/*
 * MDEV driver
 *
 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
 *     Author: Neo Jia <cjia@nvidia.com>
 *             Kirti Wankhede <kwankhede@nvidia.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/iommu.h>
#include <linux/mdev.h>

#include "mdev_private.h"

static int mdev_attach_iommu(struct mdev_device *mdev)
{
	int ret;
	struct iommu_group *group;

	group = iommu_group_alloc();
	if (IS_ERR(group))
		return PTR_ERR(group);

	ret = iommu_group_add_device(group, &mdev->dev);
	if (!ret)
		dev_info(&mdev->dev, "MDEV: group_id = %d\n",
			 iommu_group_id(group));

	iommu_group_put(group);
	return ret;
}

static void mdev_detach_iommu(struct mdev_device *mdev)
{
	iommu_group_remove_device(&mdev->dev);
	dev_info(&mdev->dev, "MDEV: detaching iommu\n");
}

static int mdev_probe(struct device *dev)
{
	struct mdev_driver *drv = to_mdev_driver(dev->driver);
	struct mdev_device *mdev = to_mdev_device(dev);
	int ret;

	ret = mdev_attach_iommu(mdev);
	if (ret)
		return ret;

	if (drv && drv->probe) {
		ret = drv->probe(dev);
		if (ret)
			mdev_detach_iommu(mdev);
	}

	return ret;
}

static int mdev_remove(struct device *dev)
{
	struct mdev_driver *drv = to_mdev_driver(dev->driver);
	struct mdev_device *mdev = to_mdev_device(dev);

	if (drv && drv->remove)
		drv->remove(dev);

	mdev_detach_iommu(mdev);

	return 0;
}

struct bus_type mdev_bus_type = {
	.name		= "mdev",
	.probe		= mdev_probe,
	.remove		= mdev_remove,
};
EXPORT_SYMBOL_GPL(mdev_bus_type);

/**
 * mdev_register_driver - register a new MDEV driver
 * @drv: the driver to register
 * @owner: module owner of driver to be registered
 *
 * Returns a negative value on error, otherwise 0.
 **/
int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
{
	/* initialize common driver fields */
	drv->driver.name = drv->name;
	drv->driver.bus = &mdev_bus_type;
	drv->driver.owner = owner;

	/* register with core */
	return driver_register(&drv->driver);
}
EXPORT_SYMBOL(mdev_register_driver);

/*
 * mdev_unregister_driver - unregister MDEV driver
 * @drv: the driver to unregister
 */
void mdev_unregister_driver(struct mdev_driver *drv)
{
	driver_unregister(&drv->driver);
}
EXPORT_SYMBOL(mdev_unregister_driver);

int mdev_bus_register(void)
{
	return bus_register(&mdev_bus_type);
}

void mdev_bus_unregister(void)
{
	bus_unregister(&mdev_bus_type);
}
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?h=nds-private-remove&amp;id=d983001f044cf823490af7dcfcde39cfb42be0db'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/net?h=nds-private-remove&amp;id=d983001f044cf823490af7dcfcde39cfb42be0db'>net</a>/<a href='/cgit.cgi/linux/net-next.git/log/net/xfrm?h=nds-private-remove&amp;id=d983001f044cf823490af7dcfcde39cfb42be0db'>xfrm</a>/<a href='/cgit.cgi/linux/net-next.git/log/net/xfrm/xfrm_output.c?h=nds-private-remove&amp;id=d983001f044cf823490af7dcfcde39cfb42be0db'>xfrm_output.c</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/net/xfrm/xfrm_output.c?h=nds-private-remove&amp;id=d983001f044cf823490af7dcfcde39cfb42be0db&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Dexuan Cui &lt;decui@microsoft.com&gt;</td><td class='right'>2017-01-28 11:46:02 -0700</td></tr>
<tr><th>committer</th><td>Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;</td><td class='right'>2017-01-31 10:59:48 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/net/llc_s_st.h?id=433e19cf33d34bb6751c874a9c00980552fe508c'>433e19cf33d34bb6751c874a9c00980552fe508c</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/net/llc_s_st.h?id=433e19cf33d34bb6751c874a9c00980552fe508c'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=433e19cf33d34bb6751c874a9c00980552fe508c'>ce6547ef2987fbb289fa28f03536328a42781651</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/net/llc_s_st.h?id=433e19cf33d34bb6751c874a9c00980552fe508c'>include/net/llc_s_st.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/net/llc_s_st.h?id=191e885a2e130e639bb0c8ee350d7047294f2ce6'>191e885a2e130e639bb0c8ee350d7047294f2ce6</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/net/llc_s_st.h?id=433e19cf33d34bb6751c874a9c00980552fe508c&amp;id2=191e885a2e130e639bb0c8ee350d7047294f2ce6'>diff</a>)</td></tr></table>
<div class='commit-subject'>Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()</div><div class='commit-msg'>Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz &lt; pending_sz"
when making the signal decision.

As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.

This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).

Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")

Signed-off-by: Dexuan Cui &lt;decui@microsoft.com&gt;
Reported-by: Rolf Neugebauer &lt;rolf.neugebauer@docker.com&gt;
Tested-by: Rolf Neugebauer &lt;rolf.neugebauer@docker.com&gt;
Cc: "K. Y. Srinivasan" &lt;kys@microsoft.com&gt;
Cc: Haiyang Zhang &lt;haiyangz@microsoft.com&gt;
Cc: Stephen Hemminger &lt;sthemmin@microsoft.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: K. Y. Srinivasan &lt;kys@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=433e19cf33d34bb6751c874a9c00980552fe508c'>Diffstat</a> (limited to 'include/net/llc_s_st.h')</div><table summary='diffstat' class='diffstat'>