#
# Asynchronous Transfer Mode (ATM)
#

config ATM
	tristate "Asynchronous Transfer Mode (ATM)"
	---help---
	  ATM is a high-speed networking technology for Local Area Networks
	  and Wide Area Networks.  It uses a fixed packet size and is
	  connection oriented, allowing for the negotiation of minimum
	  bandwidth requirements.

	  In order to participate in an ATM network, your Linux box needs an
	  ATM networking card. If you have that, say Y here and to the driver
	  of your ATM card below.

	  Note that you need a set of user-space programs to actually make use
	  of ATM.  See the file <file:Documentation/networking/atm.txt> for
	  further details.

config ATM_CLIP
	tristate "Classical IP over ATM"
	depends on ATM && INET
	help
	  Classical IP over ATM for PVCs and SVCs, supporting InARP and
	  ATMARP. If you want to communication with other IP hosts on your ATM
	  network, you will typically either say Y here or to "LAN Emulation
	  (LANE)" below.

config ATM_CLIP_NO_ICMP
	bool "Do NOT send ICMP if no neighbour"
	depends on ATM_CLIP
	help
	  Normally, an "ICMP host unreachable" message is sent if a neighbour
	  cannot be reached because there is no VC to it in the kernel's
	  ATMARP table. This may cause problems when ATMARP table entries are
	  briefly removed during revalidation. If you say Y here, packets to
	  such neighbours are silently discarded instead.

config ATM_LANE
	tristate "LAN Emulation (LANE) support"
	depends on ATM
	help
	  LAN Emulation emulates services of existing LANs across an ATM
	  network. Besides operating as a normal ATM end station client, Linux
	  LANE client can also act as an proxy client bridging packets between
	  ELAN and Ethernet segments. You need LANE if you want to try MPOA.

config ATM_MPOA
	tristate "Multi-Protocol Over ATM (MPOA) support"
	depends on ATM && INET && ATM_LANE!=n
	help
	  Multi-Protocol Over ATM allows ATM edge devices such as routers,
	  bridges and ATM attached hosts establish direct ATM VCs across
	  subnetwork boundaries. These shortcut connections bypass routers
	  enhancing overall network performance.

config ATM_BR2684
	tristate "RFC1483/2684 Bridged protocols"
	depends on ATM && INET
	help
	  ATM PVCs can carry ethernet PDUs according to RFC2684 (formerly 1483)
	  This device will act like an ethernet from the kernels point of view,
	  with the traffic being carried by ATM PVCs (currently 1 PVC/device).
	  This is sometimes used over DSL lines.  If in doubt, say N.

config ATM_BR2684_IPFILTER
	bool "Per-VC IP filter kludge"
	depends on ATM_BR2684
	help
	  This is an experimental mechanism for users who need to terminate a
	  large number of IP-only vcc's.  Do not enable this unless you are sure
	  you know what you are doing.
<a href='/cgit.cgi/linux/net-next.git/commit/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?id=966d2b04e070bc040319aaebfec09e0144dc3341'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/ieee802154?id=966d2b04e070bc040319aaebfec09e0144dc3341'>ieee802154</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/ieee802154/ieee802154.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>ieee802154.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='966d2b04e070bc040319aaebfec09e0144dc3341'/><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>Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;</td><td class='right'>2017-01-28 06:42:20 -0600</td></tr>
<tr><th>committer</th><td>Tejun Heo &lt;tj@kernel.org&gt;</td><td class='right'>2017-01-28 07:49:42 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ieee802154/ieee802154.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/ieee802154/ieee802154.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>4b96156e3d1dd4dfd6039b7c219c9dc4616da52d</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/ieee802154/ieee802154.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>net/ieee802154/ieee802154.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ieee802154/ieee802154.h?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ieee802154/ieee802154.h?id=966d2b04e070bc040319aaebfec09e0144dc3341&amp;id2=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>diff</a>)</td></tr></table>
<div class='commit-subject'>percpu-refcount: fix reference leak during percpu-atomic transition</div><div class='commit-msg'>percpu_ref_tryget() and percpu_ref_tryget_live() should return
"true" IFF they acquire a reference. But the return value from
atomic_long_inc_not_zero() is a long and may have high bits set,
e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
is bool so the reference may actually be acquired but the routines
return "false" which results in a reference leak since the caller
assumes it does not need to do a corresponding percpu_ref_put().

This was seen when performing CPU hotplug during I/O, as hangs in
blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start)
raced with percpu_ref_tryget (blk_mq_timeout_work).
Sample stack trace:

__switch_to+0x2c0/0x450
__schedule+0x2f8/0x970
schedule+0x48/0xc0
blk_mq_freeze_queue_wait+0x94/0x120
blk_mq_queue_reinit_work+0xb8/0x180
blk_mq_queue_reinit_prepare+0x84/0xa0
cpuhp_invoke_callback+0x17c/0x600
cpuhp_up_callbacks+0x58/0x150
_cpu_up+0xf0/0x1c0
do_cpu_up+0x120/0x150
cpu_subsys_online+0x64/0xe0
device_online+0xb4/0x120
online_store+0xb4/0xc0
dev_attr_store+0x68/0xa0
sysfs_kf_write+0x80/0xb0
kernfs_fop_write+0x17c/0x250
__vfs_write+0x6c/0x1e0
vfs_write+0xd0/0x270
SyS_write+0x6c/0x110
system_call+0x38/0xe0

Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS,
and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests.
However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0
and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set.

The fix is to make the tryget routines use an actual boolean internally instead
of the atomic long result truncated to a int.

Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints
Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751
Signed-off-by: Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;
Reviewed-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>Diffstat</a> (limited to 'net/ieee802154/ieee802154.h')</div><table summary='diffstat' class='diffstat'>