/*
 * uio_hv_generic - generic UIO driver for VMBus
 *
 * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
 * Copyright (c) 2016, Microsoft Corporation.
 *
 *
 * This work is licensed under the terms of the GNU GPL, version 2.
 *
 * Since the driver does not declare any device ids, you must allocate
 * id and bind the device to the driver yourself.  For example:
 *
 * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
 *    > /sys/bus/vmbus/drivers/uio_hv_generic
 * # echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 \
 *    > /sys/bus/vmbus/drivers/hv_netvsc/unbind
 * # echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 \
 *    > /sys/bus/vmbus/drivers/uio_hv_generic/bind
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uio_driver.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/hyperv.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>

#include "../hv/hyperv_vmbus.h"

#define DRIVER_VERSION	"0.02.0"
#define DRIVER_AUTHOR	"Stephen Hemminger <sthemmin at microsoft.com>"
#define DRIVER_DESC	"Generic UIO driver for VMBus devices"

/*
 * List of resources to be mapped to user space
 * can be extended up to MAX_UIO_MAPS(5) items
 */
enum hv_uio_map {
	TXRX_RING_MAP = 0,
	INT_PAGE_MAP,
	MON_PAGE_MAP,
};

#define HV_RING_SIZE	512

struct hv_uio_private_data {
	struct uio_info info;
	struct hv_device *device;
};

static int
hv_uio_mmap(struct uio_info *info, struct vm_area_struct *vma)
{
	int mi;

	if (vma->vm_pgoff >= MAX_UIO_MAPS)
		return -EINVAL;

	if (info->mem[vma->vm_pgoff].size == 0)
		return -EINVAL;

	mi = (int)vma->vm_pgoff;

	return remap_pfn_range(vma, vma->vm_start,
			info->mem[mi].addr >> PAGE_SHIFT,
			vma->vm_end - vma->vm_start, vma->vm_page_prot);
}

/*
 * This is the irqcontrol callback to be registered to uio_info.
 * It can be used to disable/enable interrupt from user space processes.
 *
 * @param info
 *  pointer to uio_info.
 * @param irq_state
 *  state value. 1 to enable interrupt, 0 to disable interrupt.
 */
static int
hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
{
	struct hv_uio_private_data *pdata = info->priv;
	struct hv_device *dev = pdata->device;

	dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
	virt_mb();

	return 0;
}

/*
 * Callback from vmbus_event when something is in inbound ring.
 */
static void hv_uio_channel_cb(void *context)
{
	struct hv_uio_private_data *pdata = context;
	struct hv_device *dev = pdata->device;

	dev->channel->inbound.ring_buffer->interrupt_mask = 1;
	virt_mb();

	uio_event_notify(&pdata->info);
}

static int
hv_uio_probe(struct hv_device *dev,
	     const struct hv_vmbus_device_id *dev_id)
{
	struct hv_uio_private_data *pdata;
	int ret;

	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;

	ret = vmbus_open(dev->channel, HV_RING_SIZE * PAGE_SIZE,
			 HV_RING_SIZE * PAGE_SIZE, NULL, 0,
			 hv_uio_channel_cb, pdata);
	if (ret)
		goto fail;

	dev->channel->inbound.ring_buffer->interrupt_mask = 1;
	dev->channel->batched_reading = false;

	/* Fill general uio info */
	pdata->info.name = "uio_hv_generic";
	pdata->info.version = DRIVER_VERSION;
	pdata->info.irqcontrol = hv_uio_irqcontrol;
	pdata->info.mmap = hv_uio_mmap;
	pdata->info.irq = UIO_IRQ_CUSTOM;

	/* mem resources */
	pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
	pdata->info.mem[TXRX_RING_MAP].addr
		= virt_to_phys(dev->channel->ringbuffer_pages);
	pdata->info.mem[TXRX_RING_MAP].size
		= dev->channel->ringbuffer_pagecount * PAGE_SIZE;
	pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_LOGICAL;

	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
	pdata->info.mem[INT_PAGE_MAP].addr =
		virt_to_phys(vmbus_connection.int_page);
	pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
	pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;

	pdata->info.mem[MON_PAGE_MAP].name = "monitor_pages";
	pdata->info.mem[MON_PAGE_MAP].addr =
		virt_to_phys(vmbus_connection.monitor_pages[1]);
	pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;

	pdata->info.priv = pdata;
	pdata->device = dev;

	ret = uio_register_device(&dev->device, &pdata->info);
	if (ret) {
		dev_err(&dev->device, "hv_uio register failed\n");
		goto fail_close;
	}

	hv_set_drvdata(dev, pdata);

	return 0;

fail_close:
	vmbus_close(dev->channel);
fail:
	kfree(pdata);

	return ret;
}

static int
hv_uio_remove(struct hv_device *dev)
{
	struct hv_uio_private_data *pdata = hv_get_drvdata(dev);

	if (!pdata)
		return 0;

	uio_unregister_device(&pdata->info);
	hv_set_drvdata(dev, NULL);
	vmbus_close(dev->channel);
	kfree(pdata);
	return 0;
}

static struct hv_driver hv_uio_drv = {
	.name = "uio_hv_generic",
	.id_table = NULL, /* only dynamic id's */
	.probe = hv_uio_probe,
	.remove = hv_uio_remove,
};

static int __init
hyperv_module_init(void)
{
	return vmbus_driver_register(&hv_uio_drv);
}

static void __exit
hyperv_module_exit(void)
{
	vmbus_driver_unregister(&hv_uio_drv);
}

module_init(hyperv_module_init);
module_exit(hyperv_module_exit);

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
f='/cgit.cgi/linux/net-next.git/tree/fs/xfs/xfs_sysctl.h?id=e0d76fa4475ef2cf4b52d18588b8ce95153d021b'>fs/xfs/xfs_sysctl.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/fs/xfs/xfs_sysctl.h?id=c364b6d0b6cda1cd5d9ab689489adda3e82529aa'>c364b6d0b6cda1cd5d9ab689489adda3e82529aa</a> (<a href='/cgit.cgi/linux/net-next.git/diff/fs/xfs/xfs_sysctl.h?id=e0d76fa4475ef2cf4b52d18588b8ce95153d021b&amp;id2=c364b6d0b6cda1cd5d9ab689489adda3e82529aa'>diff</a>)</td></tr></table>
<div class='commit-subject'>xfs: prevent quotacheck from overloading inode lru</div><div class='commit-msg'>Quotacheck runs at mount time in situations where quota accounting must
be recalculated. In doing so, it uses bulkstat to visit every inode in
the filesystem. Historically, every inode processed during quotacheck
was released and immediately tagged for reclaim because quotacheck runs
before the superblock is marked active by the VFS. In other words,
the final iput() lead to an immediate -&gt;destroy_inode() call, which
allowed the XFS background reclaim worker to start reclaiming inodes.

Commit 17c12bcd3 ("xfs: when replaying bmap operations, don't let
unlinked inodes get reaped") marks the XFS superblock active sooner as
part of the mount process to support caching inodes processed during log
recovery. This occurs before quotacheck and thus means all inodes
processed by quotacheck are inserted to the LRU on release.  The
s_umount lock is held until the mount has completed and thus prevents
the shrinkers from operating on the sb. This means that quotacheck can
excessively populate the inode LRU and lead to OOM conditions on systems
without sufficient RAM.

Update the quotacheck bulkstat handler to set XFS_IGET_DONTCACHE on
inodes processed by quotacheck. This causes -&gt;drop_inode() to return 1
and in turn causes iput_final() to evict the inode. This preserves the
original quotacheck behavior and prevents it from overloading the LRU
and running out of memory.

CC: stable@vger.kernel.org # v4.9
Reported-by: Martin Svec &lt;martin.svec@zoner.cz&gt;
Signed-off-by: Brian Foster &lt;bfoster@redhat.com&gt;
Reviewed-by: Eric Sandeen &lt;sandeen@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=e0d76fa4475ef2cf4b52d18588b8ce95153d021b'>Diffstat</a> (limited to 'fs/xfs/xfs_sysctl.h')</div><table summary='diffstat' class='diffstat'>