linux-toradex.git/drivers/virtio, branch v2.6.34.3

virtio: fix oops on OOM

2010-08-02T17:29:51+00:00

commit 1fe9b6fef11771461e69ecd1bc8935a1c7c90cb5 upstream.

virtio ring was changed to return an error code on OOM,
but one caller was missed and still checks for vq->vring.num.
The fix is just to check for <0 error code.

Long term it might make sense to change goto add_head to
just return an error on oom instead, but let's apply
a minimal fix for 2.6.35.

Reported-by: Chris Mason 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell 
Tested-by: Chris Mason 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

virtio: return ENOMEM on out of memory

2010-08-02T17:29:17+00:00

commit 686d363786a53ed28ee875b84ef24e6d5126ef6f upstream.

add_buf returns ring size on out of memory,
this is not what devices expect.

Signed-off-by: Michael S. Tsirkin 
Acked-by: Amit Shah 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

virtio-pci: disable msi at startup

2010-08-02T17:29:16+00:00

commit b03214d559471359e2a85ae256686381d0672f29 upstream.

virtio-pci resets the device at startup by writing to the status
register, but this does not clear the pci config space,
specifically msi enable status which affects register
layout.

This breaks things like kdump when they try to use e.g. virtio-blk.

Fix by forcing msi off at startup. Since pci.c already has
a routine to do this, we export and use it instead of duplicating code.

Signed-off-by: Michael S. Tsirkin 
Tested-by: Vivek Goyal 
Acked-by: Jesse Barnes 
Cc: linux-pci@vger.kernel.org
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

virtio: Fix GFP flags passed from the virtio balloon driver

2010-04-22T14:34:05+00:00

The virtio balloon driver can dig into the reservation pools of the OS
to satisfy a balloon request.  This is not advisable and other balloon
drivers (drivers/xen/balloon.c) avoid this as well.

The patch also adds changes to avoid printing a warning if allocation
fails, since we retry after sometime anyway.

Signed-off-by: Balbir Singh 
Signed-off-by: Rusty Russell 
Cc: kvm 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

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

2010-03-30T13:02:32+00:00

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: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

virtio: set pci bus master enable bit

2010-03-02T11:41:14+00:00

As all virtio devices perform DMA, we
must enable bus mastering for them to be
spec compliant.

This patch fixes hotplug of virtio devices
with Linux guests and qemu 0.11-0.12.

Tested-by: Alexander Graf 
Signed-off-by: Michael S. Tsirkin

virtio: fix out of range array access

2010-02-28T18:39:11+00:00

I have observed the following error on virtio-net module unload:

------------[ cut here ]------------
WARNING: at kernel/irq/manage.c:858 __free_irq+0xa0/0x14c()
Hardware name: Bochs
Trying to free already-free IRQ 0
Modules linked in: virtio_net(-) virtio_blk virtio_pci virtio_ring
virtio af_packet e1000 shpchp aacraid uhci_hcd ohci_hcd ehci_hcd [last
unloaded: scsi_wait_scan]
Pid: 1957, comm: rmmod Not tainted 2.6.33-rc8-vhost #24
Call Trace:
 [] warn_slowpath_common+0x7c/0x94
 [] warn_slowpath_fmt+0x41/0x43
 [] ? __free_pages+0x5a/0x70
 [] __free_irq+0xa0/0x14c
 [] free_irq+0x3f/0x65
 [] vp_del_vqs+0x81/0xb1 [virtio_pci]
 [] virtnet_remove+0xda/0x10b [virtio_net]
 [] virtio_dev_remove+0x22/0x4a [virtio]
 [] __device_release_driver+0x66/0xac
 [] driver_detach+0x83/0xa9
 [] bus_remove_driver+0x91/0xb4
 [] driver_unregister+0x6c/0x74
 [] unregister_virtio_driver+0xe/0x10 [virtio]
 [] fini+0x15/0x17 [virtio_net]
 [] sys_delete_module+0x1c3/0x230
 [] ? old_ich_force_enable_hpet+0x117/0x164
 [] ? do_page_fault+0x29c/0x2cc
 [] sysenter_dispatch+0x7/0x27
---[ end trace 15e88e4c576cc62b ]---

The bug is in virtio-pci: we use msix_vector as array index to get irq
entry, but some vqs do not have a dedicated vector so this causes an out
of bounds access.  By chance, we seem to often get 0 value, which
results in this error.

Fix by verifying that vector is legal before using it as index.

Signed-off-by: Michael S. Tsirkin 
Acked-by: Anthony Liguori 
Acked-by: Shirley Ma 
Acked-by: Amit Shah

virtio: Initialize vq->data entries to NULL

2010-02-24T03:52:29+00:00

vq operations depend on vq->data[i] being NULL to figure out if the vq
entry is in use (since the previous patch).

We have to initialize them to NULL to ensure we don't work with junk
data and trigger false BUG_ONs.

Signed-off-by: Amit Shah 
Signed-off-by: Rusty Russell 
Cc: Shirley Ma

virtio: Add ability to detach unused buffers from vrings

2010-02-24T03:52:27+00:00

There's currently no way for a virtio driver to ask for unused
buffers, so it has to keep a list itself to reclaim them at shutdown.
This is redundant, since virtio_ring stores that information.  So
add a new hook to do this.

Signed-off-by: Shirley Ma 
Signed-off-by: Amit Shah 
Signed-off-by: Rusty Russell

virtio: use smp_XX barriers on SMP

2010-02-24T03:52:25+00:00

virtio is communicating with a virtual "device" that actually runs on
another host processor. Thus SMP barriers can be used to control
memory access ordering.

Where possible, we should use SMP barriers which are more lightweight than
mandatory barriers, because mandatory barriers also control MMIO effects on
accesses through relaxed memory I/O windows (which virtio does not use)
(compare specifically smp_rmb and rmb on x86_64).

We can't just use smp_mb and friends though, because
we must force memory ordering even if guest is UP since host could be
running on another CPU, but SMP barriers are defined to barrier() in
that configuration. So, for UP fall back to mandatory barriers instead.

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell