From: Paolo Bonzini <pbonzini@redhat.com>
To: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 5/5] virtio-blk: Drop VirtIOBlockReq.read
Date: Wed, 04 Jun 2014 10:42:04 +0200 [thread overview]
Message-ID: <538EDBDC.2060701@redhat.com> (raw)
In-Reply-To: <20140604075354.GC3223@T430.nay.redhat.com>
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.
Paolo
next prev parent reply other threads:[~2014-06-04 8:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-03 12:52 [Qemu-devel] [PATCH 0/5] virtio-blk: Converge VirtIOBlockRequest into VirtIOBlockReq Fam Zheng
2014-06-03 12:52 ` [Qemu-devel] [PATCH 1/5] virtio-blk: Move VirtIOBlockReq to header Fam Zheng
2014-06-03 12:52 ` [Qemu-devel] [PATCH 2/5] virtio-blk: Convert VirtIOBlockReq.elem to pointer Fam Zheng
2014-06-03 12:52 ` [Qemu-devel] [PATCH 3/5] virtio-blk: Merge VirtIOBlockRequest into VirtIOBlockReq Fam Zheng
2014-06-03 12:52 ` [Qemu-devel] [PATCH 4/5] virtio-blk: Drop bounce buffer from dataplane code Fam Zheng
2014-06-03 13:28 ` Paolo Bonzini
2014-06-03 12:52 ` [Qemu-devel] [PATCH 5/5] virtio-blk: Drop VirtIOBlockReq.read Fam Zheng
2014-06-03 13:37 ` Paolo Bonzini
2014-06-04 7:10 ` Fam Zheng
2014-06-04 7:53 ` Fam Zheng
2014-06-04 8:42 ` Paolo Bonzini [this message]
2014-06-04 11:03 ` Fam Zheng
2014-06-04 11:10 ` Paolo Bonzini
2014-06-04 9:28 ` Stefan Hajnoczi
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