> @@ -2131,7 +2131,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int
>>> vid, uint16_t queue_id,
>>>
>>> if (vq_is_packed(dev)) {
>>> for (i = 0; i < n_pkts_put; i++) {
>>> - from = (start_idx + i) & (vq_size - 1);
>>> + from = (start_idx + i) % vq_size;
>>> n_buffers += pkts_info[from].nr_buffers;
>>> pkts[i] = pkts_info[from].mbuf;
>>> }
>>> --
>>> 2.31.1
>>
>>
>> Acked-by: Cheng Jiang <cheng1.jiang@intel.com>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
2021-07-07 10:30 [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2 Maxime Coquelin
2021-07-07 11:11 ` Jiang, Cheng1
@ 2021-07-14 5:16 ` Xia, Chenbo
2021-07-20 2:51 ` Xia, Chenbo
2 siblings, 0 replies; 6+ messages in thread
From: Xia, Chenbo @ 2021-07-14 5:16 UTC (permalink / raw)
To: Maxime Coquelin, dev, Jiang, Cheng1; +Cc: stable
> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, July 7, 2021 6:30 PM
> To: dev@dpdk.org; Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> <chenbo.xia@intel.com>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
> Subject: [PATCH v2] vhost: fix assuming packed ring size is a power of 2
>
> Unlike split ring, packed ring does not mandate the ring size
> to be a power of 2. So we have to use a modulo operation when
> wrapping ring index.
>
> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> Cc: stable@dpdk.org
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>
> V2: Also fix wrapping in virtio_dev_rx_async_get_info_idx which is used
> in the packed ring data path.
>
> lib/vhost/virtio_net.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index b93482587c..0de5231db7 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1470,7 +1470,7 @@ virtio_dev_rx_async_get_info_idx(uint16_t pkts_idx,
> uint16_t vq_size, uint16_t n_inflight)
> {
> return pkts_idx > n_inflight ? (pkts_idx - n_inflight) :
> - (vq_size - n_inflight + pkts_idx) & (vq_size - 1);
> + (vq_size - n_inflight + pkts_idx) % vq_size;
> }
>
> static __rte_always_inline void
> @@ -2131,7 +2131,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid,
> uint16_t queue_id,
>
> if (vq_is_packed(dev)) {
> for (i = 0; i < n_pkts_put; i++) {
> - from = (start_idx + i) & (vq_size - 1);
> + from = (start_idx + i) % vq_size;
> n_buffers += pkts_info[from].nr_buffers;
> pkts[i] = pkts_info[from].mbuf;
> }
> --
> 2.31.1
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
2021-07-07 10:30 [dpdk-dev] [PATCH v2] vhost: fix assuming packed ring size is a power of 2 Maxime Coquelin
2021-07-07 11:11 ` Jiang, Cheng1
2021-07-14 5:16 ` Xia, Chenbo
@ 2021-07-20 2:51 ` Xia, Chenbo
2 siblings, 0 replies; 6+ messages in thread
From: Xia, Chenbo @ 2021-07-20 2:51 UTC (permalink / raw)
To: Maxime Coquelin, dev, Jiang, Cheng1; +Cc: stable
> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, July 7, 2021 6:30 PM
> To: dev@dpdk.org; Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> <chenbo.xia@intel.com>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
> Subject: [PATCH v2] vhost: fix assuming packed ring size is a power of 2
>
> Unlike split ring, packed ring does not mandate the ring size
> to be a power of 2. So we have to use a modulo operation when
> wrapping ring index.
>
> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> Cc: stable@dpdk.org
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>
> V2: Also fix wrapping in virtio_dev_rx_async_get_info_idx which is used
> in the packed ring data path.
>
> lib/vhost/virtio_net.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index b93482587c..0de5231db7 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1470,7 +1470,7 @@ virtio_dev_rx_async_get_info_idx(uint16_t pkts_idx,
> uint16_t vq_size, uint16_t n_inflight)
> {
> return pkts_idx > n_inflight ? (pkts_idx - n_inflight) :
> - (vq_size - n_inflight + pkts_idx) & (vq_size - 1);
> + (vq_size - n_inflight + pkts_idx) % vq_size;
> }
>
> static __rte_always_inline void
> @@ -2131,7 +2131,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid,
> uint16_t queue_id,
>
> if (vq_is_packed(dev)) {
> for (i = 0; i < n_pkts_put; i++) {
> - from = (start_idx + i) & (vq_size - 1);
> + from = (start_idx + i) % vq_size;
> n_buffers += pkts_info[from].nr_buffers;
> pkts[i] = pkts_info[from].mbuf;
> }
> --
> 2.31.1
Applied to next-virtio/main, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread