From: Stephen Hemminger <stephen@networkplumber.org>
To: "Xie, Huawei" <huawei.xie@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] virtio: fix used ring address calculation
Date: Fri, 25 Sep 2015 10:48:10 -0700 [thread overview]
Message-ID: <20150925104810.2b0f0183@urahara> (raw)
In-Reply-To: <C37D651A908B024F974696C65296B57B40F33434@SHSMSX101.ccr.corp.intel.com>
On Fri, 25 Sep 2015 15:46:34 +0000
"Xie, Huawei" <huawei.xie@intel.com> wrote:
> On 9/25/2015 5:01 AM, Stephen Hemminger wrote:
> > On Thu, 24 Sep 2015 18:35:37 +0000
> > "Xie, Huawei" <huawei.xie@intel.com> wrote:
> >
> >> On 9/25/2015 12:36 AM, Stephen Hemminger wrote:
> >>> On Thu, 24 Sep 2015 07:30:41 +0000
> >>> "Xie, Huawei" <huawei.xie@intel.com> wrote:
> >>>
> >>>> On 9/21/2015 11:39 AM, Xie, Huawei wrote:
> >>>> vring_size calculation should consider both used_event_idx at the tail
> >>>> of avail ring and avail_event_idx at the tail of used ring.
> >>>> Will merge those two fixes and send a new patch.
> >>>>> used event idx is put at the end of available ring. It isn't taken into account
> >>>>> when we calculate the address of used ring. Fortunately, it doesn't introduce
> >>>>> the bug with fixed queue number 256 and 4KB alignment.
> >>>>>
> >>>>> Signed-off-by: hxie5 <huawei.xie@intel.com>
> >>>>> ---
> >>>>> drivers/net/virtio/virtio_ring.h | 2 +-
> >>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>>
> >>>>> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
> >>>>> index a16c499..92e430d 100644
> >>>>> --- a/drivers/net/virtio/virtio_ring.h
> >>>>> +++ b/drivers/net/virtio/virtio_ring.h
> >>>>> @@ -145,7 +145,7 @@ vring_init(struct vring *vr, unsigned int num, uint8_t *p,
> >>>>> vr->avail = (struct vring_avail *) (p +
> >>>>> num * sizeof(struct vring_desc));
> >>>>> vr->used = (void *)
> >>>>> - RTE_ALIGN_CEIL((uintptr_t)(&vr->avail->ring[num]), align);
> >>>>> + RTE_ALIGN_CEIL((uintptr_t)(&vr->avail->ring[num + 1]), align);
> >>>>> }
> >>>>>
> >>>>> /*
> >>> Why aren't we just using the standard Linux includes for this?
> >>> See <linux/virtio_ring.h> and the function vring_init()
> >>>
> >>> Keeping parallel copies of headers is prone to failures.
> >> Agree.
> >> Using standard Linux includes then at least we don't need to redefine
> >> the feature and other related MACRO.
> >> This applies to vhost as well.
> >> For vring, vring_init, we could also reuse the linux implementation
> >> unless we have strong reason to define our own structure.
> >> One reason was to support both FreeBSD and Linux. FreeBSD should have
> >> its own header file. To avoid the case they have different vring
> >> structure or VIRTIO_F_xx macro name, they are redefined here.
> >>
> > The Linux headers for virtio are explictly BSD licensed.
> > You could at least just have a local copy of same code.
> >
> Exactly the same code (if no dependency and no other issue) or copy and
> convert it to DPDK style? By DPDK style, i mean like using RTE_ALIGN macro.
No. keep the Linux code as is. Just copy the headers.
Don't introduce DPDK style.
prev parent reply other threads:[~2015-09-25 17:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-21 3:39 Huawei Xie
2015-09-21 9:19 ` Tan, Jianfeng
2015-09-24 7:30 ` Xie, Huawei
2015-09-24 16:36 ` Stephen Hemminger
2015-09-24 18:35 ` Xie, Huawei
2015-09-24 21:01 ` Stephen Hemminger
2015-09-25 15:46 ` Xie, Huawei
2015-09-25 17:48 ` Stephen Hemminger [this message]
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