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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Wanlong Gao <gaowanlong@cn.fujitsu.com>,
	asias@redhat.com, Rusty Russell <rusty@rustcorp.com.au>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 1/9] virtio: add functions for piecewise addition of buffers
Date: Tue, 12 Feb 2013 16:32:27 +0100	[thread overview]
Message-ID: <511A608B.5080007@redhat.com> (raw)
In-Reply-To: <20130212145620.GA3392@redhat.com>

Il 12/02/2013 15:56, Michael S. Tsirkin ha scritto:
>> > +/**
>> > + * virtqueue_start_buf - start building buffer for the other end
>> > + * @vq: the struct virtqueue we're talking about.
>> > + * @data: the token identifying the buffer.
>> > + * @nents: the number of buffers that will be added
> This function starts building one buffer, number of buffers
> is a bit weird here.

Ok.

>> > + * @nsg: the number of sg lists that will be added
> This means number of calls to add_sg ? Not sure why this matters.
> How about we pass in in_num/out_num - that is total # of sg,
> same as add_buf?

It is used to choose between direct and indirect.

>> > +/**
>> > + * virtqueue_add_sg - add sglist to buffer being built
>> > + * @_vq: the virtqueue for which the buffer is being built
>> > + * @sgl: the description of the buffer(s).
>> > + * @nents: the number of items to process in sgl
>> > + * @dir: whether the sgl is read or written (DMA_TO_DEVICE/DMA_FROM_DEVICE only)
>> > + *
>> > + * Note that, unlike virtqueue_add_buf, this function follows chained
>> > + * scatterlists, and stops before the @nents-th item if a scatterlist item
>> > + * has a marker.
>> > + *
>> > + * Caller must ensure we don't call this with other virtqueue operations
>> > + * at the same time (except where noted).
> Hmm so if you want to add in and out, need separate calls?
> in_num/out_num would be nicer?

If you want to add in and out just use virtqueue_add_buf...

Paolo


  reply	other threads:[~2013-02-12 15:32 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-12 12:23 [PATCH 0/9] virtio: new API for addition of buffers, scatterlist changes Paolo Bonzini
2013-02-12 12:23 ` [PATCH 1/9] virtio: add functions for piecewise addition of buffers Paolo Bonzini
2013-02-12 14:56   ` Michael S. Tsirkin
2013-02-12 15:32     ` Paolo Bonzini [this message]
2013-02-12 15:43       ` Michael S. Tsirkin
2013-02-12 15:48         ` Paolo Bonzini
2013-02-12 16:13           ` Michael S. Tsirkin
2013-02-12 16:17             ` Paolo Bonzini
2013-02-12 16:35               ` Michael S. Tsirkin
2013-02-12 16:57                 ` Paolo Bonzini
2013-02-12 17:34                   ` Michael S. Tsirkin
2013-02-12 18:04                     ` Paolo Bonzini
2013-02-12 18:23                       ` Michael S. Tsirkin
2013-02-12 20:08                         ` Paolo Bonzini
2013-02-12 20:49                           ` Michael S. Tsirkin
2013-02-13  8:06                             ` Paolo Bonzini
2013-02-13 10:33                               ` Michael S. Tsirkin
2013-02-12 18:03   ` [PATCH v2 " Paolo Bonzini
2013-02-12 12:23 ` [PATCH 2/9] virtio-blk: reorganize virtblk_add_req Paolo Bonzini
2013-02-17  6:38   ` Asias He
2013-02-12 12:23 ` [PATCH 3/9] virtio-blk: use virtqueue_start_buf on bio path Paolo Bonzini
2013-02-17  6:39   ` Asias He
2013-02-12 12:23 ` [PATCH 4/9] virtio-blk: use virtqueue_start_buf on req path Paolo Bonzini
2013-02-17  6:37   ` Asias He
2013-02-18  9:05     ` Paolo Bonzini
2013-02-12 12:23 ` [PATCH 5/9] scatterlist: introduce sg_unmark_end Paolo Bonzini
2013-02-12 12:23 ` [PATCH 6/9] virtio-net: unmark scatterlist ending after virtqueue_add_buf Paolo Bonzini
2013-02-12 12:23 ` [PATCH 7/9] virtio-scsi: use virtqueue_start_buf Paolo Bonzini
2013-02-12 12:23 ` [PATCH 8/9] virtio: introduce and use virtqueue_add_buf_single Paolo Bonzini
2013-02-12 12:23 ` [PATCH 9/9] virtio: reimplement virtqueue_add_buf using new functions Paolo Bonzini
2013-02-14  6:00 ` [PATCH 0/9] virtio: new API for addition of buffers, scatterlist changes Rusty Russell
2013-02-14  9:23   ` Paolo Bonzini
2013-02-15 18:04     ` Paolo Bonzini
2013-02-19  7:49     ` Rusty Russell
2013-02-19  9:11       ` Paolo Bonzini

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