Commit Graph

456574 Commits

Author SHA1 Message Date
Axel Lin
b591d3c196 hwmon: (adm1026) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:37 -07:00
Axel Lin
97df55661a hwmon: (adm1026) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:37 -07:00
Axel Lin
aab3f57a11 hwmon: (adm1025) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
851a7afa82 hwmon: (adm1025) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
48995bc4bb hwmon: (adm1021) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
d1b9c3f503 hwmon: (gl520sm) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
df51f2d7bc hwmon: (gl520sm) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
18faf5b9be hwmon: (gl518sm) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
d4a972a339 hwmon: (gl518sm) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
6579d589ea hwmon: (lm93) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Guenter Roeck
40ebdb9274 hwmon: (w83791d) Fix smatch warning
smatch complains as follows when checking w83791d.c.

drivers/hwmon/w83791d.c:996 store_temp23() warn:
	'32768' 32768 can't fit into 32767 'data->temp_add[nr][index]'

Fix by using DIV_ROUND_CLOSEST and clamp_val to convert the values.
While we are at it, modify other macros as well for consistency and
to make the code easier to understand.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Guenter Roeck
7560dc0a6d hwmon: (lm63) Fix smatch warnings
smatch complains as follows when checking lm63.c.

drivers/hwmon/lm63.c:594 set_temp11() warn:
		'65504' 65504 can't fit into 32767 'data->temp11[nr]'
drivers/hwmon/lm63.c:596 set_temp11() warn:
		'32768' 32768 can't fit into 32767 'data->temp11[nr]'

Fix by using DIV_ROUND_CLOSEST and clamp_val to convert the values.
While we are at it, modify other macros as well for consistency and
to make the code easier to understand.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:36 -07:00
Axel Lin
034b44b4a2 hwmon: Make regmap configs const
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
fa0efc4091 hwmon: (htu21) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
7b3dadc4b3 hwmon: (emc6w201) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
1276fae2a9 hwmon: (amc6821) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
28e6274d8f hwmon: (amc6821) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
4fd5233f82 hwmon: (adm1029) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
b12e484e8c hwmon: (adm1029) Avoid forward declarations
Reorder functions to avoid forward declarations.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
337076f9b6 hwmon: (ad7418) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
991763a91c hwmon: (ad7418) Avoid forward declaration
Move ad7418_driver to proper place to avoid forward declaration.
Also move ad7418_init_client() close to ad7418_probe().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Axel Lin
045c1391ec hwmon: (ad7414) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Johannes Pointner
ed67f0872b hwmon: (ntc_thermistor) Support B57330V2103 from EPCOS
This patch adds support for the ntc thermistor B57330V2103 from EPCOS.

Signed-off-by: Johannes Pointner <johannes.pointner@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:35 -07:00
Johannes Pointner
3ef0bb6f76 devicetree: Add vendor prefix "epcos" to vendor-prefixes.txt
This patch adds the vendor prefix for "epcos" to the vendor-prefixes.

Signed-off-by: Johannes Pointner <johannes.pointner@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
a5afc18c9f hwmon: (hih6130) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Tested-by: Iain Paton <ipaton0@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
233adcefee hwmon: (tmp103) Add missing i2c_set_clientdata call in tmp103_probe
Add missing i2c_set_clientdata() call in tmp103_probe, this makes the
dev_get_drvdata() call in tmp103_suspend/tmp103_resume return correct
address.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Frans Klaver
c83959f89f hwmon: (lm75) Add support for TMP112
TMP112 is compatible to LM75.

Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
202e4851f8 hwmon: (w83l786ng) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Kevin Lo <kevlo@kevlo.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
bab711ae8c hwmon: (w83l786ng) Avoid forward declaration
Reorder functions to avoid forward declaration.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Kevin Lo <kevlo@kevlo.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
562dc9732a hwmon: (fam15h_power) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
b3aabd6db3 hwmon: (wm8350) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
9a70c97b21 hwmon: (wm831x) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
f82b2c3449 hwmon: (ads7828) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:34 -07:00
Axel Lin
11f7e494fd hwmon: (atxp1) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups.
This simplifies the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:33 -07:00
Heiko Schocher
d17a7dca04 hwmon: Driver for TI TMP103 temperature sensor
Driver for the TI TMP103.

The TI TMP103 is similar to the TMP102.  It differs from the TMP102
by having only 8 bit registers.

Signed-off-by: Heiko Schocher <hs@denx.de>
[linux@roeck-us.net: Select REGMAP_I2C in Kconfig]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:33 -07:00
Axel Lin
49153b092c hwmon: (gpio-fan) Convert to devm_hwmon_device_register_with_groups
This simplifies the code a bit and also ensures the attribute groups are
properly removed from sysfs when unload the module.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:33 -07:00
Axel Lin
5495af5f3e hwmon: (twl4030-madc-hwmon) Convert to devm_hwmon_device_register_with_groups
Use ATTRIBUTE_GROUPS macro and devm_hwmon_device_register_with_groups() to
simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:33 -07:00
Scott Kanowitz
f4ff415564 hwmon: Add support for Lattice's POWR1220 power manager IC
This patch adds support for Lattice's POWR1220 power manager IC. Read
access to all the ADCs on the chip are supported through the hwmon
sysfs files.

Signed-off-by: Scott Kanowitz <skanowitz@echo360.com>
[Guenter Roeck: Removed some extra ( )]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-08-04 07:01:33 -07:00
Axel Lin
99765db299 hwmon: (lm77) Prevent overflow problem when writing large limits
On platforms with sizeof(int) < sizeof(long), writing a temperature
limit larger than MAXINT will result in unpredictable limit values
written to the chip.
Clamp the input values to the supported limits first to fix the problem.

For set_temp_hyst:
As Guenter pointed out that the temperature is read as unsigned and stored in
an unsigned long. This is wrong; nothing in the datasheet suggests that the
value (the absolute temperature) must be positive.
So change it to signed.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-07-31 09:41:46 -07:00
Axel Lin
cf44819c98 hwmon: (amc6821) Fix possible race condition bug
Ensure mutex lock protects the read-modify-write period to prevent possible
race condition bug.
In additional, update data->valid should also be protected by the mutex lock.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-07-30 21:42:37 -07:00
Guenter Roeck
1074d683a5 hwmon: (lm78) Fix overflow problems seen when writing large temperature limits
On platforms with sizeof(int) < sizeof(long), writing a temperature
limit larger than MAXINT will result in unpredictable limit values
written to the chip. Avoid auto-conversion from long to int to fix
the problem.

Cc: Axel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-07-30 21:42:37 -07:00
Guenter Roeck
3248c3b771 hwmon: (lm85) Fix various errors on attribute writes
Temperature limit register writes did not account for negative numbers.
As a result, writing -127000 resulted in -126000 written into the
temperature limit register. This problem affected temp[1-3]_min,
temp[1-3]_max, temp[1-3]_auto_temp_crit, and temp[1-3]_auto_temp_min.

When writing pwm[1-3]_freq, a long variable was auto-converted into an int
without range check. Wiring values larger than MAXINT resulted in unexpected
register values.

When writing temp[1-3]_auto_temp_max, an unsigned long variable was
auto-converted into an int without range check. Writing values larger than
MAXINT resulted in unexpected register values.

vrm is an u8, so the written value needs to be limited to [0, 255].

Cc: Axel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-07-30 21:42:33 -07:00
Axel Lin
56de1377ad hwmon: (ads1015) Fix off-by-one for valid channel index checking
Current code uses channel as array index, so the valid channel value is
0 .. ADS1015_CHANNELS - 1.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-07-29 20:27:10 -07:00
Linus Torvalds
64aa90f26c Linux 3.16-rc7 2014-07-27 12:41:55 -07:00
Linus Torvalds
9dae0a3fc4 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
 "A bunch of fixes for perf and kprobes:
   - revert a commit that caused a perf group regression
   - silence dmesg spam
   - fix kprobe probing errors on ia64 and ppc64
   - filter kprobe faults from userspace
   - lockdep fix for perf exit path
   - prevent perf #GP in KVM guest
   - correct perf event and filters"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Fix "Failed to find blacklist" probing errors on ia64 and ppc64
  kprobes/x86: Don't try to resolve kprobe faults from userspace
  perf/x86/intel: Avoid spamming kernel log for BTS buffer failure
  perf/x86/intel: Protect LBR and extra_regs against KVM lying
  perf: Fix lockdep warning on process exit
  perf/x86/intel/uncore: Fix SNB-EP/IVT Cbox filter mappings
  perf/x86/intel: Use proper dTLB-load-misses event on IvyBridge
  perf: Revert ("perf: Always destroy groups on exit")
2014-07-27 09:57:16 -07:00
Linus Torvalds
43a255c210 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Peter Anvin:
 "A couple of crash fixes, plus a fix that on 32 bits would cause a
  missing -ENOSYS for nonexistent system calls"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, cpu: Fix cache topology for early P4-SMT
  x86_32, entry: Store badsys error code in %eax
  x86, MCE: Robustify mcheck_init_device
2014-07-27 09:53:01 -07:00
Linus Torvalds
fbf08efa04 Merge branch 'vfs-for-3.16' of git://git.infradead.org/users/hch/vfs
Pull vfs fixes from Christoph Hellwig:
 "A vfsmount leak fix, and a compile warning fix"

* 'vfs-for-3.16' of git://git.infradead.org/users/hch/vfs:
  fs: umount on symlink leaks mnt count
  direct-io: fix uninitialized warning in do_direct_IO()
2014-07-27 09:43:41 -07:00
Linus Torvalds
2bdb5eb79b IEEE 1394 (FireWire) subsystem fix: MSI don't work on VIA PCIe controllers
with some isochronous workloads (regression since v3.16-rc1).
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Merge tag 'firewire-fix-vt6315' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394

Pull firewire regression fix from Stefan Richter:
 "IEEE 1394 (FireWire) subsystem fix: MSI don't work on VIA PCIe
  controllers with some isochronous workloads (regression since
  v3.16-rc1)"

* tag 'firewire-fix-vt6315' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: ohci: disable MSI for VIA VT6315 again
2014-07-27 09:42:06 -07:00
Linus Torvalds
2062afb4f8 Fix gcc-4.9.0 miscompilation of load_balance() in scheduler
Michel Dänzer and a couple of other people reported inexplicable random
oopses in the scheduler, and the cause turns out to be gcc mis-compiling
the load_balance() function when debugging is enabled.  The gcc bug
apparently goes back to gcc-4.5, but slight optimization changes means
that it now showed up as a problem in 4.9.0 and 4.9.1.

The instruction scheduling problem causes gcc to schedule a spill
operation to before the stack frame has been created, which in turn can
corrupt the spilled value if an interrupt comes in.  There may be other
effects of this bug too, but that's the code generation problem seen in
Michel's case.

This is fixed in current gcc HEAD, but the workaround as suggested by
Markus Trippelsdorf is pretty simple: use -fno-var-tracking-assignments
when compiling the kernel, which disables the gcc code that causes the
problem.  This can result in slightly worse debug information for
variable accesses, but that is infinitely preferable to actual code
generation problems.

Doing this unconditionally (not just for CONFIG_DEBUG_INFO) also allows
non-debug builds to verify that the debug build would be identical: we
can do

    export GCC_COMPARE_DEBUG=1

to make gcc internally verify that the result of the build is
independent of the "-g" flag (it will make the compiler build everything
twice, toggling the debug flag, and compare the results).

Without the "-fno-var-tracking-assignments" option, the build would fail
(even with 4.8.3 that didn't show the actual stack frame bug) with a gcc
compare failure.

See also gcc bugzilla:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801

Reported-by: Michel Dänzer <michel@daenzer.net>
Suggested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-26 14:52:01 -07:00
Hugh Dickins
8bdd638091 mm: fix direct reclaim writeback regression
Shortly before 3.16-rc1, Dave Jones reported:

  WARNING: CPU: 3 PID: 19721 at fs/xfs/xfs_aops.c:971
           xfs_vm_writepage+0x5ce/0x630 [xfs]()
  CPU: 3 PID: 19721 Comm: trinity-c61 Not tainted 3.15.0+ #3
  Call Trace:
    xfs_vm_writepage+0x5ce/0x630 [xfs]
    shrink_page_list+0x8f9/0xb90
    shrink_inactive_list+0x253/0x510
    shrink_lruvec+0x563/0x6c0
    shrink_zone+0x3b/0x100
    shrink_zones+0x1f1/0x3c0
    try_to_free_pages+0x164/0x380
    __alloc_pages_nodemask+0x822/0xc90
    alloc_pages_vma+0xaf/0x1c0
    handle_mm_fault+0xa31/0xc50
  etc.

 970   if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
 971                   PF_MEMALLOC))

I did not respond at the time, because a glance at the PageDirty block
in shrink_page_list() quickly shows that this is impossible: we don't do
writeback on file pages (other than tmpfs) from direct reclaim nowadays.
Dave was hallucinating, but it would have been disrespectful to say so.

However, my own /var/log/messages now shows similar complaints

  WARNING: CPU: 1 PID: 28814 at fs/ext4/inode.c:1881 ext4_writepage+0xa7/0x38b()
  WARNING: CPU: 0 PID: 27347 at fs/ext4/inode.c:1764 ext4_writepage+0xa7/0x38b()

from stressing some mmotm trees during July.

Could a dirty xfs or ext4 file page somehow get marked PageSwapBacked,
so fail shrink_page_list()'s page_is_file_cache() test, and so proceed
to mapping->a_ops->writepage()?

Yes, 3.16-rc1's commit 68711a7463 ("mm, migration: add destination
page freeing callback") has provided such a way to compaction: if
migrating a SwapBacked page fails, its newpage may be put back on the
list for later use with PageSwapBacked still set, and nothing will clear
it.

Whether that can do anything worse than issue WARN_ON_ONCEs, and get
some statistics wrong, is unclear: easier to fix than to think through
the consequences.

Fixing it here, before the put_new_page(), addresses the bug directly,
but is probably the worst place to fix it.  Page migration is doing too
many parts of the job on too many levels: fixing it in
move_to_new_page() to complement its SetPageSwapBacked would be
preferable, except why is it (and newpage->mapping and newpage->index)
done there, rather than down in migrate_page_move_mapping(), once we are
sure of success? Not a cleanup to get into right now, especially not
with memcg cleanups coming in 3.17.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-26 14:38:50 -07:00