mirror of
https://github.com/xen-project/xen.git
synced 2026-10-28 10:11:27 +01:00
Keir Fraser
bd5573a630
Benefits to blktap2 over the old version of blktap: * Isolation from xenstore - Blktap devices are now created directly on the linux dom0 command line, rather than being spawned in response to XenStore events. This is handy for debugging, makes blktap generally easier to work with, and is a step toward a generic user-level block device implementation that is not Xen-specific. * Improved tapdisk infrastructure: simpler request forwarding, new request scheduler, request merging, more efficient use of AIO. * Improved tapdisk error handling and memory management. No allocations on the block data path, IO retry logic to protect guests transient block device failures. This has been tested and is known to work on weird environments such as NFS soft mounts. * Pause and snapshot of live virtual disks (see xmsnap script). * VHD support. The VHD code in this release has been rigorously tested, and represents a very mature implementation of the VHD image format. * No more duplication of mechanism with blkback. The blktap kernel module has changed dramatically from the original blktap. Blkback is now always used to talk to Xen guests, blktap just presents a Linux gendisk that blkback can export. This is done while preserving the zero-copy data path from domU to physical device. These patches deprecate the old blktap code, which can hopefully be removed from the tree completely at some point in the future. Signed-off-by: Jake Wires <jake.wires@citrix.com> Signed-off-by: Dutch Meyer <dmeyer@cs.ubc.ca>
34 lines
1.6 KiB
C
34 lines
1.6 KiB
C
/* $OpenBSD: atomicio.h,v 1.6 2005/05/24 17:32:43 avsm Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1995,1999 Theo de Raadt. All rights reserved.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
* Ensure all of data on socket comes through. f==read || f==vwrite
|
|
*/
|
|
size_t atomicio(ssize_t (*)(int, void *, size_t), int, void *, size_t);
|
|
|
|
#define vwrite (ssize_t (*)(int, void *, size_t))write
|