/*
 * xfrm4_mode_transport.c - Transport mode encapsulation for IPv4.
 *
 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>

/* Add encapsulation header.
 *
 * The IP header will be moved forward to make space for the encapsulation
 * header.
 */
static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct iphdr *iph = ip_hdr(skb);
	int ihl = iph->ihl * 4;

	skb_set_network_header(skb, -x->props.header_len);
	skb->mac_header = skb->network_header +
			  offsetof(struct iphdr, protocol);
	skb->transport_header = skb->network_header + ihl;
	__skb_pull(skb, ihl);
	memmove(skb_network_header(skb), iph, ihl);
	return 0;
}

/* Remove encapsulation header.
 *
 * The IP header will be moved over the top of the encapsulation header.
 *
 * On entry, skb->h shall point to where the IP header should be and skb->nh
 * shall be set to where the IP header currently is.  skb->data shall point
 * to the start of the payload.
 */
static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int ihl = skb->data - skb_transport_header(skb);

	if (skb->transport_header != skb->network_header) {
		memmove(skb_transport_header(skb),
			skb_network_header(skb), ihl);
		skb->network_header = skb->transport_header;
	}
	ip_hdr(skb)->tot_len = htons(skb->len + ihl);
	skb_reset_transport_header(skb);
	return 0;
}

static struct xfrm_mode xfrm4_transport_mode = {
	.input = xfrm4_transport_input,
	.output = xfrm4_transport_output,
	.owner = THIS_MODULE,
	.encap = XFRM_MODE_TRANSPORT,
};

static int __init xfrm4_transport_init(void)
{
	return xfrm_register_mode(&xfrm4_transport_mode, AF_INET);
}

static void __exit xfrm4_transport_exit(void)
{
	int err;

	err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET);
	BUG_ON(err);
}

module_init(xfrm4_transport_init);
module_exit(xfrm4_transport_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT);
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>drivers</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>usb</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/usbip?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>usbip</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/usbip/Kconfig?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>Kconfig</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</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>Tony Lindgren &lt;tony@atomide.com&gt;</td><td class='right'>2017-01-19 08:49:07 -0800</td></tr>
<tr><th>committer</th><td>Vinod Koul &lt;vinod.koul@intel.com&gt;</td><td class='right'>2017-01-25 11:29:11 +0530</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/usbip/Kconfig?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/usbip/Kconfig?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>139fc7e29f97d6bb6c4dca2a97be2dc3f824bd51</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/usbip/Kconfig?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>drivers/usb/usbip/Kconfig</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/usbip/Kconfig?id=49def1853334396f948dcb4cedb9347abb318df5'>49def1853334396f948dcb4cedb9347abb318df5</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/usbip/Kconfig?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b&amp;id2=49def1853334396f948dcb4cedb9347abb318df5'>diff</a>)</td></tr></table>
<div class='commit-subject'>dmaengine: cppi41: Fix runtime PM timeouts with USB mass storage</div><div class='commit-msg'>Commit fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
added runtime PM support for cppi41, but had corner case issues. Some of
the issues were fixed with commit 098de42ad670 ("dmaengine: cppi41: Fix
unpaired pm runtime when only a USB hub is connected"). That fix however
caused a new regression where we can get error -115 messages with USB on
BeagleBone when connecting a USB mass storage device to a hub.

This is because when connecting a USB mass storage device to a hub, the
initial DMA transfers can take over 200ms to complete and cppi41
autosuspend delay times out.

To fix the issue, we want to implement refcounting for chan_busy array
that contains the active dma transfers. Increasing the autosuspend delay
won't help as that the delay could be potentially seconds, and it's best
to let the USB subsystem to deal with the timeouts on errors.

The earlier attempt for runtime PM was buggy as the pm_runtime_get/put()
calls could get unpaired easily as they did not follow the state of
the chan_busy array as described in commit 098de42ad670 ("dmaengine:
cppi41: Fix unpaired pm runtime when only a USB hub is connected".

Let's fix the issue by adding pm_runtime_get() to where a new transfer
is added to the chan_busy array, and calls to pm_runtime_put() where
chan_busy array entry is cleared. This prevents any autosuspend timeouts
from happening while dma transfers are active.

Fixes: 098de42ad670 ("dmaengine: cppi41: Fix unpaired pm runtime when
only a USB hub is connected")
Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
Cc: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Cc: Bin Liu &lt;b-liu@ti.com&gt;
Cc: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Cc: Kevin Hilman &lt;khilman@baylibre.com&gt;
Cc: Patrick Titiano &lt;ptitiano@baylibre.com&gt;
Cc: Sergei Shtylyov &lt;sergei.shtylyov@cogentembedded.com&gt;
Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Tested-by: Bin Liu &lt;b-liu@ti.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>Diffstat</a> (limited to 'drivers/usb/usbip/Kconfig')</div><table summary='diffstat' class='diffstat'>