[dpdk-stable] [PATCH v2] vhost: fix assuming packed ring size is a power of 2

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* [dpdk-stable] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
@ 2021-07-07 10:30 Maxime Coquelin
  2021-07-07 11:11 ` Jiang, Cheng1
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Maxime Coquelin @ 2021-07-07 10:30 UTC (permalink / raw)
  To: dev, cheng1.jiang, chenbo.xia; +Cc: Maxime Coquelin, stable

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


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [dpdk-stable] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
  2021-07-07 10:30 [dpdk-stable] [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-stable] [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-stable] [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-stable] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
  2021-07-07 10:30 [dpdk-stable] [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-stable] [PATCH v2] vhost: fix assuming packed ring size is a power of 2
  2021-07-07 10:30 [dpdk-stable] [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

end of thread, other threads:[~2021-07-20  2:51 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-07 10:30 [dpdk-stable] [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
2021-07-12  9:16     ` Maxime Coquelin
2021-07-14  5:16 ` Xia, Chenbo
2021-07-20  2:51 ` Xia, Chenbo

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