linux-toradex.git/drivers/xen/gntdev.c, branch v3.2.73

xen/gntdevt: Fix race condition in gntdev_release()

2015-10-13T02:46:01+00:00

commit 30b03d05e07467b8c6ec683ea96b5bffcbcd3931 upstream.

While gntdev_release() is called the MMU notifier is still registered
and can traverse priv->maps list even if no pages are mapped (which is
the case -- gntdev_release() is called after all). But
gntdev_release() will clear that list, so make sure that only one of
those things happens at the same time.

Signed-off-by: Marek Marczykowski-Górecki 
Signed-off-by: David Vrabel 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

xen/gntdev: convert priv->lock to a mutex

2015-10-13T02:46:01+00:00

commit 1401c00e59ea021c575f74612fe2dbba36d6a4ee upstream.

Unmapping may require sleeping and we unmap while holding priv->lock, so
convert it to a mutex.

Signed-off-by: David Vrabel 
Reviewed-by: Stefano Stabellini 
[bwh: Backported to 3.2:
 - Adjust context
 - Drop changes to functions we don't have]
Signed-off-by: Ben Hutchings

xen/gntdev: don't leak memory from IOCTL_GNTDEV_MAP_GRANT_REF

2012-11-16T16:47:00+00:00

commit a67baeb77375199bbd842fa308cb565164dd1f19 upstream.

map->kmap_ops allocated in gntdev_alloc_map() wasn't freed by
gntdev_put_map().

Add a gntdev_free_map() helper function to free everything allocated
by gntdev_alloc_map().

Signed-off-by: David Vrabel 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Ben Hutchings

xen/gntdev: do not set VM_PFNMAP

2012-05-11T12:13:53+00:00

commit e8e937be971d706061dc56220ff3605ab77622a7 upstream.

Since we are using the m2p_override we do have struct pages
corresponding to the user vma mmap'ed by gntdev.

Removing the VM_PFNMAP flag makes get_user_pages work on that vma.
An example test case would be using a Xen userspace block backend
(QDISK) on a file on NFS using O_DIRECT.

Signed-off-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Ben Hutchings

xen-gntdev: integer overflow in gntdev_alloc_map()

2011-11-16T17:13:46+00:00

The multiplications here can overflow resulting in smaller buffer
sizes than expected.  "count" comes from a copy_from_user().

Signed-off-by: Dan Carpenter 
Signed-off-by: Konrad Rzeszutek Wilk

Merge branch 'stable/cleanups-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

2011-11-07T04:13:34+00:00

* 'stable/cleanups-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: use static initializers in xen-balloon.c
  Xen: fix braces and tabs coding style issue in xenbus_probe.c
  Xen: fix braces coding style issue in xenbus_probe.h
  Xen: fix whitespaces,tabs coding style issue in drivers/xen/pci.c
  Xen: fix braces coding style issue in gntdev.c and grant-table.c
  Xen: fix whitespaces,tabs coding style issue in drivers/xen/events.c
  Xen: fix whitespaces,tabs coding style issue in drivers/xen/balloon.c

Fix up trivial whitespace-conflicts in
 drivers/xen/{balloon.c,pci.c,xenbus/xenbus_probe.c}

xen/gntdev: Fix sleep-inside-spinlock

2011-10-14T14:02:10+00:00

BUG: sleeping function called from invalid context at /local/scratch/dariof/linux/kernel/mutex.c:271
in_atomic(): 1, irqs_disabled(): 0, pid: 3256, name: qemu-dm
1 lock held by qemu-dm/3256:
 #0:  (&(&priv->lock)->rlock){......}, at: [] gntdev_ioctl+0x2bd/0x4d5
Pid: 3256, comm: qemu-dm Tainted: G        W   3.1.0-rc8+ #5
Call Trace:
 [] __might_sleep+0x131/0x135
 [] mutex_lock_nested+0x25/0x45
 [] free_xenballooned_pages+0x20/0xb1
 [] gntdev_put_map+0xa8/0xdb
 [] ? _raw_spin_lock+0x71/0x7a
 [] ? gntdev_ioctl+0x2bd/0x4d5
 [] gntdev_ioctl+0x31f/0x4d5
 [] ? check_events+0x12/0x20
 [] do_vfs_ioctl+0x488/0x4d7
 [] ? xen_restore_fl_direct_reloc+0x4/0x4
 [] ? lock_release+0x21c/0x229
 [] ? rcu_read_unlock+0x21/0x32
 [] sys_ioctl+0x47/0x6a
 [] system_call_fastpath+0x16/0x1b

gntdev_put_map tries to acquire a mutex when freeing pages back to the
xenballoon pool, so it cannot be called with a spinlock held. In
gntdev_release, the spinlock is not needed as we are freeing the
structure later; in the ioctl, only the list manipulation needs to be
under the lock.

Reported-and-Tested-By: Dario Faggioli 
Signed-off-by: Daniel De Graaf 
Signed-off-by: Konrad Rzeszutek Wilk

xen: modify kernel mappings corresponding to granted pages

2011-09-29T14:32:58+00:00

If we want to use granted pages for AIO, changing the mappings of a user
vma and the corresponding p2m is not enough, we also need to update the
kernel mappings accordingly.
Currently this is only needed for pages that are created for user usages
through /dev/xen/gntdev. As in, pages that have been in use by the
kernel and use the P2M will not need this special mapping.
However there are no guarantees that in the future the kernel won't
start accessing pages through the 1:1 even for internal usage.

In order to avoid the complexity of dealing with highmem, we allocated
the pages lowmem.
We issue a HYPERVISOR_grant_table_op right away in
m2p_add_override and we remove the mappings using another
HYPERVISOR_grant_table_op in m2p_remove_override.
Considering that m2p_add_override and m2p_remove_override are called
once per page we use multicalls and hypercall batching.

Use the kmap_op pointer directly as argument to do the mapping as it is
guaranteed to be present up until the unmapping is done.
Before issuing any unmapping multicalls, we need to make sure that the
mapping has already being done, because we need the kmap->handle to be
set correctly.

Signed-off-by: Stefano Stabellini 
[v1: Removed GRANT_FRAME_BIT usage]
Signed-off-by: Konrad Rzeszutek Wilk

xen: add an "highmem" parameter to alloc_xenballooned_pages

2011-09-29T13:56:52+00:00

Add an highmem parameter to alloc_xenballooned_pages, to allow callers to
request lowmem or highmem pages.

Fix the code style of free_xenballooned_pages' prototype.

Signed-off-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk

Xen: fix braces coding style issue in gntdev.c and grant-table.c

2011-07-26T17:31:58+00:00

This is a patch to the gntdev.c and grant-table.c files that fixed up
braces errors found by the checkpatch.pl tools.

Signed-off-by: Ruslan Pisarev 
Signed-off-by: Konrad Rzeszutek Wilk