Commit 6aa85a5a (omap4: 4430sdp:
enable the ehci port on 4430SDP) added code to enable EHCI
support on 4430sdp board.

Looks like the ULPI pin does not seem to be muxed properly on ES1.0
SDP and this causes the system to reboot when the ULPI PHY is
enabled.

Fix this by muxing the pin, this is the same setting for
both ES1.0 and ES2.0. Also add checking for gpio_request.

Cc: Keshava Munegowda <keshava_mgowda@ti.com
Signed-off-by: Tony Lindgren <tony@atomide.com>

TFP410 DVI chip is used to provide display out.
This chip is controlled by 2 lines:
LDO which supplies the power is controlled over gpio + 2
and the enable of the chip itself is done over gpio + 1
NOTE: the LDO is necessary for LED, serial blocks as well.

gpio + 1 was used to sense USB overcurrent in vanilla beagle.

Without this fix, the display would not function as the LDO
remains shut down.

[nm@ti.com: split up, added descriptive changelogs]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Koen Kooi <koen@beagleboard.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

This patch adds omap_reserve functionality to board-igep0030.c.

This patch is in similar lines to commit id 71ee7dad, from
Russell king

Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

GPIO reset line for Beagle XM is different from vanilla beagle
so we populate it as part of gpio update routine.

This in part fixes the issue of display not functioning on beagle XM
platform.

[nm@ti.com: split up, added descriptive changelogs]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Koen Kooi <koen@beagleboard.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

EHCI enable power pin is inverted (active high) in comparison
to vanilla beagle which is active low. Handle this case conditionally.

Without this fix, Beagle XM 4 port EHCI will not function and no
networking will be available

[nm@ti.com: split up, added descriptive changelogs]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Koen Kooi <koen@beagleboard.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

Support twl4030 keypad and gpio keys on IGEP v2.
Signed-off-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

The second MMC channel (used by the WLAN/BT module) is not linked to
power regulator. This causes the WLAN/BT module to fail being detected if
CONFIG_REGULATOR_DUMMY is not set.

This patch adds the two regulators that actually feed the WLAN/BT module
(1v8 from the TWL4030 VIO LDO, and a fixed 3v3). With that patch, the
second channel is properly detected.

Also change vmmc1 to use symbolic names instead of direct device
reference.
Signed-off-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Acked-by: Marc Zyngier <maz@misterjones.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

The OMAP3 IGEP module has one EHCI interface on board using
USB2HS port. GPIO183 is used as PHY reset.
Signed-off-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

At latest mainline commit 0c21e3aa,  omap2plus build is broken. This
patch is trivial fix for the missed usb clock node for CK_3430ES2PLUS
flag update.

 CHK     include/generated/compile.h
  CC      arch/arm/mach-omap2/clock3xxx_data.o
arch/arm/mach-omap2/clock3xxx_data.c:3289: error: 'CK_3430ES2' undeclared
here (not in a function)
make[1]: *** [arch/arm/mach-omap2/clock3xxx_data.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Anand Gadiyar <gadiyar@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
[tony@atomide.com: updated mask to include CK_36XX]
Signed-off-by: Tony Lindgren <tony@atomide.com>

The SMSC 3320 USB PHY on the OMAP4 Pandaboard needs a 19.2 MHz
reference clock. This clock is provided from the OMAP4's fref_clk3
pad.

Recent changes to clock44xx_data.c made the clock framework aware
of the existence of these fref_clk[i] lines. If the option
CONFIG_OMAP_RESET_CLOCKS is enabled in the kernel, then the
clock framework will turn these clocks off during bootup.

Explicitly request and keep this clock enabled at init for the
Pandaboard, so that the PHY receives this clock at all times.
Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

omap2plus_defocnfig build breaks when customised with only ARCH_OMAP4
selected. This is because common files make references to the functions
which are defined only for omap2xxx and omap3xxx.

 LD      .tmp_vmlinux1
arch/arm/mach-omap2/built-in.o: In function `pm_dbg_regset_store':
arch/arm/mach-omap2/pm-debug.c:335: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/built-in.o: In function `omap2_pm_dump':
arch/arm/mach-omap2/pm-debug.c:121: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/pm-debug.c:123: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/pm-debug.c:124: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/pm-debug.c:125: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/built-in.o: In function `omap_prcm_arch_reset':
arch/arm/mach-omap2/prcm.c:106: undefined reference to `omap2_prm_set_mod_reg_bits'
arch/arm/mach-omap2/prcm.c:108: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/built-in.o: In function `omap_prcm_get_reset_sources':
arch/arm/mach-omap2/prcm.c:53: undefined reference to `omap2_prm_read_mod_reg'
arch/arm/mach-omap2/built-in.o: In function `clkdm_clear_all_wkdeps':
arch/arm/mach-omap2/clockdomain.c:545: undefined reference to `omap2_prm_clear_mod_reg_bits'
arch/arm/mach-omap2/built-in.o: In function `clkdm_del_wkdep':
arch/arm/mach-omap2/clockdomain.c:475: undefined reference to `omap2_prm_clear_mod_reg_bits'
arch/arm/mach-omap2/built-in.o: In function `clkdm_read_wkdep':
arch/arm/mach-omap2/clockdomain.c:511: undefined reference to `omap2_prm_read_mod_bits_shift'
arch/arm/mach-omap2/built-in.o: In function `clkdm_add_wkdep':
arch/arm/mach-omap2/clockdomain.c:440: undefined reference to `omap2_prm_set_mod_reg_bits'
make: *** [.tmp_vmlinux1] Error 1

This patch adds stubs for these functions so that build continues to work.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

CC      arch/arm/mach-omap2/omap_hwmod_common_data.o
In file included from arch/arm/plat-omap/include/plat/omap_hwmod.h:38,
                 from arch/arm/mach-omap2/omap_hwmod_common_data.c:20:
arch/arm/plat-omap/include/plat/voltage.h: In function 'omap_voltage_late_init':
arch/arm/plat-omap/include/plat/voltage.h:145: error: 'EINVAL' undeclared (first use in this function)
arch/arm/plat-omap/include/plat/voltage.h:145: error: (Each undeclared identifier is reported only once
arch/arm/plat-omap/include/plat/voltage.h:145: error: for each function it appears in.)
make[1]: *** [arch/arm/mach-omap2/omap_hwmod_common_data.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2

The error is reported when omap2plus_defconfig built with CONFIG_PM disabled
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Thara Gopinath <thara@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

LD      init/built-in.o
LD      .tmp_vmlinux1
arch/arm/mach-omap2/built-in.o: In function `omap2_set_init_voltage':
arch/arm/mach-omap2/pm.c:181: undefined reference to `omap_voltage_domain_lookup'
arch/arm/mach-omap2/built-in.o: In function `omap4_twl_init':
arch/arm/mach-omap2/omap_twl.c:244: undefined reference to `omap_voltage_domain_lookup'
arch/arm/mach-omap2/omap_twl.c:247: undefined reference to `omap_voltage_domain_lookup'
arch/arm/mach-omap2/omap_twl.c:250: undefined reference to `omap_voltage_domain_lookup'
make: *** [.tmp_vmlinux1] Error 1

The error is reported when omap2plus_defconfig built with CONFIG_PM disabled
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Thara Gopinath <thara@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

Fix below build warnings

 CC      arch/arm/mach-omap2/common.o
  CC      arch/arm/mach-omap2/gpio.o
In file included from arch/arm/plat-omap/include/plat/omap_hwmod.h:38,
                 from arch/arm/mach-omap2/gpio.c:25:
arch/arm/plat-omap/include/plat/voltage.h: In function 'omap_voltage_register_pmic':
arch/arm/plat-omap/include/plat/voltage.h:137: warning: no return statement in function returning non-void
  CC      arch/arm/mach-omap2/dma.o
In file included from arch/arm/plat-omap/include/plat/omap_hwmod.h:38,
                 from arch/arm/mach-omap2/dma.c:32:
arch/arm/plat-omap/include/plat/voltage.h: In function 'omap_voltage_register_pmic':
arch/arm/plat-omap/include/plat/voltage.h:137: warning: no return statement in function returning non-void
  CC      arch/arm/mach-omap2/wd_timer.o
In file included from arch/arm/plat-omap/include/plat/omap_hwmod.h:38,
                 from arch/arm/mach-omap2/wd_timer.c:15:
arch/arm/plat-omap/include/plat/voltage.h: In function 'omap_voltage_register_pmic':
arch/arm/plat-omap/include/plat/voltage.h:137: warning: no return statement in function returning non-void
  CC      arch/arm/mach-omap2/prm44xx.o
  CC      arch/arm/mach-omap2/omap_hwmod.o
In file included from arch/arm/plat-omap/include/plat/omap_hwmod.h:38,
                 from arch/arm/mach-omap2/omap_hwmod.c:145:
arch/arm/plat-omap/include/plat/voltage.h: In function 'omap_voltage_register_pmic':
arch/arm/plat-omap/include/plat/voltage.h:137: warning: no return statement in function returning non-void
  CC      arch/arm/mach-omap2/omap_hwmod_common_data.o
In file included from arch/arm/plat-omap/include/plat/omap_hwmod.h:38,
                 from arch/arm/mach-omap2/omap_hwmod_common_data.c:20:
arch/arm/plat-omap/include/plat/voltage.h: In function 'omap_voltage_register_pmic':
arch/arm/plat-omap/include/plat/voltage.h:137: warning: no return statement in function returning non-void

The error is reported when omap2plus_defconfig built with CONFIG_PM disabled
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Thara Gopinath <thara@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

struct clockdomain member clktrctrl_mask is available for only for OMAP2
and OMAP3 architectures. Technially it is also used only for these archs
but this breaks the build with custom OMAP4 configuration.

 CC      arch/arm/mach-omap2/clockdomain.o
arch/arm/mach-omap2/clockdomain.c: In function '_enable_hwsup':
arch/arm/mach-omap2/clockdomain.c:251: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c:254: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c: In function '_disable_hwsup':
arch/arm/mach-omap2/clockdomain.c:277: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c:280: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c: In function 'omap2_clkdm_sleep':
arch/arm/mach-omap2/clockdomain.c:744: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c: In function 'omap2_clkdm_wakeup':
arch/arm/mach-omap2/clockdomain.c:789: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c: In function 'omap2_clkdm_clk_enable':
arch/arm/mach-omap2/clockdomain.c:922: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c:926: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c: In function 'omap2_clkdm_clk_disable':
arch/arm/mach-omap2/clockdomain.c:994: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
arch/arm/mach-omap2/clockdomain.c:998: error: 'struct clockdomain' has no member named 'clktrctrl_mask'
make[1]: *** [arch/arm/mach-omap2/clockdomain.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2

Fix the build break by dropping the #ifdef as suggested by Paul Walmsley
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

Instead of accessing the irq_desc array directly
we can use irq_to_desc(irq). That will allow us to,
if wanted, select SPARSE_IRQ and irq_descs will be
added to a radix tree, instead of a array.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

omap_pm_runtime_suspend and omap_pm_runtime_resume are used
as function pointers and does not really need to be exposed
to the world.

Fixes sparse warnings:
arch/arm/mach-omap2/pm_bus.c:23:5: warning: symbol 'omap_pm_runtime_suspend' was not declared. Should it be static?
arch/arm/mach-omap2/pm_bus.c:40:5: warning: symbol 'omap_pm_runtime_resume' was not declared. Should it be static?
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

In case on OMAP2+ we call set_24xx_gpio_triggering() instead of
updating reg and l values. However, at the end of the function we
perform a write:

	__raw_writel(l, reg);

So on OMAP2+ we end up writing 0 to the bank->base which is not
correct (typically this points to GPIO_REVISION register).

Fix this by returning immediately after call to
set_24xx_gpio_triggering().
Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

twl_init functions are declared in pm.h and used in pm.c
pm.h header defining the protos need to be included to
ensure that omap_twl.c has consistent function definition.
This fixes sparse warning:
arch/arm/mach-omap2/omap_twl.c:237:12: warning: symbol 'omap4_twl_init' was not declared. Should it be static?
arch/arm/mach-omap2/omap_twl.c:256:12: warning: symbol 'omap3_twl_init' was not declared. Should it be static?
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

The uv_to_vsel, vsel_to_uv functions don't need to be exposed to the
world as they are used as function pointers. make them static.

Fixes sparse warnings:
arch/arm/mach-omap2/omap_twl.c:63:15: warning: symbol 'twl4030_vsel_to_uv' was not declared. Should it be static?
arch/arm/mach-omap2/omap_twl.c:68:4: warning: symbol 'twl4030_uv_to_vsel' was not declared. Should it be static?
arch/arm/mach-omap2/omap_twl.c:73:15: warning: symbol 'twl6030_vsel_to_uv' was not declared. Should it be static?
arch/arm/mach-omap2/omap_twl.c:105:4: warning: symbol 'twl6030_uv_to_vsel' was not declared. Should it be static?
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

omap_enable_smartreflex_on_init is meant to be used by boards
which would like to have SR enabled by default on the platform, while
omap_devinit_smartreflex is used by pm code, the protos are defined
in pm.h. This header should be included to ensure that sr_device
function definitions match the prototypes.

including pm.h fixes the sparse warnings (with CONFIG_OMAP_SMARTREFLEX=y):
arch/arm/mach-omap2/sr_device.c:138:13: warning: symbol 'omap_enable_smartreflex_on_init' was not declared. Should it be static?
arch/arm/mach-omap2/sr_device.c:143:12: warning: symbol 'omap_devinit_smartreflex' was not declared. Should it be static?
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

* 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (144 commits)
  USB: add support for Dream Cheeky DL100B Webmail Notifier (1d34:0004)
  USB: serial: ftdi_sio: add support for TIOCSERGETLSR
  USB: ehci-mxc: Setup portsc register prior to accessing OTG viewport
  USB: atmel_usba_udc: fix freeing irq in usba_udc_remove()
  usb: ehci-omap: fix tll channel enable mask
  usb: ohci-omap3: fix trivial typo
  USB: gadget: ci13xxx: don't assume that PAGE_SIZE is 4096
  USB: gadget: ci13xxx: fix complete() callback for no_interrupt rq's
  USB: gadget: update ci13xxx to work with g_ether
  USB: gadgets: ci13xxx: fix probing of compiled-in gadget drivers
  Revert "USB: musb: pm: don't rely fully on clock support"
  Revert "USB: musb: blackfin: pm: make it work"
  USB: uas: Use GFP_NOIO instead of GFP_KERNEL in I/O submission path
  USB: uas: Ensure we only bind to a UAS interface
  USB: uas: Rename sense pipe and sense urb to status pipe and status urb
  USB: uas: Use kzalloc instead of kmalloc
  USB: uas: Fix up the Sense IU
  usb: musb: core: kill unneeded #include's
  DA8xx: assign name to MUSB IRQ resource
  usb: gadget: g_ncm added
  ...

Manually fix up trivial conflicts in USB Kconfig changes in:
	arch/arm/mach-omap2/Kconfig
	arch/sh/Kconfig
	drivers/usb/Kconfig
	drivers/usb/host/ehci-hcd.c
and annoying chip clock data conflicts in:
	arch/arm/mach-omap2/clock3xxx_data.c
	arch/arm/mach-omap2/clock44xx_data.c

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (147 commits)
  [SCSI] arcmsr: fix write to device check
  [SCSI] lpfc: lower stack use in lpfc_fc_frame_check
  [SCSI] eliminate an unnecessary local variable from scsi_remove_target()
  [SCSI] libiscsi: use bh locking instead of irq with session lock
  [SCSI] libiscsi: do not take host lock in queuecommand
  [SCSI] be2iscsi: fix null ptr when accessing task hdr
  [SCSI] be2iscsi: fix gfp use in alloc_pdu
  [SCSI] libiscsi: add more informative failure message during iscsi scsi eh
  [SCSI] gdth: Add missing call to gdth_ioctl_free
  [SCSI] bfa: remove unused defintions and misc cleanups
  [SCSI] bfa: remove inactive functions
  [SCSI] bfa: replace bfa_assert with WARN_ON
  [SCSI] qla2xxx: Use sg_next to fetch next sg element while walking sg list.
  [SCSI] qla2xxx: Fix to avoid recursive lock failure during BSG timeout.
  [SCSI] qla2xxx: Remove code to not reset ISP82xx on failure.
  [SCSI] qla2xxx: Display mailbox register 4 during 8012 AEN for ISP82XX parts.
  [SCSI] qla2xxx: Don't perform a BIG_HAMMER if Get-ID (0x20) mailbox command fails on CNAs.
  [SCSI] qla2xxx: Remove redundant module parameter permission bits
  [SCSI] qla2xxx: Add sysfs node for displaying board temperature.
  [SCSI] qla2xxx: Code cleanup to remove unwanted comments and code.
  ...

There was a semi-colon missing and it broke the compile.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin

* 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits)
  fs: scale mntget/mntput
  fs: rename vfsmount counter helpers
  fs: implement faster dentry memcmp
  fs: prefetch inode data in dcache lookup
  fs: improve scalability of pseudo filesystems
  fs: dcache per-inode inode alias locking
  fs: dcache per-bucket dcache hash locking
  bit_spinlock: add required includes
  kernel: add bl_list
  xfs: provide simple rcu-walk ACL implementation
  btrfs: provide simple rcu-walk ACL implementation
  ext2,3,4: provide simple rcu-walk ACL implementation
  fs: provide simple rcu-walk generic_check_acl implementation
  fs: provide rcu-walk aware permission i_ops
  fs: rcu-walk aware d_revalidate method
  fs: cache optimise dentry and inode for rcu-walk
  fs: dcache reduce branches in lookup path
  fs: dcache remove d_mounted
  fs: fs_struct use seqlock
  fs: rcu-walk for path lookup
  ...

The problem that this patch aims to fix is vfsmount refcounting scalability.
We need to take a reference on the vfsmount for every successful path lookup,
which often go to the same mount point.

The fundamental difficulty is that a "simple" reference count can never be made
scalable, because any time a reference is dropped, we must check whether that
was the last reference. To do that requires communication with all other CPUs
that may have taken a reference count.

We can make refcounts more scalable in a couple of ways, involving keeping
distributed counters, and checking for the global-zero condition less
frequently.

- check the global sum once every interval (this will delay zero detection
  for some interval, so it's probably a showstopper for vfsmounts).

- keep a local count and only taking the global sum when local reaches 0 (this
  is difficult for vfsmounts, because we can't hold preempt off for the life of
  a reference, so a counter would need to be per-thread or tied strongly to a
  particular CPU which requires more locking).

- keep a local difference of increments and decrements, which allows us to sum
  the total difference and hence find the refcount when summing all CPUs. Then,
  keep a single integer "long" refcount for slow and long lasting references,
  and only take the global sum of local counters when the long refcount is 0.

This last scheme is what I implemented here. Attached mounts and process root
and working directory references are "long" references, and everything else is
a short reference.

This allows scalable vfsmount references during path walking over mounted
subtrees and unattached (lazy umounted) mounts with processes still running
in them.

This results in one fewer atomic op in the fastpath: mntget is now just a
per-CPU inc, rather than an atomic inc; and mntput just requires a spinlock
and non-atomic decrement in the common case. However code is otherwise bigger
and heavier, so single threaded performance is basically a wash.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

Suggested by Andreas, mnt_ prefix is clearer namespace, follows kernel
conventions better, and is easier for tab complete. I introduced these
names so I'll admit they were not good choices.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

The standard memcmp function on a Westmere system shows up hot in
profiles in the `git diff` workload (both parallel and single threaded),
and it is likely due to the costs associated with trapping into
microcode, and little opportunity to improve memory access (dentry
name is not likely to take up more than a cacheline).

So replace it with an open-coded byte comparison. This increases code
size by 8 bytes in the critical __d_lookup_rcu function, but the
speedup is huge, averaging 10 runs of each:

git diff st   user   sys   elapsed  CPU
before        1.15   2.57  3.82      97.1
after         1.14   2.35  3.61      96.8

git diff mt   user   sys   elapsed  CPU
before        1.27   3.85  1.46     349
after         1.26   3.54  1.43     333

Elapsed time for single threaded git diff at 95.0% confidence:
        -0.21  +/- 0.01
        -5.45% +/- 0.24%

It's -0.66% +/- 0.06% elapsed time on my Opteron, so rep cmp costs on the
fam10h seem to be relatively smaller, but there is still a win.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

This makes single threaded git diff -1.25% +/- 0.05% elapsed time on my
2s12c24t Westmere system, and -0.86% +/- 0.05% on my 2s8c Barcelona, by
prefetching the important first cacheline of the inode in while we do the
actual name compare and other operations on the dentry.

There was no measurable slowdown in the single file stat case, or the creat
case (where negative dentries would be common).
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

Regardless of how much we possibly try to scale dcache, there is likely
always going to be some fundamental contention when adding or removing children
under the same parent. Pseudo filesystems do not seem need to have connected
dentries because by definition they are disconnected.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

dcache_inode_lock can be replaced with per-inode locking. Use existing
inode->i_lock for this. This is slightly non-trivial because we sometimes
need to find the inode from the dentry, which requires d_inode to be
stabilised (either with refcount or d_lock).
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

We can turn the dcache hash locking from a global dcache_hash_lock into
per-bucket locking.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

Introduce a type of hlist that can support the use of the lowest bit in the
hlist_head. This will be subsequently used to implement per-bucket bit spinlock
for inode and dentry hashes, and may be useful in other cases such as network
hashes.
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.

This could easily be extended to put acls under RCU and check them
under seqlock, if need be. But this implementation is enough to show
the rcu-walk aware permissions code for path lookups is working, and
will handle cases where there are no ACLs or ACLs in just the final
element.

This patch implicity converts tmpfs to rcu-aware permission check.
Subsequent patches onvert ext*, xfs, and, btrfs. Each of these uses
acl/permission code in a different way, so convert them all to provide
templates and proof of concept.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>

Signed-off-by: Nick Piggin <npiggin@kernel.dk>