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Re: [Qemu-devel] [PATCH 5/5] virtio-blk: Drop VirtIOBlockReq.read
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH 5/5] virtio-blk: Drop VirtIOBlockReq.read |
Date: |
Wed, 4 Jun 2014 19:03:16 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, 06/04 10:42, Paolo Bonzini wrote:
> Il 04/06/2014 09:53, Fam Zheng ha scritto:
> >>> For the sake of restarting requests, we also need dataplane to populate
> >>> the
> >>> "out" field for dataplane. We can also take the occasion to change it
> >>> from
> >>> "struct virtio_blk_outhdr *" to "struct virtio_blk_outhdr" for
> >>> non-dataplane
> >>> and use iov_discard_front on the elem (see dataplane's process_request
> >>> function).
> >Using pointer avoids copying, what's the advantage of converting to "sturct
> >virtio_blk_outhdr" for non-dataplane code? For thread-safety?
>
> The virtio code currently assumes that the outhdr is in its own iovec. This
> is not guaranteed by the spec, it's just that the drivers do it because QEMU
> required it.
>
I see, thanks. Will convert it. IIUC, this also applies to inhdr? Do we need to
fix them as well?
Fam
- [Qemu-devel] [PATCH 1/5] virtio-blk: Move VirtIOBlockReq to header, (continued)
- [Qemu-devel] [PATCH 1/5] virtio-blk: Move VirtIOBlockReq to header, Fam Zheng, 2014/06/03
- [Qemu-devel] [PATCH 2/5] virtio-blk: Convert VirtIOBlockReq.elem to pointer, Fam Zheng, 2014/06/03
- [Qemu-devel] [PATCH 3/5] virtio-blk: Merge VirtIOBlockRequest into VirtIOBlockReq, Fam Zheng, 2014/06/03
- [Qemu-devel] [PATCH 4/5] virtio-blk: Drop bounce buffer from dataplane code, Fam Zheng, 2014/06/03
- [Qemu-devel] [PATCH 5/5] virtio-blk: Drop VirtIOBlockReq.read, Fam Zheng, 2014/06/03
- Re: [Qemu-devel] [PATCH 5/5] virtio-blk: Drop VirtIOBlockReq.read, Stefan Hajnoczi, 2014/06/04