/*
 *	X.25 Packet Layer release 002
 *
 *	This is ALPHA test software. This code may break your machine,
 *	randomly fail to work with new releases, misbehave and/or generally
 *	screw up. It might even work.
 *
 *	This code REQUIRES 2.1.15 or higher
 *
 *	This module:
 *		This module is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 *	History
 *	X.25 001	Jonathan Naylor	Started coding.
 *	X.25 002	Jonathan Naylor	New timer architecture.
 *					Centralised disconnection processing.
 */

#include <linux/errno.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>

static void x25_heartbeat_expiry(unsigned long);
static void x25_timer_expiry(unsigned long);

void x25_init_timers(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	setup_timer(&x25->timer, x25_timer_expiry, (unsigned long)sk);

	/* initialized by sock_init_data */
	sk->sk_timer.data     = (unsigned long)sk;
	sk->sk_timer.function = &x25_heartbeat_expiry;
}

void x25_start_heartbeat(struct sock *sk)
{
	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
}

void x25_stop_heartbeat(struct sock *sk)
{
	del_timer(&sk->sk_timer);
}

void x25_start_t2timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t2);
}

void x25_start_t21timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t21);
}

void x25_start_t22timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t22);
}

void x25_start_t23timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t23);
}

void x25_stop_timer(struct sock *sk)
{
	del_timer(&x25_sk(sk)->timer);
}

unsigned long x25_display_timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	if (!timer_pending(&x25->timer))
		return 0;

	return x25->timer.expires - jiffies;
}

static void x25_heartbeat_expiry(unsigned long param)
{
	struct sock *sk = (struct sock *)param;

	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
		goto restart_heartbeat;

	switch (x25_sk(sk)->state) {

		case X25_STATE_0:
			/*
			 * Magic here: If we listen() and a new link dies
			 * before it is accepted() it isn't 'dead' so doesn't
			 * get removed.
			 */
			if (sock_flag(sk, SOCK_DESTROY) ||
			    (sk->sk_state == TCP_LISTEN &&
			     sock_flag(sk, SOCK_DEAD))) {
				bh_unlock_sock(sk);
				x25_destroy_socket_from_timer(sk);
				return;
			}
			break;

		case X25_STATE_3:
			/*
			 * Check for the state of the receive buffer.
			 */
			x25_check_rbuf(sk);
			break;
	}
restart_heartbeat:
	x25_start_heartbeat(sk);
	bh_unlock_sock(sk);
}

/*
 *	Timer has expired, it may have been T2, T21, T22, or T23. We can tell
 *	by the state machine state.
 */
static inline void x25_do_timer_expiry(struct sock * sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	switch (x25->state) {

		case X25_STATE_3:	/* T2 */
			if (x25->condition & X25_COND_ACK_PENDING) {
				x25->condition &= ~X25_COND_ACK_PENDING;
				x25_enquiry_response(sk);
			}
			break;

		case X25_STATE_1:	/* T21 */
		case X25_STATE_4:	/* T22 */
			x25_write_internal(sk, X25_CLEAR_REQUEST);
			x25->state = X25_STATE_2;
			x25_start_t23timer(sk);
			break;

		case X25_STATE_2:	/* T23 */
			x25_disconnect(sk, ETIMEDOUT, 0, 0);
			break;
	}
}

static void x25_timer_expiry(unsigned long param)
{
	struct sock *sk = (struct sock *)param;

	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
		if (x25_sk(sk)->state == X25_STATE_3)
			x25_start_t2timer(sk);
	} else
		x25_do_timer_expiry(sk);
	bh_unlock_sock(sk);
}
s='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>Iago Abal &lt;mail@iagoabal.eu&gt;</td><td class='right'>2017-01-11 14:00:21 +0100</td></tr>
<tr><th>committer</th><td>Vinod Koul &lt;vinod.koul@intel.com&gt;</td><td class='right'>2017-01-25 15:35:11 +0530</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth/cmtp/cmtp.h?h=nds-private-remove&amp;id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>91539eb1fda2d530d3b268eef542c5414e54bf1a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/bluetooth/cmtp/cmtp.h?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>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=91539eb1fda2d530d3b268eef542c5414e54bf1a'>960f5ca6342ad20837aff18aad6e8ecd7da32fd6</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/bluetooth/cmtp/cmtp.h?h=nds-private-remove&amp;id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>net/bluetooth/cmtp/cmtp.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth/cmtp/cmtp.h?h=nds-private-remove&amp;id=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>6610d0edf6dc7ee97e46ab3a538a565c79d26199</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/bluetooth/cmtp/cmtp.h?h=nds-private-remove&amp;id=91539eb1fda2d530d3b268eef542c5414e54bf1a&amp;id2=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>diff</a>)</td></tr></table>
<div class='commit-subject'>dmaengine: pl330: fix double lock</div><div class='commit-msg'>The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the
following double-lock bug:

    Double lock:
    1. spin_lock_irqsave(pch-&gt;lock, flags) at pl330_free_chan_resources:2236;
    2. call to function `pl330_release_channel' immediately after;
    3. call to function `dma_pl330_rqcb' in line 1753;
    4. spin_lock_irqsave(pch-&gt;lock, flags) at dma_pl330_rqcb:1505.

I have fixed it as suggested by Marek Szyprowski.

First, I have replaced `pch-&gt;lock' with `pl330-&gt;lock' in functions
`pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids
the double-lock by acquiring a different lock than `dma_pl330_rqcb'.

NOTE that, as a result, `pl330_free_chan_resources' executes
`list_splice_tail_init' on `pch-&gt;work_list' under lock `pl330-&gt;lock',
whereas in the rest of the code `pch-&gt;work_list' is protected by
`pch-&gt;lock'. I don't know if this may cause race conditions. Similarly
`pch-&gt;cyclic' is written by `pl330_alloc_chan_resources' under
`pl330-&gt;lock' but read by `pl330_tx_submit' under `pch-&gt;lock'.

Second, I have removed locking from `pl330_request_channel' and
`pl330_release_channel' functions. Function `pl330_request_channel' is
only called from `pl330_alloc_chan_resources', so the lock is already
held. Function `pl330_release_channel' is called from
`pl330_free_chan_resources', which already holds the lock, and from
`pl330_del'. Function `pl330_del' is called in an error path of
`pl330_probe' and at the end of `pl330_remove', but I assume that there
cannot be concurrent accesses to the protected data at those points.

Signed-off-by: Iago Abal &lt;mail@iagoabal.eu&gt;
Reviewed-by: Marek Szyprowski &lt;m.szyprowski@samsung.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/?h=nds-private-remove&amp;id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>Diffstat</a> (limited to 'net/bluetooth/cmtp/cmtp.h')</div><table summary='diffstat' class='diffstat'>