From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"olivier.matz@6wind.com" <olivier.matz@6wind.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH] net/virtio-user: fix not working on 32-bit system
Date: Fri, 14 Apr 2017 14:20:17 +0800 [thread overview]
Message-ID: <20170414062017.GM7333@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <ED26CBA2FAD1BF48A8719AEF02201E365119F5FB@SHSMSX103.ccr.corp.intel.com>
On Fri, Apr 14, 2017 at 05:53:55AM +0000, Tan, Jianfeng wrote:
> > > diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> > > index f9e3736..f43ea70 100644
> > > --- a/drivers/net/virtio/virtqueue.h
> > > +++ b/drivers/net/virtio/virtqueue.h
> > > @@ -72,7 +72,8 @@ struct rte_mbuf;
> > > * Return the physical address (or virtual address in case of
> > > * virtio-user) of mbuf data buffer.
> > > */
> > > -#define VIRTIO_MBUF_ADDR(mb, vq) (*(uint64_t *)((uintptr_t)(mb) +
> > (vq)->offset))
> > > +#define VIRTIO_MBUF_ADDR(mb, vq) \
> > > + ((uint64_t)((uintptr_t)(*(void **)((uintptr_t)(mb) + (vq)->offset))))
> >
> > The "void **" cast makes it a bit complex (thus hard to read). I think
> > following should work?
>
> Yes, uintptr_t can work. I thought void ** is easier to understand, meaning a convert to a pointer which pointing to a pointer.
It's twisted, isn't it? :)
> I usually use uintptr_t only for converter from pointer to integer, not the opposite way.
Yes, that's a typical usage. But the fact of the matter is uintptr_t
represents the word size, which is exactly what needed in this case.
--yliu
>
> >
> > (uint64_t(*(uintptr_t *)((uintptr_t)(mb) + (vq)->offset)))
> >
> > Besides, it deserves a comment.
>
> Will add comment in next version.
>
> Thanks,
> Jianfeng
>
> >
> > --yliu
> >
> > > #else
> > > #define VIRTIO_MBUF_ADDR(mb, vq) ((mb)->buf_physaddr)
> > > #endif
> > > --
> > > 2.7.4
next prev parent reply other threads:[~2017-04-14 6:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-13 14:12 Jianfeng Tan
2017-04-14 5:32 ` Yuanhan Liu
2017-04-14 5:53 ` Tan, Jianfeng
2017-04-14 6:20 ` Yuanhan Liu [this message]
2017-04-14 6:56 ` Tan, Jianfeng
2017-04-14 7:01 ` Yuanhan Liu
2017-04-14 7:14 ` Tan, Jianfeng
2017-04-19 2:30 ` [dpdk-stable] [PATCH v2] " Jianfeng Tan
2017-04-19 5:53 ` Yuanhan Liu
2017-04-19 6:21 ` Tan, Jianfeng
2017-04-19 6:24 ` Yuanhan Liu
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