#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/export.h>
#include <asm/syscall.h>

static int collect_syscall(struct task_struct *target, long *callno,
			   unsigned long args[6], unsigned int maxargs,
			   unsigned long *sp, unsigned long *pc)
{
	struct pt_regs *regs;

	if (!try_get_task_stack(target)) {
		/* Task has no stack, so the task isn't in a syscall. */
		*callno = -1;
		return 0;
	}

	regs = task_pt_regs(target);
	if (unlikely(!regs)) {
		put_task_stack(target);
		return -EAGAIN;
	}

	*sp = user_stack_pointer(regs);
	*pc = instruction_pointer(regs);

	*callno = syscall_get_nr(target, regs);
	if (*callno != -1L && maxargs > 0)
		syscall_get_arguments(target, regs, 0, maxargs, args);

	put_task_stack(target);
	return 0;
}

/**
 * task_current_syscall - Discover what a blocked task is doing.
 * @target:		thread to examine
 * @callno:		filled with system call number or -1
 * @args:		filled with @maxargs system call arguments
 * @maxargs:		number of elements in @args to fill
 * @sp:			filled with user stack pointer
 * @pc:			filled with user PC
 *
 * If @target is blocked in a system call, returns zero with *@callno
 * set to the the call's number and @args filled in with its arguments.
 * Registers not used for system call arguments may not be available and
 * it is not kosher to use &struct user_regset calls while the system
 * call is still in progress.  Note we may get this result if @target
 * has finished its system call but not yet returned to user mode, such
 * as when it's stopped for signal handling or syscall exit tracing.
 *
 * If @target is blocked in the kernel during a fault or exception,
 * returns zero with *@callno set to -1 and does not fill in @args.
 * If so, it's now safe to examine @target using &struct user_regset
 * get() calls as long as we're sure @target won't return to user mode.
 *
 * Returns -%EAGAIN if @target does not remain blocked.
 *
 * Returns -%EINVAL if @maxargs is too large (maximum is six).
 */
int task_current_syscall(struct task_struct *target, long *callno,
			 unsigned long args[6], unsigned int maxargs,
			 unsigned long *sp, unsigned long *pc)
{
	long state;
	unsigned long ncsw;

	if (unlikely(maxargs > 6))
		return -EINVAL;

	if (target == current)
		return collect_syscall(target, callno, args, maxargs, sp, pc);

	state = target->state;
	if (unlikely(!state))
		return -EAGAIN;

	ncsw = wait_task_inactive(target, state);
	if (unlikely(!ncsw) ||
	    unlikely(collect_syscall(target, callno, args, maxargs, sp, pc)) ||
	    unlikely(wait_task_inactive(target, state) != ncsw))
		return -EAGAIN;

	return 0;
}
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/bridge?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>bridge</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/bridge/br.c?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>br.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='407788b51db6f6aab499d02420082f436abf3238'/><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'>2017-01-24 09:18:57 -0600</td></tr>
<tr><th>committer</th><td>Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;</td><td class='right'>2017-01-25 11:02:29 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bridge/br.c?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>407788b51db6f6aab499d02420082f436abf3238</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/bridge/br.c?id=407788b51db6f6aab499d02420082f436abf3238'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>b2fb3c885baf47cd2bd8ee0429f423b352e11905</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/bridge/br.c?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>net/bridge/br.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bridge/br.c?h=nds-private-remove&amp;id=7a308bb3016f57e5be11a677d15b821536419d36'>7a308bb3016f57e5be11a677d15b821536419d36</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/bridge/br.c?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238&amp;id2=7a308bb3016f57e5be11a677d15b821536419d36'>diff</a>)</td></tr></table>
<div class='commit-subject'>usb: musb: Fix host mode error -71 regression</div><div class='commit-msg'>Commit 467d5c980709 ("usb: musb: Implement session bit based runtime PM for
musb-core") started implementing musb generic runtime PM support by
introducing devctl register session bit based state control.

This caused a regression where if a USB mass storage device is connected
to a USB hub, we can get:

usb 1-1: reset high-speed USB device number 2 using musb-hdrc
usb 1-1: device descriptor read/64, error -71
usb 1-1.1: new high-speed USB device number 4 using musb-hdrc

This is because before the USB storage device is connected, musb is
in OTG_STATE_A_SUSPEND. And we currently only set need_finish_resume
in musb_stage0_irq() and the related code calling finish_resume_work
in musb_resume() and musb_runtime_resume() never gets called.

To fix the issue, we can call schedule_delayed_work() directly in
musb_stage0_irq() to have finish_resume_work run.

And we should no longer never get interrupts when when suspended.
We have changed musb to no longer need pm_runtime_irqsafe().
The need_finish_resume flag was added in commit 9298b4aad37e ("usb:
musb: fix device hotplug behind hub") and no longer applies as far
as I can tell. So let's just remove the earlier code that no longer
is needed.

Fixes: 467d5c980709 ("usb: musb: Implement session bit based runtime PM for musb-core")
Reported-by: Bin Liu &lt;b-liu@ti.com&gt;
Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Signed-off-by: Bin Liu &lt;b-liu@ti.com&gt;
Cc: stable &lt;stable@vger.kernel.org&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/?h=nds-private-remove&amp;id=407788b51db6f6aab499d02420082f436abf3238'>Diffstat</a> (limited to 'net/bridge/br.c')</div><table summary='diffstat' class='diffstat'>