The link change is detected via the interrupt pipe, and bulk
pipes are responsible for transfering packets, so it is reasonable
to stop bulk transfer after link is reported as off.

Two adavantages may be obtained with stopping bulk transfer
after link becomes off:

- USB bus bandwidth is saved(USB bus is shared bus except for
USB3.0), for example, lots of 'IN' token packets and 'NYET'
handshake packets is transfered on 2.0 bus.

- probabaly power might be saved for usb host controller since
cancelling bulk transfer may disable the asynchronous schedule of
host controller.

With this patch, when link becomes off, about ~10% performance
boost can be found on bulk transfer of anther usb device which
is attached to same bus with the usbnet device, see below
test on next-20130410:

- read from usb mass storage(Sandisk Extreme USB 3.0) on pandaboard
with below command after unplugging ethernet cable:

	dd if=/dev/sda iflag=direct of=/dev/null bs=1M count=800

- without the patch
1, 838860800 bytes (839 MB) copied, 36.2216 s, 23.2 MB/s
2, 838860800 bytes (839 MB) copied, 35.8368 s, 23.4 MB/s
3, 838860800 bytes (839 MB) copied, 35.823 s, 23.4 MB/s
4, 838860800 bytes (839 MB) copied, 35.937 s, 23.3 MB/s
5, 838860800 bytes (839 MB) copied, 35.7365 s, 23.5 MB/s
average: 23.6MB/s

- with the patch
1, 838860800 bytes (839 MB) copied, 32.3817 s, 25.9 MB/s
2, 838860800 bytes (839 MB) copied, 31.7389 s, 26.4 MB/s
3, 838860800 bytes (839 MB) copied, 32.438 s, 25.9 MB/s
4, 838860800 bytes (839 MB) copied, 32.5492 s, 25.8 MB/s
5, 838860800 bytes (839 MB) copied, 31.6178 s, 26.5 MB/s
average: 26.1MB/s
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use usbnet_link_change to handle link change centrally.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces the API of usbnet_link_change, so that
usbnet can handle link change centrally, which may help to
implement killing traffic URBs for saving USB bus bandwidth
and host controller power.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

alloc failures already get standardized OOM
messages and a dump_stack.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is normal for minidrivers accumulating frames to return NULL
from their tx_fixup function. We do not want to count this as a
drop, or log any debug messages.  A different exit path is
therefore chosen for such drivers, skipping the debug message
and the tx_dropped increment.

The test for accumulating drivers was however completely bogus,
making the exit path selection depend on whether the user had
enabled tx_err logging or not. This would arbitrarily mess up
accounting for both accumulating and non-accumulating minidrivers,
and would result in unwanted debug messages for the accumulating
drivers.

Fix by testing for FLAG_MULTI_PACKET instead, which probably was
the intention from the beginning.  This usage match the documented
behaviour of this flag:

 Indicates to usbnet, that USB driver accumulates multiple IP packets.
 Affects statistic (counters) and short packet handling.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A device sending 0 length frames as fast as it can has been
observed killing the host system due to the resulting memory
pressure.

Temporarily disable RX skb allocation and URB submission when
the current error ratio is high, preventing us from trying to
allocate an infinite number of skbs.  Reenable as soon as we
are finished processing the done queue, allowing the device
to continue working after short error bursts.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We do have some USB net devices, which cannot do ARP.
so we can introduce a new flag FLAG_NOARP, then client drivers
can easily handle this kind of devices
Signed-off-by: NWei Shuai <cpuwolf@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Centralise common code for manage_power() in usbnet
by making a generic simple implementation
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If a device fails to do remote wakeup, this is no reason
to abort an open totally. This patch just continues without
runtime PM.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

when something goes wrong, a flood of these messages can be
generated by usbnet (thousands per second).  This doesn't
generally *help* the condition so this patch ratelimits the
rate of their generation.

There's an underlying problem in usbnet's kevent deferral
mechanism which needs fixing, specifically that events *can*
get dropped and not handled.  This patch doesn't address this,
but just mitigates fallout caused by the current implemention.
Signed-off-by: NSteve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch gets the runtime PM reference count before calling
usbnet_{read|write}_cmd, and puts it after completion of the
usbnet_{read|write}_cmd, so that the usb control message can always
be sent to one active device in the non-PM context.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces the below two helpers to prepare for solving
the usbnet runtime PM problem, which may cause some network utilities
(ifconfig, ethtool,...) touch a suspended device.

	usbnet_read_cmd_nopm()
	usbnet_write_cmd_nopm()

The above two helpers should be called by usbnet resume/suspend
callback to avoid deadlock.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Driver anchors the tx urbs and defers the urb submission if
a transmit request comes when the interface is suspended.
Anchoring urb increments the urb reference count. These
deferred urbs are later accessed by calling usb_get_from_anchor()
for submission during interface resume. usb_get_from_anchor()
unanchors the urb but urb reference count remains same.
This causes the urb reference count to remain non-zero
after usb_free_urb() gets called and urb never gets freed.
Hence call usb_put_urb() after anchoring the urb to properly
balance the reference count for these deferred urbs. Also,
unanchor these deferred urbs during disconnect, to free them
up.
Signed-off-by: NHemant Kumar <hemantk@codeaurora.org>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces the below 3 usb command helpers:

	usbnet_read_cmd / usbnet_write_cmd / usbnet_write_cmd_async

so that each low level driver doesn't need to implement them
by itself, and the dma buffer allocation for usb transfer and
runtime PM things can be handled just in one place.
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some device types support a form of power management in which
the device suggests to the host that the device may be suspended
now. Support for that is best located in usbnet.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 5d65878d7031b6c39054b282faceff406bb2fda9.
The upper layers call usbnet_start_xmit() with a valid skb.
However cdc_ncm abuses this method by calling it with NULL
to trigger IO for the aggregated private skb holding erlier
packets. Until cdc_ncm is fixed, the check for NULL must
be reintroduced.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

usbnet_start_xmit() is always called with a valid skb
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Suspending an open usbnet device results in constant
rescheduling of usbnet_bh.

commit 65841fd5 "usbnet: handle remote wakeup asap"
refactored the usbnet_bh code to allow sharing the
urb allocate and submit code with usbnet_resume. In
this process, a test for, and immediate return on,
ENOLINK from rx_submit was unintentionally dropped.

The rx queue will not grow if rx_submit fails,
making usbnet_bh reschedule itself.  This results
in a softirq storm if the error is persistent.
rx_submit translates the usb_submit_urb error
EHOSTUNREACH into ENOLINK, so this is an expected
and persistent error for a suspended device. The
old code tested for this condition and avoided
rescheduling.  Putting this test back.

Cc: <stable@vger.kernel.org> # v3.5
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Oliver Neukum <oneukum@suse.de>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A usbnet device can share a multifunction device
with a storage device. If the storage device is autoresumed
the usbnet devices also needs to be autoresumed. Allocating
memory with GFP_KERNEL can deadlock in this case.

This should go back into all kernels that have
commit 65841fd5
That is 3.5
Signed-off-by: NOliver Neukum <oneukum@suse.de>
CC: stable@kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Convert the existing uses of random_ether_addr to
the new eth_random_addr.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If usbnet is resumed by remote wakeup, generally there are
some packets comming to be handled, so allocate and submit
rx URBs in usbnet_resume to avoid delays introduced by tasklet.
Otherwise, usbnet may have been runtime suspended before the
usbnet_bh is executed to schedule Rx URBs.

Without the patch, usbnet can't recieve any packets from peer
in runtime suspend state if runtime PM is enabled and
autosuspend_delay is set as zero.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch decreases dev->suspend_count in the -EBUSY failure path
of usbnet_suspend. Without the change, the later runtime suspend
will do nothing except for increasing dev->suspend_count.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Without clearing OPEN flag in failure path, runtime or system resume
may submit interrupt/rx URB and start tx queue mistakenly on a
interface in DOWN state.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As seen on smsc75xx, driver_info->description being longer than 32
characters messes up 'ethtool -i' output.
Signed-off-by: NPhil Sutter <phil.sutter@viprinet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The line below in intr_complete isn't needed,

	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);

so just remove it.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove declaration for intr_complete so that ctags may be happy to
decrease duplicated symbols, also decrease one line code.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

usb_device is parent device of usb_interface in the view of driver
model, so its reference count is always held during .probe/.disconnect
of usb_interface instance.

This patch just removes the unnecessay usb_get/put_dev.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 4231d47e(net/usbnet: avoid
recursive locking in usbnet_stop()) fixes the recursive locking
problem by releasing the skb queue lock before unlink, but may
cause skb traversing races:
	- after URB is unlinked and the queue lock is released,
	the refered skb and skb->next may be moved to done queue,
	even be released
	- in skb_queue_walk_safe, the next skb is still obtained
	by next pointer of the last skb
	- so maybe trigger oops or other problems

This patch extends the usage of entry->state to describe 'start_unlink'
state, so always holding the queue(rx/tx) lock to change the state if
the referd skb is in rx or tx queue because we need to know if the
refered urb has been started unlinking in unlink_urbs.

The other part of this patch is based on Huajun's patch:
always traverse from head of the tx/rx queue to get skb which is
to be unlinked but not been started unlinking.
Signed-off-by: NHuajun Li <huajun.li.lee@gmail.com>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: stable@kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If register_netdev returns failure, the dev->interrupt and
its transfer buffer should be released, so just fix it.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The transfer buffer of dev->interrupt is allocated in .probe path,
but not freed in .disconnet path, so mark the interrupt URB as
URB_FREE_BUFFER to free the buffer when the URB is destroyed.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

usbnet should centrally handle busy reporting in the rx path
so subdrivers need not worry. This hurts use cases which do
rx only or predominantly.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

URB unlinking is always racing with its completion and tx_complete
may be called before or during running usb_unlink_urb, so tx_complete
must not clear urb->dev since it will be used in unlink path,
otherwise invalid memory accesses or usb device leak may be caused
inside usb_unlink_urb.

Cc: stable@kernel.org
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 4231d47e(net/usbnet: avoid
recursive locking in usbnet_stop()) fixes the recursive locking
problem by releasing the skb queue lock, but it makes usb_unlink_urb
racing with defer_bh, and the URB to being unlinked may be freed before
or during calling usb_unlink_urb, so use-after-free problem may be
triggerd inside usb_unlink_urb.

The patch fixes the use-after-free problem by increasing URB
reference count with skb queue lock held before calling
usb_unlink_urb, so the URB won't be freed until return from
usb_unlink_urb.

Cc: stable@kernel.org
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oliver@neukum.org>
Reported-by: NDave Jones <davej@redhat.com>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If host is going to autosuspend function with two interfaces and
if IP packet has arrived in-between of two usbnet_suspend() callbacks,
i.e usbnet_resume() is called in-between, tx data flow is stopped.
When autosuspend timer expires and device is put to autosuspend
again, tx queue is waked up and data can be sent again.
This behavior might be repeated several times in a row.

Tested on Intel/ARM.
Reviewed-by: NSjur Brændeland <sjur.brandeland@stericsson.com>
Tested-by: NDmitry Tarnyagin <dmitry.tarnyagin@stericsson.com>
Signed-off-by: NAlexey Orishko <alexey.orishko@stericsson.com>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

network drivers should reserve some headroom on incoming skbs so that we
dont need expensive reallocations, eg forwarding packets in tunnels.

This NET_SKB_PAD padding is done in various helpers, like
__netdev_alloc_skb_ip_align() in this patch, combining NET_SKB_PAD and
NET_IP_ALIGN magic.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

|kernel BUG at kernel/rtmutex.c:724!
|[<c029599c>] (rt_spin_lock_slowlock+0x108/0x2bc) from [<c01c2330>] (defer_bh+0x1c/0xb4)
|[<c01c2330>] (defer_bh+0x1c/0xb4) from [<c01c3afc>] (rx_complete+0x14c/0x194)
|[<c01c3afc>] (rx_complete+0x14c/0x194) from [<c01cac88>] (usb_hcd_giveback_urb+0xa0/0xf0)
|[<c01cac88>] (usb_hcd_giveback_urb+0xa0/0xf0) from [<c01e1ff4>] (musb_giveback+0x34/0x40)
|[<c01e1ff4>] (musb_giveback+0x34/0x40) from [<c01e2b1c>] (musb_advance_schedule+0xb4/0x1c0)
|[<c01e2b1c>] (musb_advance_schedule+0xb4/0x1c0) from [<c01e2ca8>] (musb_cleanup_urb.isra.9+0x80/0x8c)
|[<c01e2ca8>] (musb_cleanup_urb.isra.9+0x80/0x8c) from [<c01e2ed0>] (musb_urb_dequeue+0xec/0x108)
|[<c01e2ed0>] (musb_urb_dequeue+0xec/0x108) from [<c01cbb90>] (unlink1+0xbc/0xcc)
|[<c01cbb90>] (unlink1+0xbc/0xcc) from [<c01cc2ec>] (usb_hcd_unlink_urb+0x54/0xa8)
|[<c01cc2ec>] (usb_hcd_unlink_urb+0x54/0xa8) from [<c01c2a84>] (unlink_urbs.isra.17+0x2c/0x58)
|[<c01c2a84>] (unlink_urbs.isra.17+0x2c/0x58) from [<c01c2b44>] (usbnet_terminate_urbs+0x94/0x10c)
|[<c01c2b44>] (usbnet_terminate_urbs+0x94/0x10c) from [<c01c2d68>] (usbnet_stop+0x100/0x15c)
|[<c01c2d68>] (usbnet_stop+0x100/0x15c) from [<c020f718>] (__dev_close_many+0x94/0xc8)

defer_bh() takes the lock which is hold during unlink_urbs(). The safe
walk suggest that the skb will be removed from the list and this is done
by defer_bh() so it seems to be okay to drop the lock here.

Cc: stable@kernel.org
Reported-by: NAníbal Almeida Pinto <anibal.pinto@efacec.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NOliver Neukum <oliver@neukum.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

alloc_etherdev has a generic OOM/unable to alloc message.
Remove the duplicative messages after alloc_etherdev calls.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes the bug added in commit v3.1-rc7-1055-gf9b491ec
SKB can be NULL at this point, at least for cdc-ncm.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to make USB-to-Ethernet-adapters (depending on usbnet) support
timestamping, the "skb_defer_rx_timestamp" and "skb_tx_timestamp" function
calls are added.
Signed-off-by: NMichael Riesch <michael@riesch.at>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>