26 messages in com.xensource.lists.xen-devel[Xen-devel] Re: [PATCH RFC 3/3] Virti...
FromSent OnAttachments
Rusty Russell07 Jun 2007 05:02 
Rusty Russell07 Jun 2007 05:04 
Rusty Russell07 Jun 2007 05:04 
Rusty Russell07 Jun 2007 05:06 
Avi Kivity07 Jun 2007 05:18 
Rusty Russell07 Jun 2007 18:11 
Rusty Russell16 Jun 2007 06:12 
Rusty Russell16 Jun 2007 06:14 
Rusty Russell16 Jun 2007 06:16 
Rusty Russell16 Jun 2007 06:18 
Rusty Russell16 Jun 2007 06:28 
Arnd Bergmann16 Jun 2007 06:50 
Avi Kivity17 Jun 2007 07:14 
Avi Kivity17 Jun 2007 07:24 
Rusty Russell18 Jun 2007 00:47 
Rusty Russell18 Jun 2007 01:07 
Avi Kivity18 Jun 2007 02:08 
Rusty Russell18 Jun 2007 23:27 
Avi Kivity19 Jun 2007 01:34 
Brian King25 Jun 2007 08:26 
Christoph Hellwig25 Jun 2007 12:32 
Avi Kivity25 Jun 2007 14:54 
Brian King25 Jun 2007 15:13 
Avi Kivity25 Jun 2007 15:19 
Rusty Russell28 Jun 2007 04:20 
Brian King28 Jun 2007 08:55 
Subject:[Xen-devel] Re: [PATCH RFC 3/3] Virtio draft III: example block driver
From:Avi Kivity (av@qumranet.com)
Date:06/17/2007 07:24:58 AM
List:com.xensource.lists.xen-devel

Rusty Russell wrote:

+static bool do_read(request_queue_t *q, struct virtio_blk *vblk, + struct virtblk_req *vbr) +{ + unsigned long num; + + vbr->out_hdr.type |= VIRTIO_BLK_T_READ; + + /* Set up for reply. */ + vblk->sg[0].page = virt_to_page(&vbr->in_hdr); + vblk->sg[0].offset = offset_in_page(&vbr->in_hdr); + vblk->sg[0].length = sizeof(vbr->in_hdr); + num = blk_rq_map_sg(q, vbr->req, vblk->sg+1); + vbr->out_hdr.id = vblk->vdev->ops->add_inbuf(vblk->vdev, vblk->sg, + 1+num, vbr); + if (IS_ERR_VALUE(vbr->out_hdr.id)) + goto full; + + vblk->sg[0].page = virt_to_page(&vbr->out_hdr); + vblk->sg[0].offset = offset_in_page(&vbr->out_hdr); + vblk->sg[0].length = sizeof(vbr->out_hdr); + + vbr->out_id = vblk->vdev->ops->add_outbuf(vblk->vdev, vblk->sg, 1, + vbr);

This strikes me as wasteful. Why not set up a single descriptor which contains both placement and the data itself?

-- error compiling committee.c: too many arguments to function

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