msm: kgsl: Take the pagetable reference count only when needed

There could be a race condition where one thread is iterating
over ptlist inside kgsl_get_pagetable() with spinlock acquired
and going to call kref_put(). At the same time another thread is
inside kgsl_put_pagetable() without any spinlock calls kref_put()
and returns without calling kgsl_destroy_pagetable(). The decrement
of refcount by second thread leads to a situation where first thread
enters kgsl_destroy_pagetable_locked() and hence destroying the pt
node from list. This causes the destroyed pt node's next and prev
pointers set to POISON value resulting in kernel panic while executing
next iteration of ptlist.

Taking pt refcount while iterating over ptlist should be avoided if the
spinlock is already held and the pt is not returned to the caller. In
kgsl_get_pagetable(), since the loop is already holding the mutex, it
is safe to look at pt before taking a reference.

CRs-Fixed: 661374
Change-Id: Ide1f57cc1eb3cbf66fa399b6b72491755b999c7a
Signed-off-by: Prabhat Awasthi <pawasthi@codeaurora.org>
xhci: correct burst count field for isoc transfers on 1.0 xhci hosts

The transfer burst count (TBC) field in xhci 1.0 hosts should be set
to the number of bursts needed to transfer all packets in a isoc TD.
Supported values are 0-2 (1 to 3 bursts per service interval).

Formula for TBC calculation is given in xhci spec section 4.11.2.3:
TBC = roundup( Transfer Descriptor Packet Count / Max Burst Size +1 ) - 1

This patch should be applied to stable kernels since 3.0 that contain
the commit 5cd43e33b9519143f06f507dd7cbee6b7a621885
"xhci 1.0: Set transfer burst count field."

Cc: stable@vger.kernel.org # 3.0
Suggested-by: ShiChun Ma <masc2008@qq.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xhci: Fix runtime suspended xhci from blocking system suspend.

The system suspend flow as following:
1, Freeze all user processes and kenrel threads.

2, Try to suspend all devices.

2.1, If pci device is in RPM suspended state, then pci driver will try
to resume it to RPM active state in the prepare stage.

2.2, xhci_resume function calls usb_hcd_resume_root_hub to queue two
workqueue items to resume usb2&usb3 roothub devices.

2.3, Call suspend callbacks of devices.

2.3.1, All suspend callbacks of all hcd's children, including
roothub devices are called.

2.3.2, Finally, hcd_pci_suspend callback is called.

Due to workqueue threads were already frozen in step 1, the workqueue
items can't be scheduled, and the roothub devices can't be resumed in
this flow. The HCD_FLAG_WAKEUP_PENDING flag which is set in
usb_hcd_resume_root_hub won't be cleared. Finally,
hcd_pci_suspend will return -EBUSY, and system suspend fails.

The reason why this issue doesn't show up very often is due to that
choose_wakeup will be called in step 2.3.1. In step 2.3.1, if
udev->do_remote_wakeup is not equal to device_may_wakeup(&udev->dev), then
udev will resume to RPM active for changing the wakeup settings. This
has been a lucky hit which hides this issue.

For some special xHCI controllers which have no USB2 port, then roothub
will not match hub driver due to probe failed. Then its
do_remote_wakeup will be set to zero, and we won't be as lucky.

xhci driver doesn't need to resume roothub devices everytime like in
the above case. It's only needed when there are pending event TRBs.

This patch should be back-ported to kernels as old as 3.2, that
contains the commit f69e3120df82391a0ee8118e0a156239a06b2afb
"USB: XHCI: resume root hubs when the controller resumes"

Cc: stable@vger.kernel.org # 3.2
Signed-off-by: Wang, Yu <yu.y.wang@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
[use readl() instead of removed xhci_readl(), reword commit message -Mathias]
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Shit! Busybox says kernel too old
Revert "mm: fix crashes from mbind() merging vmas"

This reverts commit 432ba8614db4f7e89c71c85f251d8287790e08a0.
mm: fix crashes from mbind() merging vmas

commit d05f0cdcbe6388723f1900c549b4850360545201 upstream.

In v2.6.34 commit 9d8cebd4bcd7 ("mm: fix mbind vma merge problem")
introduced vma merging to mbind(), but it should have also changed the
convention of passing start vma from queue_pages_range() (formerly
check_range()) to new_vma_page(): vma merging may have already freed
that structure, resulting in BUG at mm/mempolicy.c:1738 and probably
worse crashes.

Fixes: 9d8cebd4bcd7 ("mm: fix mbind vma merge problem")
Reported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>