vfio: Trivial Documentation correction

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
vfio: Fix virqfd release race

vfoi-pci supports a mechanism like KVM's irqfd for unmasking an
interrupt through an eventfd.  There are two ways to shutdown this
interface: 1) close the eventfd, 2) ioctl (such as disabling the
interrupt).  Both of these do the release through a workqueue,
which can result in a segfault if two jobs get queued for the same
virqfd.

Fix this by protecting the pointer to these virqfds by a spinlock.
The vfio pci device will therefore no longer have a reference to it
once the release job is queued under lock.  On the ioctl side, we
still flush the workqueue to ensure that any outstanding releases
are completed.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
rbd: drop dev reference on error in rbd_open()

If a read-only rbd device is opened for writing in rbd_open(), it
returns without dropping the just-acquired device reference.

Fix this by moving the read-only check before getting the reference.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
libceph: only kunmap kmapped pages

In write_partial_msg_pages(), pages need to be kmapped in order to
perform a CRC-32c calculation on them.  As an artifact of the way
this code used to be structured, the kunmap() call was separated
from the kmap() call and both were done conditionally.  But the
conditions under which the kmap() and kunmap() calls were made
differed, so there was a chance a kunmap() call would be done on a
page that had not been mapped.

The symptom of this was tripping a BUG() in kunmap_high() when
pkmap_count[nr] became 0.

Reported-by: Bryan K. Wright <bryan@virginia.edu>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
xen/boot: Disable NUMA for PV guests.

The hypervisor is in charge of allocating the proper "NUMA" memory
and dealing with the CPU scheduler to keep them bound to the proper
NUMA node. The PV guests (and PVHVM) have no inkling of where they
run and do not need to know that right now. In the future we will
need to inject NUMA configuration data (if a guest spans two or more
NUMA nodes) so that the kernel can make the right choices. But those
patches are not yet present.

In the meantime, disable the NUMA capability in the PV guest, which
also fixes a bootup issue. Andre says:

"we see Dom0 crashes due to the kernel detecting the NUMA topology not
by ACPI, but directly from the northbridge (CONFIG_AMD_NUMA).

This will detect the actual NUMA config of the physical machine, but
will crash about the mismatch with Dom0's virtual memory. Variation of
the theme: Dom0 sees what it's not supposed to see.

This happens with the said config option enabled and on a machine where
this scanning is still enabled (K8 and Fam10h, not Bulldozer class)

We have this dump then:
NUMA: Warning: node ids are out of bound, from=-1 to=-1 distance=10
Scanning NUMA topology in Northbridge 24
Number of physical nodes 4
Node 0 MemBase 0000000000000000 Limit 0000000040000000
Node 1 MemBase 0000000040000000 Limit 0000000138000000
Node 2 MemBase 0000000138000000 Limit 00000001f8000000
Node 3 MemBase 00000001f8000000 Limit 0000000238000000
Initmem setup node 0 0000000000000000-0000000040000000
  NODE_DATA [000000003ffd9000 - 000000003fffffff]
Initmem setup node 1 0000000040000000-0000000138000000
  NODE_DATA [0000000137fd9000 - 0000000137ffffff]
Initmem setup node 2 0000000138000000-00000001f8000000
  NODE_DATA [00000001f095e000 - 00000001f0984fff]
Initmem setup node 3 00000001f8000000-0000000238000000
Cannot find 159744 bytes in node 3
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff81d220e6>] __alloc_bootmem_node+0x43/0x96
Pid: 0, comm: swapper Not tainted 3.3.6 #1 AMD Dinar/Dinar
RIP: e030:[<ffffffff81d220e6>]  [<ffffffff81d220e6>] __alloc_bootmem_node+0x43/0x96
.. snip..
  [<ffffffff81d23024>] sparse_early_usemaps_alloc_node+0x64/0x178
  [<ffffffff81d23348>] sparse_init+0xe4/0x25a
  [<ffffffff81d16840>] paging_init+0x13/0x22
  [<ffffffff81d07fbb>] setup_arch+0x9c6/0xa9b
  [<ffffffff81683954>] ? printk+0x3c/0x3e
  [<ffffffff81d01a38>] start_kernel+0xe5/0x468
  [<ffffffff81d012cf>] x86_64_start_reservations+0xba/0xc1
  [<ffffffff81007153>] ? xen_setup_runstate_info+0x2c/0x36
  [<ffffffff81d050ee>] xen_start_kernel+0x565/0x56c
"

so we just disable NUMA scanning by setting numa_off=1.

CC: stable@vger.kernel.org
Reported-and-Tested-by: Andre Przywara <andre.przywara@amd.com>
Acked-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
tile: gxio iorpc numbering change for TRIO interface

An ABI numbering change was made in the hypervisor for Tilera's 4.1
MDE release (just shipped).  It's incompatible with the previous 4.0
release ABI numbering, so we track the new numbering going forward.
We plan to avoid modifying ABI numbering for these interfaces again.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client

Pull two ceph fixes from Sage Weil:
 "The first fixes a leak in the rbd setup error path, and the second
  fixes a more serious problem with mismatched kmap/kunmap that surfaced
  after the recent refactoring work."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  libceph: only kunmap kmapped pages
  rbd: drop dev reference on error in rbd_open()
Merge tag 'stable/for-linus-3.6-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull a Xen fix from Konrad Rzeszutek Wilk:
 "It is a bug-fix when we run the initial PV guest on a AMD K8 machine
  and have CONFIG_AMD_NUMA enabled and detect the NUMA topology from the
  Northbridge.

  We end up in the situation where the initial domain gets too much
  information and gets confused and crashes - the fix is to restrict the
  domain to get the information - and we do it by just disabling NUMA on
  the PV guest (the hypervisor is still able to do its proper NUMA
  allocations of guests).

  It is OK to disable the PV guest from accessing NUMA data as right now
  we do not inject any NUMA node information to the PV guests.  When we
  do get to that point, then this patch will have to be reverted."

 * Disable PV NUMA support as we do not do anything with it (yet) and it
   can cause bootup crashes on certain AMD machines.

* tag 'stable/for-linus-3.6-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/boot: Disable NUMA for PV guests.
Merge tag 'vfio-for-linus' of git://github.com/awilliam/linux-vfio

Pull vfio fixes from Alex Williamson:
 "VFIO doc update and virqfd race fix"

* tag 'vfio-for-linus' of git://github.com/awilliam/linux-vfio:
  vfio: Fix virqfd release race
  vfio: Trivial Documentation correction
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

Pull tile gxio ABI fix from Chris Metcalf:
 "This fixes a last-minute change in the Tilera hypervisor ABI for TRIO
  (PCI root complex) support.  We've locked in this ABI going forward
  and will make sure no further ABI changes like this occur."

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: gxio iorpc numbering change for TRIO interface
Larry the COW