linux-toradex.git/include, branch v3.17-rc5 Linux kernel for Apalis and Colibri modules vfs: avoid non-forwarding large load after small store in path lookup 2014-09-15T00:28:32+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-09-15T00:28:32+00:00 9226b5b440f2b4fbb3b797f3cb74a9a627220660 The performance regression that Josef Bacik reported in the pathname lookup (see commit 99d263d4c5b2 "vfs: fix bad hashing of dentries") made me look at performance stability of the dcache code, just to verify that the problem was actually fixed. That turned up a few other problems in this area. There are a few cases where we exit RCU lookup mode and go to the slow serializing case when we shouldn't, Al has fixed those and they'll come in with the next VFS pull. But my performance verification also shows that link_path_walk() turns out to have a very unfortunate 32-bit store of the length and hash of the name we look up, followed by a 64-bit read of the combined hash_len field. That screws up the processor store to load forwarding, causing an unnecessary hickup in this critical routine. It's caused by the ugly calling convention for the "hash_name()" function, and easily fixed by just making hash_name() fill in the whole 'struct qstr' rather than passing it a pointer to just the hash value. With that, the profile for this function looks much smoother. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The performance regression that Josef Bacik reported in the pathname
lookup (see commit 99d263d4c5b2 "vfs: fix bad hashing of dentries") made
me look at performance stability of the dcache code, just to verify that
the problem was actually fixed.  That turned up a few other problems in
this area.

There are a few cases where we exit RCU lookup mode and go to the slow
serializing case when we shouldn't, Al has fixed those and they'll come
in with the next VFS pull.

But my performance verification also shows that link_path_walk() turns
out to have a very unfortunate 32-bit store of the length and hash of
the name we look up, followed by a 64-bit read of the combined hash_len
field.  That screws up the processor store to load forwarding, causing
an unnecessary hickup in this critical routine.

It's caused by the ugly calling convention for the "hash_name()"
function, and easily fixed by just making hash_name() fill in the whole
'struct qstr' rather than passing it a pointer to just the hash value.

With that, the profile for this function looks much smoother.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branches 'locking-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-09-13T21:22:12+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-09-13T21:22:12+00:00 1536340e7c67694b134cbbc07168e5a524e49d08 Pull futex and timer fixes from Thomas Gleixner: "A oneliner bugfix for the jinxed futex code: - Drop hash bucket lock in the error exit path. I really could slap myself for intruducing that bug while fixing all the other horror in that code three month ago ... and the timer department is not too proud about the following fixes: - Deal with a long standing rounding bug in the timeval to jiffies conversion. It's a real issue and this fix fell through the cracks for quite some time. - Another round of alarmtimer fixes. Finally this code gets used more widely and the subtle issues hidden for quite some time are noticed and fixed. Nothing really exciting, just the itty bitty details which bite the serious users here and there" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Unlock hb->lock in futex_wait_requeue_pi() error path * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: alarmtimer: Lock k_itimer during timer callback alarmtimer: Do not signal SIGEV_NONE timers alarmtimer: Return relative times in timer_gettime jiffies: Fix timeval conversion to jiffies 
Pull futex and timer fixes from Thomas Gleixner:
 "A oneliner bugfix for the jinxed futex code:

   - Drop hash bucket lock in the error exit path.  I really could slap
     myself for intruducing that bug while fixing all the other horror
     in that code three month ago ...

  and the timer department is not too proud about the following fixes:

   - Deal with a long standing rounding bug in the timeval to jiffies
     conversion.  It's a real issue and this fix fell through the cracks
     for quite some time.

   - Another round of alarmtimer fixes.  Finally this code gets used
     more widely and the subtle issues hidden for quite some time are
     noticed and fixed.  Nothing really exciting, just the itty bitty
     details which bite the serious users here and there"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Unlock hb->lock in futex_wait_requeue_pi() error path

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  alarmtimer: Lock k_itimer during timer callback
  alarmtimer: Do not signal SIGEV_NONE timers
  alarmtimer: Return relative times in timer_gettime
  jiffies: Fix timeval conversion to jiffies
Make hash_64() use a 64-bit multiply when appropriate 2014-09-13T18:24:03+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-09-13T18:24:03+00:00 23d0db76ffa13ffb95229946e4648568c3c29db5 The hash_64() function historically does the multiply by the GOLDEN_RATIO_PRIME_64 number with explicit shifts and adds, because unlike the 32-bit case, gcc seems unable to turn the constant multiply into the more appropriate shift and adds when required. However, that means that we generate those shifts and adds even when the architecture has a fast multiplier, and could just do it better in hardware. Use the now-cleaned-up CONFIG_ARCH_HAS_FAST_MULTIPLIER (together with "is it a 64-bit architecture") to decide whether to use an integer multiply or the explicit sequence of shift/add instructions. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The hash_64() function historically does the multiply by the
GOLDEN_RATIO_PRIME_64 number with explicit shifts and adds, because
unlike the 32-bit case, gcc seems unable to turn the constant multiply
into the more appropriate shift and adds when required.

However, that means that we generate those shifts and adds even when the
architecture has a fast multiplier, and could just do it better in
hardware.

Use the now-cleaned-up CONFIG_ARCH_HAS_FAST_MULTIPLIER (together with
"is it a 64-bit architecture") to decide whether to use an integer
multiply or the explicit sequence of shift/add instructions.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge tag 'stable/for-linus-3.17-b-rc4-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip 2014-09-13T00:45:27+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-09-13T00:45:27+00:00 fc486b03cae382601b366ab460b05e1a01bf69cd Pull Xen ARM bugfix from Stefano Stabellini: "The patches fix the "xen_add_mach_to_phys_entry: cannot add" bug that has been affecting xen on arm and arm64 guests since 3.16. They require a few hypervisor side changes that just went in xen-unstable. A couple of days ago David sent out a pull request with a few other Xen fixes (it is already in master). Sorry we didn't synchronized better among us" * tag 'stable/for-linus-3.17-b-rc4-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/arm: remove mach_to_phys rbtree xen/arm: reimplement xen_dma_unmap_page & friends xen/arm: introduce XENFEAT_grant_map_identity 
Pull Xen ARM bugfix from Stefano Stabellini:
 "The patches fix the "xen_add_mach_to_phys_entry: cannot add" bug that
  has been affecting xen on arm and arm64 guests since 3.16.  They
  require a few hypervisor side changes that just went in xen-unstable.

  A couple of days ago David sent out a pull request with a few other
  Xen fixes (it is already in master).  Sorry we didn't synchronized
  better among us"

* tag 'stable/for-linus-3.17-b-rc4-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/arm: remove mach_to_phys rbtree
  xen/arm: reimplement xen_dma_unmap_page & friends
  xen/arm: introduce XENFEAT_grant_map_identity
jiffies: Fix timeval conversion to jiffies 2014-09-12T20:59:03+00:00 Andrew Hunter ahh@google.com 2014-09-04T21:17:16+00:00 d78c9300c51d6ceed9f6d078d4e9366f259de28c timeval_to_jiffies tried to round a timeval up to an integral number of jiffies, but the logic for doing so was incorrect: intervals corresponding to exactly N jiffies would become N+1. This manifested itself particularly repeatedly stopping/starting an itimer: setitimer(ITIMER_PROF, &val, NULL); setitimer(ITIMER_PROF, NULL, &val); would add a full tick to val, _even if it was exactly representable in terms of jiffies_ (say, the result of a previous rounding.) Doing this repeatedly would cause unbounded growth in val. So fix the math. Here's what was wrong with the conversion: we essentially computed (eliding seconds) jiffies = usec * (NSEC_PER_USEC/TICK_NSEC) by using scaling arithmetic, which took the best approximation of NSEC_PER_USEC/TICK_NSEC with denominator of 2^USEC_JIFFIE_SC = x/(2^USEC_JIFFIE_SC), and computed: jiffies = (usec * x) >> USEC_JIFFIE_SC and rounded this calculation up in the intermediate form (since we can't necessarily exactly represent TICK_NSEC in usec.) But the scaling arithmetic is a (very slight) *over*approximation of the true value; that is, instead of dividing by (1 usec/ 1 jiffie), we effectively divided by (1 usec/1 jiffie)-epsilon (rounding down). This would normally be fine, but we want to round timeouts up, and we did so by adding 2^USEC_JIFFIE_SC - 1 before the shift; this would be fine if our division was exact, but dividing this by the slightly smaller factor was equivalent to adding just _over_ 1 to the final result (instead of just _under_ 1, as desired.) In particular, with HZ=1000, we consistently computed that 10000 usec was 11 jiffies; the same was true for any exact multiple of TICK_NSEC. We could possibly still round in the intermediate form, adding something less than 2^USEC_JIFFIE_SC - 1, but easier still is to convert usec->nsec, round in nanoseconds, and then convert using time*spec*_to_jiffies. This adds one constant multiplication, and is not observably slower in microbenchmarks on recent x86 hardware. Tested: the following program: int main() { struct itimerval zero = {{0, 0}, {0, 0}}; /* Initially set to 10 ms. */ struct itimerval initial = zero; initial.it_interval.tv_usec = 10000; setitimer(ITIMER_PROF, &initial, NULL); /* Save and restore several times. */ for (size_t i = 0; i < 10; ++i) { struct itimerval prev; setitimer(ITIMER_PROF, &zero, &prev); /* on old kernels, this goes up by TICK_USEC every iteration */ printf("previous value: %ld %ld %ld %ld\n", prev.it_interval.tv_sec, prev.it_interval.tv_usec, prev.it_value.tv_sec, prev.it_value.tv_usec); setitimer(ITIMER_PROF, &prev, NULL); } return 0; } Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul Turner <pjt@google.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Reviewed-by: Paul Turner <pjt@google.com> Reported-by: Aaron Jacobs <jacobsa@google.com> Signed-off-by: Andrew Hunter <ahh@google.com> [jstultz: Tweaked to apply to 3.17-rc] Signed-off-by: John Stultz <john.stultz@linaro.org> 
timeval_to_jiffies tried to round a timeval up to an integral number
of jiffies, but the logic for doing so was incorrect: intervals
corresponding to exactly N jiffies would become N+1. This manifested
itself particularly repeatedly stopping/starting an itimer:

setitimer(ITIMER_PROF, &val, NULL);
setitimer(ITIMER_PROF, NULL, &val);

would add a full tick to val, _even if it was exactly representable in
terms of jiffies_ (say, the result of a previous rounding.)  Doing
this repeatedly would cause unbounded growth in val.  So fix the math.

Here's what was wrong with the conversion: we essentially computed
(eliding seconds)

jiffies = usec  * (NSEC_PER_USEC/TICK_NSEC)

by using scaling arithmetic, which took the best approximation of
NSEC_PER_USEC/TICK_NSEC with denominator of 2^USEC_JIFFIE_SC =
x/(2^USEC_JIFFIE_SC), and computed:

jiffies = (usec * x) >> USEC_JIFFIE_SC

and rounded this calculation up in the intermediate form (since we
can't necessarily exactly represent TICK_NSEC in usec.) But the
scaling arithmetic is a (very slight) *over*approximation of the true
value; that is, instead of dividing by (1 usec/ 1 jiffie), we
effectively divided by (1 usec/1 jiffie)-epsilon (rounding
down). This would normally be fine, but we want to round timeouts up,
and we did so by adding 2^USEC_JIFFIE_SC - 1 before the shift; this
would be fine if our division was exact, but dividing this by the
slightly smaller factor was equivalent to adding just _over_ 1 to the
final result (instead of just _under_ 1, as desired.)

In particular, with HZ=1000, we consistently computed that 10000 usec
was 11 jiffies; the same was true for any exact multiple of
TICK_NSEC.

We could possibly still round in the intermediate form, adding
something less than 2^USEC_JIFFIE_SC - 1, but easier still is to
convert usec->nsec, round in nanoseconds, and then convert using
time*spec*_to_jiffies.  This adds one constant multiplication, and is
not observably slower in microbenchmarks on recent x86 hardware.

Tested: the following program:

int main() {
  struct itimerval zero = {{0, 0}, {0, 0}};
  /* Initially set to 10 ms. */
  struct itimerval initial = zero;
  initial.it_interval.tv_usec = 10000;
  setitimer(ITIMER_PROF, &initial, NULL);
  /* Save and restore several times. */
  for (size_t i = 0; i < 10; ++i) {
    struct itimerval prev;
    setitimer(ITIMER_PROF, &zero, &prev);
    /* on old kernels, this goes up by TICK_USEC every iteration */
    printf("previous value: %ld %ld %ld %ld\n",
           prev.it_interval.tv_sec, prev.it_interval.tv_usec,
           prev.it_value.tv_sec, prev.it_value.tv_usec);
    setitimer(ITIMER_PROF, &prev, NULL);
  }
    return 0;
}

Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: Paul Turner <pjt@google.com>
Reported-by: Aaron Jacobs <jacobsa@google.com>
Signed-off-by: Andrew Hunter <ahh@google.com>
[jstultz: Tweaked to apply to 3.17-rc]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Merge tag 'usb-3.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb 2014-09-12T18:59:10+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-09-12T18:59:10+00:00 90a3c48fbfbfc2451f1edc145acef8b9892ad1e6 Pull USB fixes from Greg KH: "Here are some USB and PHY fixes for 3.17-rc5. Nothing major here, just a number of tiny fixes for reported issues, and some new device ids as well. All have been tested in linux-next" * tag 'usb-3.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (46 commits) xhci: fix oops when xhci resumes from hibernate with hw lpm capable devices usb: xhci: Fix OOPS in xhci error handling code xhci: Fix null pointer dereference if xhci initialization fails storage: Add single-LUN quirk for Jaz USB Adapter uas: Add missing le16_to_cpu calls to asm1051 / asm1053 usb-id check usb: chipidea: msm: Initialize PHY on reset event usb: chipidea: msm: Use USB PHY API to control PHY state usb: hub: take hub->hdev reference when processing from eventlist uas: Disable uas on ASM1051 devices usb: dwc2/gadget: avoid disabling ep0 usb: dwc2/gadget: delay enabling irq once hardware is configured properly usb: dwc2/gadget: do not call disconnect method in pullup usb: dwc2/gadget: break infinite loop in endpoint disable code usb: dwc2/gadget: fix phy initialization sequence usb: dwc2/gadget: fix phy disable sequence uwb: init beacon cache entry before registering uwb device USB: ftdi_sio: Add support for GE Healthcare Nemo Tracker device USB: document the 'u' flag for usb-storage quirks parameter usb: host: xhci: fix compliance mode workaround usb: dwc3: fix TRB completion when multiple TRBs are started ... 
Pull USB fixes from Greg KH:
 "Here are some USB and PHY fixes for 3.17-rc5.

  Nothing major here, just a number of tiny fixes for reported issues,
  and some new device ids as well.

  All have been tested in linux-next"

* tag 'usb-3.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (46 commits)
  xhci: fix oops when xhci resumes from hibernate with hw lpm capable devices
  usb: xhci: Fix OOPS in xhci error handling code
  xhci: Fix null pointer dereference if xhci initialization fails
  storage: Add single-LUN quirk for Jaz USB Adapter
  uas: Add missing le16_to_cpu calls to asm1051 / asm1053 usb-id check
  usb: chipidea: msm: Initialize PHY on reset event
  usb: chipidea: msm: Use USB PHY API to control PHY state
  usb: hub: take hub->hdev reference when processing from eventlist
  uas: Disable uas on ASM1051 devices
  usb: dwc2/gadget: avoid disabling ep0
  usb: dwc2/gadget: delay enabling irq once hardware is configured properly
  usb: dwc2/gadget: do not call disconnect method in pullup
  usb: dwc2/gadget: break infinite loop in endpoint disable code
  usb: dwc2/gadget: fix phy initialization sequence
  usb: dwc2/gadget: fix phy disable sequence
  uwb: init beacon cache entry before registering uwb device
  USB: ftdi_sio: Add support for GE Healthcare Nemo Tracker device
  USB: document the 'u' flag for usb-storage quirks parameter
  usb: host: xhci: fix compliance mode workaround
  usb: dwc3: fix TRB completion when multiple TRBs are started
  ...
xen/arm: introduce XENFEAT_grant_map_identity 2014-09-11T18:11:52+00:00 Stefano Stabellini stefano.stabellini@eu.citrix.com 2014-09-10T22:49:30+00:00 5ebc77de83c7b74543de774afa7395b3b790e65e The flag tells us that the hypervisor maps a grant page to guest physical address == machine address of the page in addition to the normal grant mapping address. It is needed to properly issue cache maintenance operation at the completion of a DMA operation involving a foreign grant. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Tested-by: Denis Schneider <v1ne2go@gmail.com> 
The flag tells us that the hypervisor maps a grant page to guest
physical address == machine address of the page in addition to the
normal grant mapping address. It is needed to properly issue cache
maintenance operation at the completion of a DMA operation involving a
foreign grant.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Denis Schneider <v1ne2go@gmail.com>
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2014-09-11T17:08:36+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-09-11T17:08:36+00:00 c8c16e3624ec9e2b36b76b34266c5064ec7e5f98 Pull input updates from Dmitry Torokhov: "An update to Synaptics PS/2 driver to handle "ForcePads" (currently found in HP EliteBook 1040 laptops), a change for Elan PS/2 driver to detect newer touchpads, bunch of devices get annotated as Trackpoint and/or Pointer to help userspace classify and handle them, plus assorted driver fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: serport - add compat handling for SPIOCSTYPE ioctl Input: atmel_mxt_ts - fix double free of input device Input: synaptics - add support for ForcePads Input: matrix_keypad - use request_any_context_irq() Input: atmel_mxt_ts - downgrade warning about empty interrupts Input: wm971x - fix typo in module parameter description Input: cap1106 - fix register definition Input: add missing POINTER / DIRECT properties to a bunch of drivers Input: add INPUT_PROP_POINTING_STICK property Input: elantech - fix detection of touchpad on ASUS s301l 
Pull input updates from Dmitry Torokhov:
 "An update to Synaptics PS/2 driver to handle "ForcePads" (currently
  found in HP EliteBook 1040 laptops), a change for Elan PS/2 driver to
  detect newer touchpads, bunch of devices get annotated as Trackpoint
  and/or Pointer to help userspace classify and handle them, plus
  assorted driver fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: serport - add compat handling for SPIOCSTYPE ioctl
  Input: atmel_mxt_ts - fix double free of input device
  Input: synaptics - add support for ForcePads
  Input: matrix_keypad - use request_any_context_irq()
  Input: atmel_mxt_ts - downgrade warning about empty interrupts
  Input: wm971x - fix typo in module parameter description
  Input: cap1106 - fix register definition
  Input: add missing POINTER / DIRECT properties to a bunch of drivers
  Input: add INPUT_PROP_POINTING_STICK property
  Input: elantech - fix detection of touchpad on ASUS s301l
shm: add memfd.h to UAPI export list 2014-09-10T22:42:12+00:00 David Drysdale drysdale@google.com 2014-09-09T21:50:57+00:00 b01d072065b6f36550f486fe77f05b092225ba1b The new header file memfd.h from commit 9183df25fe7b ("shm: add memfd_create() syscall") should be exported. Signed-off-by: David Drysdale <drysdale@google.com> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The new header file memfd.h from commit 9183df25fe7b ("shm: add
memfd_create() syscall") should be exported.

Signed-off-by: David Drysdale <drysdale@google.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Input: add INPUT_PROP_POINTING_STICK property 2014-09-08T21:58:11+00:00 Hans de Goede hdegoede@redhat.com 2014-09-08T21:42:12+00:00 7611392fe8ff95ecae528b01a815ae3d72ca6b95 It is useful for userspace to know that there not dealing with a regular mouse but rather with a pointing stick (e.g. a trackpoint) so that userspace can e.g. automatically enable middle button scrollwheel emulation. It is impossible to tell the difference from the evdev info without resorting to putting a list of device / driver names in userspace, this is undesirable. Add a property which allows userspace to see if a device is a pointing stick, and set it on all the pointing stick drivers. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Acked-by: Peter Hutterer <peter.hutterer@who-t.net> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> 
It is useful for userspace to know that there not dealing with a regular
mouse but rather with a pointing stick (e.g. a trackpoint) so that
userspace can e.g. automatically enable middle button scrollwheel
emulation.

It is impossible to tell the difference from the evdev info without
resorting to putting a list of device / driver names in userspace, this is
undesirable.

Add a property which allows userspace to see if a device is a pointing
stick, and set it on all the pointing stick drivers.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>