sparc: Replace __get_cpu_var uses

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: sparclinux@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
clocksource: Replace __this_cpu_ptr with raw_cpu_ptr

One newly introduced __this_cpu_ptr should be raw_cpu_ptr.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
percpu: Remove __this_cpu_ptr

The __this_cpu_ptr macro is no longer in use so drop it.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
block,scsi: verify return pointer from blk_get_request

The blk-core dead queue checks introduce an error scenario to
blk_get_request that returns NULL if the request queue has been
shutdown. This affects the behavior for __GFP_WAIT callers, who should
verify the return value before dereferencing.

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Revert "powerpc: Replace __get_cpu_var uses"

This reverts commit 5828f666c069af74e00db21559f1535103c9f79a due to
build failure after merging with pending powerpc changes.

Link: http://lkml.kernel.org/g/20140827142243.6277eaff@canb.auug.org.au

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
dmaengine: Update documentation for inline wrapper

Commit 16052827d98fbc13c31ebad560af4bd53e2b4dd5 ("dmaengine/dma_slave:
introduce inline wrappers") introduced some wrappers, but there is still
a reference to the old function.

Update the documentation to use the wrapper, and add a missing "()" to a
function name.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
dma: rcar-audmapp: Fix for no corresponding slave ID

In case of no corresponding slave ID, the audmapp_set_slave() returns
-ENXIO same as sh_dmae_set_slave() of shdmac.c.
DMAEngine might return wrong channel without this patch

Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
Signed-off-by: Jun Watanabe <jun.watanabe.ue@renesas.com>,
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
dma: imx-sdma: Remove spurious __init annotation on sdma_probe()

We can't annotate probe functions as __init since binding can occur at
any time, not just during kernel init.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t

__get_cpu_var can paper over differences in the definitions of
cpumask_var_t and either use the address of the cpumask variable
directly or perform a fetch of the address of the struct cpumask
allocated elsewhere. This is important particularly when using per cpu
cpumask_var_t declarations because in one case we have an offset into
a per cpu area to handle and in the other case we need to fetch a
pointer from the offset.

This patch introduces a new macro

this_cpu_cpumask_var_ptr()

that is defined where cpumask_var_t is defined and performs the proper
actions. All use cases where __get_cpu_var is used with cpumask_var_t
are converted to the use of this_cpu_cpumask_var_ptr().

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
block,scsi: fixup blk_get_request dead queue scenarios

The blk_get_request function may fail in low-memory conditions or during
device removal (even if __GFP_WAIT is set). To distinguish between these
errors, modify the blk_get_request call stack to return the appropriate
ERR_PTR. Verify that all callers check the return status and consider
IS_ERR instead of a simple NULL pointer check.

For consistency, make a similar change to the blk_mq_alloc_request leg
of blk_get_request.  It may fail if the queue is dead, or the caller was
unwilling to wait.

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
bsg: fix potential error pointer dereference

Dan writes:

block/bsg.c:327 bsg_map_hdr() error: 'next_rq' dereferencing possible
ERR_PTR().

Fix this by setting next_rq to NULL, for the case where it can be
!= NULL but an error pointer.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
clk: mvebu: share locks between gate clocks

Refactor mvebu_clk_gating_setup() to use a common spinlock instead of a
unique lock for every instance of a struct clk_gating_ctrl object. This
will be used later for a separate mux clock type that shares a register
with gate clock types and needs to use the same lock to protect access
to the register.

Cc: Andrew Lunn <andrew@lunn.ch>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
clk: mvebu: powersave clock is a multiplexer

Kirkwood is unique among the mvebu SoCs for having a clock multiplexer
that feeds into the cpu. This multiplexer can select either the cpu pll
or the ddr clock as its input signal, allowing for a choice between
performance and power savings.

This patch introduces the code needed to register the clock multiplexer
on Kirkwood SoCs but does not include the clock data to actually
register the clock. That will be done in a follow-up patch which is
necessary to prevent breaking git bisect.

Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.

There must be an explit statement to modify the percpu variable after
the conversion of the sn_nodpda macro to use this_cpu_read.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Compile-tested-by: Guenter Roeck <linux@roeck-us.net>
cpufreq: kirkwood: use the powersave multiplexer

The powersave clock acts like a multiplexer for the cpu, selecting
either the clock signal derived from the cpu pll or from the ddr clock.
This patch changes powersave from a gate clock to a mux clock to better
reflect this behavior.

This is a cleaner approach whereby the frequency of the cpu always
matches the rate of powersave_clk. The cpufreq driver for the kirkwood
platform no longer must parse this behavior out of various calls to
clk_enable and clk_disable, but can instead simply select the parent cpu
it wants when changing rate. Likewise when requesting the cpu rate we
need only query powersave_clk's rate through the usual call to
clk_get_rate.

The new clock data and corresponding changes to the cpufreq driver are
combined into this single commit to avoid a git bisect issue where this
cpufreq driver fails to work properly between the commit that updates
the kirkwood clock driver and the commit that changes how the cpufreq
driver uses that clock.

Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
ARM: shmobile: r8a7794: document MSTP clock support

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
ARM: shmobile: r8a7794: document CPG clock support

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
clk: shmobile: add missing 0x0100 for SDCKCR

10cdfe9f327ab8d120cf6957e58c6203e3a53847
(clk: shmobile: Add R-Car Gen2 clocks support)
added R-Car Gen2 clock support via DT for v3.14.

But, cpg_sd01_div_table is missing
"0x0100: x 1/8" division ratio.
This patch fixes hidden bug.
It is based on R-Car H2 v0.7, R-Car M2 v0.9.

Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Reported-by: Yusuke Goda <yusuke.goda.sx@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
clk: rockchip: implement the fraction divider branch type

Rockchip SoCs may provide fraction dividers for some clocks, mostly for
i2s and uarts. In contrast to the other registers, these do not use
the hiword-mask paradigm, but instead split the register into the upper
16 bit for the nominator and the lower 16 bit for the denominator.

The common clock framework got a generic fractional divider clock type
recently that can accomodate this setting easily. All currently known
fraction dividers have a separate gate too, therefore implement the
divider as composite using the ops-struct from fractional_divider clock
and add the gate if necessary.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
clk: rockchip: make rockchip_clk_register_branch static

It is only used locally in clk/rockchip/clk.c and thus can be static.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>