Under harsh testing conditions, including low memory, the guest would
stop receiving packets. With this patch applied we no longer see any
problems in the driver while performing these tests for extended periods
of time.

Make sure napi is scheduled subsequent to each napi_enable.
Signed-off-by: NBruce Rogers <brogers@novell.com>
Signed-off-by: NOlaf Kirch <okir@suse.de>
Cc: stable@kernel.org
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace skb->csum_start - skb_headroom(skb) with skb_checksum_start_offset().

Note for usb/smsc95xx: skb->data - skb->head == skb_headroom(skb).
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For device that supports VIRTIO_NET_F_STATUS, there's no need to
assume the link is up and we need to call nerif_carrier_off() before
querying device status, otherwise we may get wrong operstate after
diver was loaded because the link watch event was not fired as
expected.

For device that does not support VIRITO_NET_F_STATUS, we could not get
its status through virtnet_update_status() and what we can only do is
always assuming the link is up.
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The driver name and bus address for a net_device can normally be found
through the driver model now.  Instead of requiring drivers to provide
this information redundantly through the ethtool_ops::get_drvinfo
operation, use the driver model to do so if the driver does not define
the operation.  Since ETHTOOL_GDRVINFO no longer requires the driver
to implement any operations, do not require net_device::ethtool_ops to
be set either.

Remove implementations of get_drvinfo and ethtool_ops that provide
only this information.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I often use "ethtool -i" command to check what driver controls the
ehternet device.  But because current virtio_net driver doesn't
support "ethtool -i", it becomes the following:

        # ethtool -i eth3
        Cannot get driver information: Operation not supported

This patch simply adds the "ethtool -i" support. The following is the
result when using the virtio_net driver with my patch applied to.

        # ethtool -i eth3
        driver: virtio_net
        version: N/A
        firmware-version: N/A
        bus-info: virtio0

Personally, "-i" is one of the most frequently-used option, and most
network drivers support "ethtool -i", so I think virtio_net also
should do.
Signed-off-by: NTaku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (use ARRAY_SIZE)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

virtio net will never try to overflow the TX ring, so the only reason
add_buf may fail is out of memory. Thus, we can not stop the
device until some request completes - there's no guarantee anything
at all is outstanding.

Make the error message clearer as well: error here does not
indicate queue full.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (...and avoid TX_BUSY)
Cc: stable@kernel.org  # .34.x (s/virtqueue_/vi->svq->vq_ops->/)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently fill all of RX ring, then add_buf
returns ENOSPC, which gets mis-detected as an out of
memory condition and causes us to reschedule the work,
and so on forever. Fix this by oom = err == -ENOMEM;
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # .34.x
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

virtio-net bounces buffer allocations off to
a thread if it can't allocate buffers from the atomic
pool. However, if posting buffers still requires atomic
buffers, this is unlikely to succeed.
Fix by passing in the proper gfp_t parameter.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Switch virtio_net to new virtqueue_xxx wrappers.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Pointed out by Stephen Rothwell.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add missing sg_init_table for sg_set_buf in virtio_net which
induced in defer skb patch.
Reported-by: NThomas Müller <thomas@mathtm.de>
Tested-by: NThomas Müller <thomas@mathtm.de>
Signed-off-by: NShirley Ma <xma@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move sg structure off stack and into virtnet_info structure.
This helps remove extra sg_init_table calls as well as reduce
stack usage.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Converts the list and the core manipulating with it to be the same as uc_list.

+uses two functions for adding/removing mc address (normal and "global"
 variant) instead of a function parameter.
+removes dev_mcast.c completely.
+exposes netdev_hw_addr_list_* macros along with __hw_addr_* functions for
 manipulation with lists on a sandbox (used in bonding and 80211 drivers)
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add missing sg_init_table for sg_set_buf in virtio_net which
induced in defer skb patch.
Reported-by: NThomas Müller <thomas@mathtm.de>
Tested-by: NThomas Müller <thomas@mathtm.de>
Signed-off-by: NShirley Ma <xma@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

This is no longer needed. I missed to remove this in
567ec874 ("net: convert multiple
drivers to use netdev_for_each_mc_addr, part6")
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now we have a virtio detach API (in commit
f9bfbebf), we don't need to track xmit
skbs in the virio_net driver, which improves transmission performance.
Signed-off-by: NShirley Ma <xma@us.ibm.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch replaces dev->mc_count in all drivers (hopefully I didn't miss
anything). Used spatch and did small tweaks and conding style changes when
it was suitable.

Jirka
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

virtio_net receives packets from its pre-allocated vring buffers, then it
delivers these packets to upper layer protocols as skb buffs. So it's not
necessary to pre-allocate skb for each mergable buffer, then frees extra
skbs when buffers are merged into a large packet. This patch has deferred
skb allocation in receiving packets for both big packets and mergeable buffers
to reduce skb pre-allocations and skb frees. It frees unused buffers by calling
detach_unused_buf in vring, so recv skb queue is not needed.
Signed-off-by: NShirley Ma <xma@us.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I have seen RX stalls on a machine that experienced a suspected
OOM.  After the stall, the RX buffer is empty on the guest side
and there are exactly 16 entries available on the host side.  As
the number of entries is less than that required by a maximal
skb, the host cannot proceed.

The guest did not have a refill job scheduled.

My diagnosis is that an OOM had occured, with the delayed refill
job scheduled.  The job was able to allocate at least one skb, but
not enough to overcome the minimum required by the host to proceed.

As the refill job would only reschedule itself if it failed completely
to allocate any skbs, this would lead to an RX stall.

The following patch removes this stall possibility by always
rescheduling the refill job until the ring is totally refilled.

Testing has shown that the RX stall no longer occurs whereas
previously it would occur within a day.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces three macros to work with uc list from net drivers.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Only files where David Miller is the primary git-signer.
wireless, wimax, ixgbe, etc are not modified.

Compile tested x86 allyesconfig only
Not all files compiled (not x86 compatible)

Added a few > 80 column lines, which I ignored.
Existing checkpatch complaints ignored.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit

	3d1285be (move virtnet_remove to .devexit.text)

introduced the first reference to __devexit in struct virtio_driver
virtio_net which upset modpost ("Section mismatch in reference from the
variable virtio_net to the function .devexit.text:virtnet_remove()").

Fix this by renaming virtio_net to virtio_net_driver.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reported-by: NMichael S. Tsirkin <mst@redhat.com>
Blame-taken-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

virtio net used to unlink skbs from send queues on error,
but ever since 48925e37
we do not do this. This causes guest data corruption and crashes
with vhost since net core can requeue the skb or free it without
it being taken off the list.

This patch fixes this by queueing the skb after successful
transmit.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rusty,

commit 3ca4f5ca
    virtio: add virtio IDs file
moved all device IDs into a single file. While the change itself is
a very good one, it can break userspace applications. For example
if a userspace tool wanted to get the ID of virtio_net it used to
include virtio_net.h. This does no longer work, since virtio_net.h
does not include virtio_ids.h.
This patch moves all "#include <linux/virtio_ids.h>" from the C
files into the header files, making the header files compatible with
the old ones.

In addition, this patch exports virtio_ids.h to userspace.

CC: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Because netpoll can call netdevice start_xmit() method with
irqs disabled, drivers should not call kfree_skb() from
their start_xmit(), but use dev_kfree_skb_any() instead.

Oct  8 11:16:52 172.30.1.31 [113074.791813] ------------[ cut here ]------------
Oct  8 11:16:52 172.30.1.31 [113074.791813] WARNING: at net/core/skbuff.c:398 \
                skb_release_head_state+0x64/0xc8()
Oct  8 11:16:52 172.30.1.31 [113074.791813] Hardware name:
Oct  8 11:16:52 172.30.1.31 [113074.791813] Modules linked in: netconsole ocfs2 jbd2 quota_tree \
ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue configfs crc32c drbd cn loop \
serio_raw psmouse snd_pcm snd_timer snd soundcore snd_page_alloc virtio_net pcspkr parport_pc parport \
i2c_piix4 i2c_core button processor evdev ext3 jbd mbcache dm_mirror dm_region_hash dm_log dm_snapshot \
dm_mod ide_cd_mod cdrom ata_generic ata_piix virtio_blk libata scsi_mod piix ide_pci_generic ide_core \
                virtio_pci virtio_ring virtio floppy thermal fan thermal_sys [last unloaded: netconsole]
Oct  8 11:16:52 172.30.1.31 [113074.791813] Pid: 11132, comm: php5-cgi Tainted: G        W  \
                2.6.31.2-vserver #1
Oct  8 11:16:52 172.30.1.31 [113074.791813] Call Trace:
Oct  8 11:16:52 172.30.1.31 [113074.791813] <IRQ>  [<ffffffff81253cd5>] ? \
                skb_release_head_state+0x64/0xc8
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81253cd5>] ? skb_release_head_state+0x64/0xc8
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81049ae1>] ? warn_slowpath_common+0x77/0xa3
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81253cd5>] ? skb_release_head_state+0x64/0xc8
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81253a1a>] ? __kfree_skb+0x9/0x7d
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffffa01cb139>] ? free_old_xmit_skbs+0x51/0x6e \
                [virtio_net]
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffffa01cbc85>] ? start_xmit+0x26/0xf2 [virtio_net]
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff8126934f>] ? netpoll_send_skb+0xd2/0x205
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffffa0429216>] ? write_msg+0x90/0xeb [netconsole]
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81049f06>] ? __call_console_drivers+0x5e/0x6f
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff8102b49d>] ? kvm_clock_read+0x4d/0x52
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff8104a082>] ? release_console_sem+0x115/0x1ba
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff8104a632>] ? vprintk+0x2f2/0x34b
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff8106b142>] ? vx_update_load+0x18/0x13e
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81308309>] ? printk+0x4e/0x5d
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff8102b49d>] ? kvm_clock_read+0x4d/0x52
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81070b62>] ? getnstimeofday+0x55/0xaf
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81062683>] ? ktime_get_ts+0x21/0x49
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff810626b7>] ? ktime_get+0xc/0x41
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81062788>] ? hrtimer_interrupt+0x9c/0x146
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81024a4b>] ? smp_apic_timer_interrupt+0x80/0x93
Oct  8 11:16:52 172.30.1.31 [113074.791813] [<ffffffff81011663>] ? apic_timer_interrupt+0x13/0x20
Oct  8 11:16:52 172.30.1.31 [113074.791813] <EOI>  [<ffffffff8130a9eb>] ? _spin_unlock_irq+0xd/0x31
Reported-and-tested-by: NMassimo Cetra <mcetra@navynet.it>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Bug-Entry: http://bugzilla.kernel.org/show_bug.cgi?id=14378Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function virtnet_remove is used only wrapped by __devexit_p so define
it using __devexit.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alex Williamson <alex.williamson@hp.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Saves us one cycle of alloc-add-free if the queue was full.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (modified)

Now we can tell the theoretical capacity remaining in the output
queue, virtio_net can waste entries by stopping the queue early.

It doesn't work in the case of indirect buffers and kmalloc failure,
but that's rare (we could drop the packet in that case, but other
drivers return TX_BUSY for similar reasons).

For the record, I think this patch reflects poorly on the linux
network API.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>

We put the virtio_net_hdr into the skb's cb region; turn this into a
union to clean up the code slightly and allow future expansion.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>

The virtio_net driver is complicated by the two methods of freeing old
xmit buffers (in addition to freeing old ones at the start of the xmit
path).

The original code used a 1/10 second timer attached to xmit_free(),
reset on every xmit.  Before we orphaned skbs on xmit, the
transmitting userspace could block with a full socket until the timer
fired, the skb destructor was called, and they were re-woken.

So we added the VIRTIO_F_NOTIFY_ON_EMPTY feature: supporting devices
send an interrupt (even if normally suppressed) on an empty xmit ring
which makes us schedule xmit_tasklet().  This was a benchmark win.

Unfortunately, VIRTIO_F_NOTIFY_ON_EMPTY makes quite a lot of work: a
host which is faster than the guest will fire the interrupt every xmit
packet (slowing the guest down further).  Attempting mitigation in the
host adds overhead of userspace timers (possibly with the additional
pain of signals), and risks increasing latency anyway if you get it
wrong.

In practice, this effect was masked by benchmarks which take advantage
of GSO (with its inherent transmit batching), but it's still there.

Now we orphan xmitted skbs, the pressure is off: remove both paths and
no longer request VIRTIO_F_NOTIFY_ON_EMPTY.  Note that the current
QEMU will notify us even if we don't negotiate this feature (legal,
but suboptimal); a patch is outstanding to improve that.

Move the skb_orphan/nf_reset to after we've done the send and notified
the other end, for a slight optimization.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Mark McLoughlin <markmc@redhat.com>

This effectively reverts 99ffc696
"virtio: wean net driver off NETDEV_TX_BUSY".

The complexity of queuing an skb (setting a tasklet to re-xmit) is
questionable, especially once we get rid of the other reason for the
tasklet in the next patch.

If the skb won't fit in the tx queue, just return NETDEV_TX_BUSY.
This is frowned upon, so a followup patch uses a more complex solution.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Herbert Xu <herbert@gondor.apana.org.au>

The complex transmit free logic was introduced to avoid hangs on
removing the ip_conntrack module and also because drivers aren't
generally supposed to keep stale skbs for unbounded times.

After some debate, it was decided that while doing skb_orphan()
generally is a rat's nest, we can do it in this driver.  Following
patches take advantage of this.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Virtio IDs are spread all over the tree which makes assigning new IDs
bothersome. Putting them together should make the process less error-prone.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This API change means that virtio_net can tell how much capacity
remains for buffers.  It's necessarily fuzzy, since
VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors
in one, *if* we can kmalloc.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>

No need to put ethtool_ops in data, they should be const.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These are all drivers that don't touch real hardware.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If we run out of memory, use keventd to fill the buffer.  There's a
report of this happening: "Page allocation failures in guest",
Message-ID: <20090713115158.0a4892b0@mjolnir.ossman.eu>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>