COMPACTION enables MIGRATION, but MIGRATION spawns a warning if numa or
memhotplug aren't selected.  However MIGRATION doesn't depend on them.  I
guess it's just trying to be strict doing a double check on who's enabling
it, but it doesn't know that compaction also enables MIGRATION.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The pte_same check is reliable only if the swap entry remains pinned (by
the page lock on swapcache).  We've also to ensure the swapcache isn't
removed before we take the lock as try_to_free_swap won't care about the
page pin.

One of the possible impacts of this patch is that a KSM-shared page can
point to the anon_vma of another process, which could exit before the page
is freed.

This can leave a page with a pointer to a recycled anon_vma object, or
worse, a pointer to something that is no longer an anon_vma.

[riel@redhat.com: changelog help]
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Acked-by: NHugh Dickins <hughd@google.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the second if (reg & ...) test into the branch indicated by its
indentation.  The test was previously always executed after the if
containing that branch, but it was always false unless the if branch was
taken.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable braces4@
position p1,p2;
statement S1,S2;
@@

(
if (...) { ... }
|
if (...) S1@p1 S2@p2
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

if (p1[0].column == p2[0].column):
  cocci.print_main("branch",p1)
  cocci.print_secs("after",p2)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NChris Ball <cjb@laptop.org>
Cc: Pavel Pisa <ppisa@pikron.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If suspend called when kmmcd is doing host->ops->disable, as kmmcd already
increased host->en_dis_recurs to 1, the mmc_host_enable in suspend
function will return directly without increase the nesting_cnt, which will
cause the followed register access carried out to the disabled host.

mmc_suspend_host will enable host itself.  No need to enable host before
it.  Also works on kmmcd will get flushed in mmc_suspend_host, enable host
after it will be safe.  So make the mmc_host_enable after it.

[cjb: rebase against current Linus]
Signed-off-by: NEthan <ethan.too@gmail.com>
Signed-off-by: NChris Ball <cjb@laptop.org>
Acked-by: NAdrian Hunter <adrian.hunter@nokia.com>
Acked-by: NMadhusudhan Chikkature <madhu.cr@ti.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the following error:

at91_mci.c: In function 'at91_mci_sg_to_dma':
at91_mci.c:236: error: implicit declaration of function 'kmap_atomic'
at91_mci.c:236: error: 'KM_BIO_SRC_IRQ' undeclared (first use in this function)
at91_mci.c:236: error: (Each undeclared identifier is reported only once
at91_mci.c:236: error: for each function it appears in.)
at91_mci.c:236: warning: assignment makes pointer from integer without a cast
at91_mci.c:252: error: implicit declaration of function 'kunmap_atomic'
at91_mci.c: In function 'at91_mci_post_dma_read':
at91_mci.c:302: error: 'KM_BIO_SRC_IRQ' undeclared (first use in this function)
at91_mci.c:302: warning: assignment makes pointer from integer without a cast
at91_mci.c:317: error: implicit declaration of function 'flush_kernel_dcache_page'
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NChris Ball <cjb@laptop.org>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Andrew Victor <avictor.za@gmail.com>
Cc: Wolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes the following warning:

drivers/mmc/host/omap_hsmmc.c: In function 'omap_hsmmc_suspend':
drivers/mmc/host/omap_hsmmc.c:2275: warning: unused variable 'state'

Introduced by commit ID:

  commit 1a13f8fa
  Author: Matt Fleming <matt@console-pimps.org>
  Date:   Wed May 26 14:42:08 2010 -0700

      mmc: remove the "state" argument to mmc_suspend_host()

The unique usage of this var was removed there, and missed
removing the respective declaration aswell.
Signed-off-by: NSergio Aguirre <saaguirre@ti.com>
Signed-off-by: NChris Ball <cjb@laptop.org>
Acked-by: NMatt Fleming <matt@console-pimps.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

[cjb: fix line-wrapped patch]
Signed-off-by: NJiri Pinkava <jiri.pinkava@vscht.cz>
Signed-off-by: NChris Ball <cjb@laptop.org>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kunmap_atomic() takes the cookie, returned by the kmap_atomic() as its
argument and not the page address, used as an argument to kmap_atomic().
This patch fixes the compile error:

In file included from drivers/mmc/host/tmio_mmc.c:37:
drivers/mmc/host/tmio_mmc.h: In function 'tmio_mmc_kunmap_atomic':
drivers/mmc/host/tmio_mmc.h:192: error: negative width in bit-field '<anonymous>'
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: NEric Miao <eric.y.miao@gmail.com>
Tested-by: NMagnus Damm <damm@opensource.se>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Previously, it was possible for ack_mmc_irqs() to clear pending interrupt
bits in the CTL_STATUS register, even though the interrupt handler had not
been called.  This was because of a race that existed when doing a
read-modify-write sequence on CTL_STATUS.  After the read step in this
sequence, if an interrupt occurred (causing one of the bits in CTL_STATUS
to be set) the write step would inadvertently clear it.

Observed with the TMIO_STAT_RXRDY bit together with CMD53 on AR6002 and
BCM4318 SDIO cards in polled mode.

This patch eliminates this race by only writing to CTL_STATUS and clearing
the interrupts that were passed as an argument to ack_mmc_irqs()."

[matt@console-pimps.org: rewrote changelog]
Signed-off-by: NYusuke Goda <yusuke.goda.sx@renesas.com>
Acked-by: Magnus Damm <damm@opensource.se>"
Tested-by: Arnd Hannemann <arnd@arndnet.de>"
Acked-by: NIan Molton <ian@mnementh.co.uk>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: <linux-mmc@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add cgroup_attach_task_all()

The existing cgroup_attach_task_current_cg() API is called by a thread to
attach another thread to all of its cgroups; this is unsuitable for cases
where a privileged task wants to attach itself to the cgroups of a less
privileged one, since the call must be made from the context of the target
task.

This patch adds a more generic cgroup_attach_task_all() API that allows
both the source task and to-be-moved task to be specified.
cgroup_attach_task_current_cg() becomes a specialization of the more
generic new function.

[menage@google.com: rewrote changelog]
[akpm@linux-foundation.org: address reviewer comments]
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NAlex Williamson <alex.williamson@redhat.com>
Acked-by: NPaul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Ben Blum <bblum@google.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the left-over old ifdef for PG_uncached in /proc/kpageflags.  Now it's
used by x86, too.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The gcov-kernel infrastructure expects that each object file is loaded
only once.  This may not be true, e.g.  when loading multiple kernel
modules which are linked to the same object file.  As a result, loading
such kernel modules will result in incorrect gcov results while unloading
will cause a null-pointer dereference.

This patch fixes these problems by changing the gcov-kernel infrastructure
so that multiple profiling data sets can be associated with one debugfs
entry.  It applies to 2.6.36-rc1.
Signed-off-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Reported-by: NWerner Spies <werner.spies@thalesgroup.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kexec tools has been moved to http://kernel.org/pub/linux/utils/kernel/kexec/
as user-space code shouldn't be in /pub/linux/kernel
Signed-off-by: NSimon Horman <horms@verge.net.au>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

commit c2c6ca41 (direct-io: do not merge logically non-contiguous requests)
introduced a bug whereby all O_DIRECT I/Os were submitted a page at a time
to the block layer.  The problem is that the code expected
dio->block_in_file to correspond to the current page in the dio.  In fact,
it corresponds to the previous page submitted via submit_page_section.
This was purely an oversight, as the dio->cur_page_fs_offset field was
introduced for just this purpose.  This patch simply uses the correct
variable when calculating whether there is a mismatch between contiguous
logical blocks and contiguous physical blocks (as described in the
comments).

I also switched the if conditional following this check to an else if, to
ensure that we never call dio_bio_submit twice for the same dio (in
theory, this should not happen, anyway).

I've tested this by running blktrace and verifying that a 64KB I/O was
submitted as a single I/O.  I also ran the patched kernel through
xfstests' aio tests using xfs, ext4 (with 1k and 4k block sizes) and btrfs
and verified that there were no regressions as compared to an unpatched
kernel.
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Acked-by: NJosef Bacik <jbacik@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: <stable@kernel.org>		[2.6.35.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Added missing axis-mapping for HP ProBook 532x and HP Mini 5102.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

bob.picco@hp.com doesn't work any more and Bob says that he's unlikely to
work on hpet.c in the future.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NBob Picco <bpicco@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Much (but not all) of the RTC state is kept in the RTC peripheral which
has its own power domain.  Periodically (1 HZ), that state is synced from
one power domain to the other (peripheral->core).  When we are resuming,
we need to wait for the sync to occur so that we don't get a mismatch of
reading undefined state in the rest of the driver.

Further, once the externally maintained bits have been synced back into
the core, we then need to restore the bits maintained in the core.  In our
particular case, that is just the write completion interrupt bit.

If we don't do any of this, working with the RTC causes ~5 second delays
from time to time after waking up due to the write completion interrupt
never firing.
Reported-by: NMichael Dean <mdean@aeronix.com>
Reported-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The int_clear helper takes a bitmask of interrupts to keep, not to
disable.  When suspending without wakeup enabled, we want to disable
all interrupts, so use 0 (keep none) instead of -1 (keep all).
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some macro parameter references inside typeof() operator are not enclosed
with parenthesis.  It should be safer to add them.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Acked-by: NStefani Seibold <stefani@seibold.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The introduction of support for SD combo cards breaks the initialization
of all CSR SDIO chips.  The GO_IDLE (CMD0) in mmc_sd_get_cid() causes CSR
chips to be reset (this is non-standard behavior).

When initializing an SDIO card check for a combo card by using the memory
present bit in the R4 response to IO_SEND_OP_COND (CMD5).  This avoids the
call to mmc_sd_get_cid() on an SDIO-only card.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Acked-by: NMichal Mirolaw <mirq-linux@rere.qmqm.pl>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* master.kernel.org:/home/rmk/linux-2.6-arm: (30 commits)
  ARM: Update mach-types
  ARM: Partially revert "Auto calculate ZRELADDR and provide option for exceptions"
  ARM: Ensure PTE modifications via dma_alloc_coherent are visible
  ARM: 6359/1: ep93xx: move clock initialization earlier
  Revert "[ARM] pxa: remove now unnecessary dma_needs_bounce()"
  ARM: 6352/1: perf: fix event validation
  ARM: 6344/1: Mark CPU_32v6K as depended on CPU_V7
  ARM: 6343/1: wire up fanotify and prlimit64 syscalls on ARM
  ARM: 6330/1: perf: reword comments relating to perf_event_do_pending
  ARM: pxa168fb: fix section mismatch
  ARM: pxa: Make id const in pwm_probe()
  ARM: pxa: fix CI_HSYNC and CI_VSYNC MFP defines for pxa300
  ARM: pxa: remove __init from cpufreq_driver->init()
  ARM: imx: set cache line size to 64 bytes for i.MX5
  mx5/clock: fix clear bit fields issue in _clk_ccgr_disable function
  mxc/tzic: add base address when accessing TZIC registers
  ARM: mach-shmobile: ap4evb: fix write protect for SDHI1
  ARM: mach-shmobile: ap4evb: modify FSI2 ID
  ARM: mach-shmobile: do not enable the PLLC2 clock on init
  ARM: mach-shmobile: Clock framework comment fix
  ...

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Partially revert e69edc79, which introduced automatic zreladdr
support.  The change in the way the manual definition is defined
seems to be error and conflict prone.  Go back to the original way
we were handling this for the time being, while keeping the automatic
zreladdr facility.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

lg_lock_global() currently only acquires spinlocks for online CPUs, but
it's meant to lock all possible CPUs.  Lglock-protected resources may be
associated with removed CPUs - and, indeed, that could happen with the
per-superblock open files lists.

At Nick's suggestion, change for_each_online_cpu() to
for_each_possible_cpu() to protect accesses to those resources.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: NNick Piggin <npiggin@kernel.dk>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

So it can be used by all that need to check for that.
Signed-off-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  RDMA/nes: Fix hang with modified FIN handling on A0 cards
  RDMA/nes: Change state to closing after FIN
  RDMA/nes: Fix double CLOSE event indication crash
  RDMA/nes: Write correct register write to set TX pause param
  RDMA/cxgb3: Don't exceed the max HW CQ depth

* 'fixes' of git://oss.oracle.com/git/tma/linux-2.6:
  ocfs2: Fix orphan add in ocfs2_create_inode_in_orphan
  ocfs2: split out ocfs2_prepare_orphan_dir() into locking and prep functions
  ocfs2: allow return of new inode block location before allocation of the inode
  ocfs2: use ocfs2_alloc_dinode_update_counts() instead of open coding
  ocfs2: split out inode alloc code from ocfs2_mknod_locked
  Ocfs2: Fix a regression bug from mainline commit(6b933c8e).
  ocfs2: Fix deadlock when allocating page
  ocfs2: properly set and use inode group alloc hint
  ocfs2: Use the right group in nfs sync check.
  ocfs2: Flush drive's caches on fdatasync
  ocfs2: make __ocfs2_page_mkwrite handle file end properly.
  ocfs2: Fix incorrect checksum validation error
  ocfs2: Fix metaecc error messages

Changing state to CLOSING when FIN is received causes A0 cards to
hang.  Fix this by checking for A0 cards in FIN handling.
Signed-off-by: NFaisal Latif <faisal.latif@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

When the driver receives an AE for FIN received, it closes the
connection without changing the state of the connection in the
hardware to closing.  By changing the state to closing, hardware will
do a normal close sequence.
Signed-off-by: NFaisal Latif <faisal.latif@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

During a stress testing in a large cluster, multiple close event are
detected and BUG() is hit in the iWARP core.  The cause is that the
active node gave up while waiting for an MPA response from the peer
and tried to close the connection by sending RST.  The passive node
driver receives the RST but is waiting for MPA response from the user.
When the MPA accept is received, the driver offloads the connection
and sends a CLOSE event.  The driver gets an AE indicating RESET
received and also sends a CLOSE event, hitting a BUG().

Fix this by correcting RESET handling and sending CLOSE events.
Signed-off-by: NFaisal Latif <faisal.latif@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Setting TX pause param writes to the wrong register location causing
the adapter to hang.  Correct the define used to write the reigster.

Addresses: https://bugs.openfabrics.org/show_bug.cgi?id=2116Reported-by: NShiri Franchi <shirif@voltaire.com>
Signed-off-by: NChien Tung <chien.tin.tung@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: i8042 - fix device removal on unload
  Input: bcm5974 - adjust major/minor to scale
  Input: MT - initialize slots to unused
  Input: use PIT_TICK_RATE in vt beep ioctl
  Input: wacom - fix mousewheel handling for old wacom tablets

Merge branch 'semaphore-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'semaphore-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  semaphore: Add DEFINE_SEMAPHORE

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, mcheck: Avoid duplicate sysfs links/files for thresholding banks
  io-mapping: Fix the address space annotations
  x86: Fix the address space annotations of iomap_atomic_prot_pfn()
  x86, mm: Fix CONFIG_VMSPLIT_1G and 2G_OPT trampoline
  x86, hwmon: Fix unsafe smp_processor_id() in thermal_throttle_add_dev

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  gcc-4.6: kernel/*: Fix unused but set warnings
  mutex: Fix annotations to include it in kernel-locking docbook
  pid: make setpgid() system call use RCU read-side critical section
  MAINTAINERS: Add RCU's public git tree

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf, x86: Try to handle unknown nmis with an enabled PMU
  perf, x86: Fix handle_irq return values
  perf, x86: Fix accidentally ack'ing a second event on intel perf counter
  oprofile, x86: fix init_sysfs() function stub
  lockup_detector: Sync touch_*_watchdog back to old semantics
  tracing: Fix a race in function profile
  oprofile, x86: fix init_sysfs error handling
  perf_events: Fix time tracking for events with pid != -1 and cpu != -1
  perf: Initialize callchains roots's childen hits
  oprofile: fix crash when accessing freed task structs

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix lock annotations
  fuse: flush background queue on connection close

Dave Hylands reports:
| We've observed a problem with dma_alloc_writecombine when the system
| is under heavy load (heavy bus traffic).  We've managed to reduce the
| problem to the following snippet, which is run from a kthread in a
| continuous loop:
|
|   void *virtAddr;
|   dma_addr_t physAddr;
|   unsigned int numBytes = 256;
|
|   for (;;) {
|       virtAddr = dma_alloc_writecombine(NULL,
|             numBytes, &physAddr, GFP_KERNEL);
|       if (virtAddr == NULL) {
|          printk(KERN_ERR "Running out of memory\n");
|          break;
|       }
|
|       /* access DMA memory allocated */
|       tmp = virtAddr;
|       *tmp = 0x77;
|
|       /* free DMA memory */
|       dma_free_writecombine(NULL,
|             numBytes, virtAddr, physAddr);
|
|         ...sleep here...
|     }
|
| By itself, the code will run forever with no issues. However, as we
| increase our bus traffic (typically using DMA) then the *tmp = 0x77
| line will eventually cause a page fault. If we add a small delay (a
| few microseconds) before the *tmp = 0x77, then we don't see a page
| fault, even under heavy load.

A dsb() is required after modifying the PTE entries to ensure that they
will always be visible.  Add this dsb().
Reported-by: NDave Hylands <dhylands@gmail.com>
Tested-by: NDave Hylands <dhylands@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>