This driver can be used on Xilinx ARM Zynq platform
where in_be32/out_be32 functions are not implemented.
Use __raw_readl/__raw_writel functions which are
implemented on Microblaze and PowerPC.
For ARM readl/writel functions are used instead.

The correct way how to implement this is to detect
endians directly on IP. But for the gpio case
without interrupt connected(it means without
interrupt logic) there are just 2 registers
data and tristate where auto detection can't be done.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Supporting the second channel in the driver.
Offset is 0x8 and both channnels share the same
IRQ.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Simplification is done by using OF helper function
which increase readability of code and remove
(if (var) var = be32_to_cpup;) assignment.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Use devm_* functions to make cleanup paths simpler.
Signed-off-by: Nikolay Balandin <nbalandin@dev.rtsoft.ru>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Fix to return a negative error code in the irq descs alloc error
handling case instead of 0, as done elsewhere in this function.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Since the type of the reg_base member is void __iomem * we don't need to have
explicit casting in gpio_reg() and gpio_reg_2bit().

Update year in the copyright notice as well.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

There is no need to use hardcoded device name in the error messages, because
dev_err() prefixes the message with the device name anyway.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

This makes the error handling much more simpler than open-coding everything and
in addition makes the probe function smaller an tidier.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@intel.com>
[Rebased on the platform-data set to NULL removal patch]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

We better to use readl() function instead of bad looking direct access.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Otherwise we will end up with traceback from LOCKDEP:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.10.0-rc2-next-20130521-00028-g09aa9fc #487
 00000000 00000000 f6c55c54 c1541fe4 f6040bf8 f6c55c8c c1069ef1 c1726bc1
 c1726cc8 c1726c9e 00000000 f6c584e0 f6c58000 f6c55ce8 00000000 f6040bf8
 f6040bf8 00000046 f6c58000 f6c55d00 c106a18d 00000a2b 00000003 00004f02
Call Trace:
 [<c1541fe4>] dump_stack+0x49/0x77
 [<c1069ef1>] register_lock_class+0x58/0x260
 [<c106a18d>] __lock_acquire+0x94/0xcff
 [<c106adc8>] ? __lock_acquire+0xccf/0xcff
 [<c106b2ad>] lock_acquire+0xcc/0x10d
 [<c1269c7c>] ? lnw_irq_type+0x63/0xe9
 [<c1545da0>] _raw_spin_lock_irqsave+0x32/0x42
 [<c1269c7c>] ? lnw_irq_type+0x63/0xe9
 [<c1269c7c>] lnw_irq_type+0x63/0xe9
 [<c108f454>] __irq_set_trigger+0x98/0x123
 [<c1090225>] irq_set_irq_type+0x2f/0x51
 [<c1090225>] ? irq_set_irq_type+0x2f/0x51
 [<c1269d02>] ? lnw_irq_type+0xe9/0xe9
 [<c1269d34>] lnw_gpio_irq_map+0x32/0x3b
 [<c10914f2>] irq_domain_add_legacy+0xe2/0x107
 [<c1091b53>] irq_domain_add_simple+0x47/0x60
 [<c1269f6e>] lnw_gpio_probe+0x119/0x217
 [<c1271018>] pci_device_probe+0x5a/0x92
...
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

max7301 is controlled through SPI interface which means another driver.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Both stmpe_gpio_irq_map() and stmpe_gpio_irq_unmap() are not referenced
outside of this file, make them static.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

do_smart_update_queue() is called when an operation (semop,
semctl(SETVAL), semctl(SETALL), ...) modified the array.  It must check
which of the sleeping tasks can proceed.

do_smart_update_queue() missed a few wakeups:
 - if a sleeping complex op was completed, then all per-semaphore queues
   must be scanned - not only those that were modified by *sops
 - if a sleeping simple op proceeded, then the global queue must be
   scanned again

And:
 - the test for "|sops == NULL) before scanning the global queue is not
   required: If the global queue is empty, then it doesn't need to be
   scanned - regardless of the reason for calling do_smart_update_queue()

The patch is not optimized, i.e.  even completing a wait-for-zero
operation causes a rescan.  This is done to keep the patch as simple as
possible.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull NFS client bugfixes from Trond Myklebust:

 - Stable fix to prevent an rpc_task wakeup race
 - Fix a NFSv4.1 session drain deadlock
 - Fix a NFSv4/v4.1 mount regression when not running rpc.gssd
 - Ensure auth_gss pipe detection works in namespaces
 - Fix SETCLIENTID fallback if rpcsec_gss is not available

* tag 'nfs-for-3.10-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: Fix SETCLIENTID fallback if GSS is not available
  SUNRPC: Prevent an rpc_task wakeup race
  NFSv4.1 Fix a pNFS session draining deadlock
  SUNRPC: Convert auth_gss pipe detection to work in namespaces
  SUNRPC: Faster detection if gssd is actually running
  SUNRPC: Fix a bug in gss_create_upcall

Pull amd64 edac fix from Borislav Petkov:
 "A sysfs file permissions correction"

* tag 'edac_fixes_for_3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  amd64_edac: Fix bogus sysfs file permissions

Pull parisc fixes from Helge Deller:
 "This time we made the kernel- and interruption stack allocation
  reentrant which fixed some strange kernel crashes (specifically
  protection ID traps).

  Furthemore this patchset fixes the interrupt stack in UP and SMP
  configurations by using native locking instructions.  And finally
  usage of floating point calculations on parisc were disabled in the
  MPILIB."

* 'parisc-for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: fix irq stack on UP and SMP
  parisc/superio: Use module_pci_driver to register driver
  parisc: make interrupt and interruption stack allocation reentrant
  parisc: show number of FPE and unaligned access handler calls in /proc/interrupts
  parisc: add additional parisc git tree to MAINTAINERS file
  parisc: use PAGE_SHIFT instead of hardcoded value 12 in pacache.S
  parisc: add rp5470 entry to machine database
  MPILIB: disable usage of floating point registers on parisc

Pull xfs fixes from Ben Myers:
 "Here are fixes for corruption on 512 byte filesystems, a rounding
  error, a use-after-free, some flags to fix lockdep reports, and
  several fixes related to CRCs.  We have a somewhat larger post -rc1
  queue than usual due to fixes related to the CRC feature we merged for
  3.10:

   - Fix for corruption with FSX on 512 byte blocksize filesystems
   - Fix rounding error in xfs_free_file_space
   - Fix use-after-free with extent free intents
   - Add several missing KM_NOFS flags to fix lockdep reports
   - Several fixes for CRC related code"

* tag 'for-linus-v3.10-rc3' of git://oss.sgi.com/xfs/xfs:
  xfs: remote attribute lookups require the value length
  xfs: xfs_attr_shortform_allfit() does not handle attr3 format.
  xfs: xfs_da3_node_read_verify() doesn't handle XFS_ATTR3_LEAF_MAGIC
  xfs: fix missing KM_NOFS tags to keep lockdep happy
  xfs: Don't reference the EFI after it is freed
  xfs: fix rounding in xfs_free_file_space
  xfs: fix sub-page blocksize data integrity writes

Pull bettery fixes from Anton Vorontsov:
 "Last minute one-liners: wrong kfree usage fix, module alias fixup and
  kconfig adjustments"

* tag 'for-v3.10-fixes' of git://git.infradead.org/battery-2.6:
  pm2301_charger: Fix module alias prefix
  wm831x_backup: Fix wrong kfree call for devdata->backup.name
  bq27x00: Fix I2C dependency in KConfig
  lp8788-charger: Fix kconfig dependency

Pull power management and ACPI fixes from Rafael Wysocki:

 - Additional CPU ID for the intel_pstate driver from Dirk Brandewie.

 - More cpufreq fixes related to ARM big.LITTLE support and locking from
   Viresh Kumar.

 - VIA C7 cpufreq build fix from Rafał Bilski.

 - ACPI power management fix making it possible to use device power
   states regardless of the CONFIG_PM setting from Rafael J Wysocki.

 - New ACPI video blacklist item from Bastian Triller.

* tag 'pm+acpi-3.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: Add "Asus UL30A" to ACPI video detect blacklist
  cpufreq: arm_big_little_dt: Instantiate as platform_driver
  cpufreq: arm_big_little_dt: Register driver only if DT has valid data
  cpufreq / e_powersaver: Fix linker error when ACPI processor is a module
  cpufreq / intel_pstate: Add additional supported CPU ID
  cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT
  ACPI / PM: Allow device power states to be used for CONFIG_PM unset

Pull slave-dma fixes from Vinod Koul:
 "We have two patches from Andy & Rafael fixing the Lynxpoint dma"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  ACPI / LPSS: register clock device for Lynxpoint DMA properly
  dma: acpi-dma: parse CSRT to extract additional resources

kcore_vmalloc is in fs/proc/kcore.c and kcore_mem is unused across
the tree. Noticed while grepping the tree for some other kcore stuff.

(score looks pretty unmaintained to me.)
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull ARC fixes from Vineet Gupta:

 - Fallouts/wreckage of Cache Flush optimizations / aliasing dcache
   support

 - Fix for an interesting bug where piped input to grep was getting
   mysteriously clobbered

* tag 'arc-v3.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: lazy dcache flush broke gdb in non-aliasing configs
  ARC: Use enough bits for determining page's cache color
  ARC: Brown paper bag bug in macro for checking cache color
  ARC: copy_(to|from)_user() to honor usermode-access permissions
  ARC: [mm] Prevent stray dcache lines after__sync_icache_dcach()
  ARC: [TB10x] Remove redundant abilis,simple-pinctrl mechanism

Pull ARM fixes from Russell King:
 "Just three this time, all really quite small"

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7729/1: vfp: ensure VFP_arch is non-zero when VFP is not supported
  ARM: 7727/1: remove the .vm_mm value from gate_vma
  ARM: 7723/1: crypto: sha1-armv4-large.S: fix SP handling

gdbserver inserting a breakpoint ends up calling copy_user_page() for a
code page. The generic version of which (non-aliasing config) didn't set
the PG_arch_1 bit hence update_mmu_cache() didn't sync dcache/icache for
corresponding dynamic loader code page - causing garbade to be executed.

So now aliasing versions of copy_user_highpage()/clear_page() are made
default. There is no significant overhead since all of special alias
handling code is compiled out for non-aliasing build
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Merge fixes from Andrew Morton:
 "A bunch of fixes and one simple fbdev driver which missed the merge
  window because people will still talking about it (to no great
  effect)."

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (30 commits)
  aio: fix kioctx not being freed after cancellation at exit time
  mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas
  drivers/rtc/rtc-max8998.c: check for pdata presence before dereferencing
  ocfs2: goto out_unlock if ocfs2_get_clusters_nocache() failed in ocfs2_fiemap()
  random: fix accounting race condition with lockless irq entropy_count update
  drivers/char/random.c: fix priming of last_data
  mm/memory_hotplug.c: fix printk format warnings
  nilfs2: fix issue of nilfs_set_page_dirty() for page at EOF boundary
  drivers/block/brd.c: fix brd_lookup_page() race
  fbdev: FB_GOLDFISH should depend on HAS_DMA
  drivers/rtc/rtc-pl031.c: pass correct pointer to free_irq()
  auditfilter.c: fix kernel-doc warnings
  aio: fix io_getevents documentation
  revert "selftest: add simple test for soft-dirty bit"
  drivers/leds/leds-ot200.c: fix error caused by shifted mask
  mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer
  linux/kernel.h: fix kernel-doc warning
  mm compaction: fix of improper cache flush in migration code
  rapidio/tsi721: fix bug in MSI interrupt handling
  hfs: avoid crash in hfs_bnode_create
  ...

Pull ARM SoC fixes from Olof Johansson:
 "We didn't have any fixes sent up for -rc2, so this is a slightly
  larger batch.  A bit all over the place platform-wise; OMAP, at91,
  marvell, renesas, sunxi, ux500, etc.

  I tried to summarize highlights but there isn't a whole lot to point
  out.  Lots of little things fixed all over.  A couple of defconfig
  updates due to new/changing options."

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (44 commits)
  ARM: at91/sama5: fix incorrect PMC pcr div definition
  ARM: at91/dt: fix macb pinctrl_macb_rmii_mii_alt definition
  ARM: at91: at91sam9n12: move external irq declatation to DT
  ARM: shmobile: marzen: Use error values in usb_power_*
  ARM: tegra: defconfig fixes
  ARM: nomadik: fix IRQ assignment for SMC ethernet
  ARM: vt8500: Add missing NULL terminator in dt_compat
  clk: tegra: add ac97 controller clock
  clk: tegra: remove USB from clk init table
  ARM: dts: mvebu: Fix wrong the address reg value for the L2-cache node
  ARM: plat-orion: Fix num_resources and id for ge10 and ge11
  ARM: OMAP2+: hwmod: Remove sysc slave idle and auto idle apis
  SERIAL: OMAP: Remove the slave idle handling from the driver
  ARM: OMAP2+: serial: Remove the un-used slave idle hooks
  ARM: OMAP2+: hwmod-data: UART IP needs software control to manage sidle modes
  ARM: OMAP2+: hwmod: Add a new flag to handle SIDLE in SWSUP only in active
  ARM: OMAP2+: hwmod: Fix sidle programming in _enable_sysc()/_idle_sysc()
  arm: mvebu: fix the 'ranges' property to handle PCIe
  ARM: mvebu: select ARCH_REQUIRE_GPIOLIB for mvebu platform
  ARM: AM33XX: Add missing .clkdm_name to clkdiv32k_ick clock
  ...

The recent changes overhauling fs/aio.c introduced a bug that results in
the kioctx not being freed when outstanding kiocbs are cancelled at
exit_aio() time.  Specifically, a kiocb that is cancelled has its
completion events discarded by batch_complete_aio(), which then fails to
wake up the process stuck in free_ioctx().  Fix this by modifying the
wait_event() condition in free_ioctx() appropriately.

This patch was tested with the cancel operation in the thread based code
posted yesterday.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Zach Brown <zab@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

A panic can be caused by simply cat'ing /proc/<pid>/smaps while an
application has a VM_PFNMAP range.  It happened in-house when a
benchmarker was trying to decipher the memory layout of his program.

/proc/<pid>/smaps and similar walks through a user page table should not
be looking at VM_PFNMAP areas.

Certain tests in walk_page_range() (specifically split_huge_page_pmd())
assume that all the mapped PFN's are backed with page structures.  And
this is not usually true for VM_PFNMAP areas.  This can result in panics
on kernel page faults when attempting to address those page structures.

There are a half dozen callers of walk_page_range() that walk through a
task's entire page table (as N.  Horiguchi pointed out).  So rather than
change all of them, this patch changes just walk_page_range() to ignore
VM_PFNMAP areas.

The logic of hugetlb_vma() is moved back into walk_page_range(), as we
want to test any vma in the range.

VM_PFNMAP areas are used by:
- graphics memory manager   gpu/drm/drm_gem.c
- global reference unit     sgi-gru/grufile.c
- sgi special memory        char/mspec.c
- and probably several out-of-tree modules

[akpm@linux-foundation.org: remove now-unused hugetlb_vma() stub]
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently the driver can crash with a NULL pointer dereference if no
pdata is provided, despite of successful registration of the MFD part.
This patch fixes the problem by adding a NULL check before dereferencing
the pdata pointer.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Last time we found there is lock/unlock bug in ocfs2_file_aio_write, and
then we did a thorough search for all lock resources in
ocfs2_inode_info, including rw, inode and open lockres and found this
bug.  My kernel version is 3.0.13, and it is also in the lastest version
3.9.  In ocfs2_fiemap, once ocfs2_get_clusters_nocache failed, it should
goto out_unlock instead of out, because we need release buffer head, up
read alloc sem and unlock inode.
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Acked-by: Sunil Mushran <sunil.mushran@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 902c098a ("random: use lockless techniques in the interrupt
path") turned IRQ path from being spinlock protected into lockless
cmpxchg-retry update.

That commit removed r->lock serialization between crediting entropy bits
from IRQ context and accounting when extracting entropy on userspace
read path, but didn't turn the r->entropy_count reads/updates in
account() to use cmpxchg as well.

It has been observed, that under certain circumstances this leads to
read() on /dev/urandom to return 0 (EOF), as r->entropy_count gets
corrupted and becomes negative, which in turn results in propagating 0
all the way from account() to the actual read() call.

Convert the accounting code to be the proper lockless counterpart of
what has been partially done by 902c098a.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Greg KH <greg@kroah.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>