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  1. 12 5月, 2013 1 次提交
    • R
      Driver core: Add offline/online device operations · 4f3549d7
      由 Rafael J. Wysocki 提交于 
      In some cases, graceful hot-removal of devices is not possible,
although in principle the devices in question support hotplug.
For example, that may happen for the last CPU in the system or
for memory modules holding kernel memory.

In those cases it is nice to be able to check if the given device
can be gracefully hot-removed before triggering a removal procedure
that cannot be aborted or reversed.  Unfortunately, however, the
kernel currently doesn't provide any support for that.

To address that deficiency, introduce support for offline and
online operations that can be performed on devices, respectively,
before a hot-removal and in case when it is necessary (or convenient)
to put a device back online after a successful offline (that has not
been followed by removal).  The idea is that the offline will fail
whenever the given device cannot be gracefully removed from the
system and it will not be allowed to use the device after a
successful offline (until a subsequent online) in analogy with the
existing CPU offline/online mechanism.

For now, the offline and online operations are introduced at the
bus type level, as that should be sufficient for the most urgent use
cases (CPUs and memory modules).  In the future, however, the
approach may be extended to cover some more complicated device
offline/online scenarios involving device drivers etc.

The lock_device_hotplug() and unlock_device_hotplug() functions are
introduced because subsequent patches need to put larger pieces of
code under device_hotplug_lock to prevent race conditions between
device offline and removal from happening.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NToshi Kani <toshi.kani@hp.com>
      4f3549d7
  3. 01 5月, 2013 2 次提交
  5. 30 4月, 2013 4 次提交
  7. 16 4月, 2013 1 次提交
    • S
      regmap: don't corrupt work buffer in _regmap_raw_write() · 5a08d156
      由 Stephen Warren 提交于 
      _regmap_raw_write() contains code to call regcache_write() to write
values to the cache. That code calls memcpy() to copy the value data to
the start of the work_buf. However, at least when _regmap_raw_write() is
called from _regmap_bus_raw_write(), the value data is in the work_buf,
and this memcpy() operation may over-write part of that value data,
depending on the value of reg_bytes + pad_bytes. At least when using
reg_bytes==1 and pad_bytes==0, corruption of the value data does occur.

To solve this, remove the memcpy() operation, and modify the subsequent
.parse_val() call to parse the original value buffer directly.

At least in the case of 8-bit register address and 16-bit values, and
writes of single registers at a time, this memcpy-then-parse combination
used to cancel each-other out; for a work-buffer containing xx 89 03,
the memcpy changed it to 89 03 03, and the parse_val changed it back to
89 89 03, thus leaving the value uncorrupted. This appears completely
accidental though. Since commit 8a819ff8 "regmap: core: Split out in
place value parsing", .parse_val only returns the parsed value, and does
not modify the buffer, and hence does not (accidentally) undo the
corruption caused by memcpy(). This caused bogus values to get written
to HW, thus preventing e.g. audio playback on systems with a WM8903
CODEC. This patch fixes that.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
      5a08d156
  9. 12 4月, 2013 5 次提交
  11. 11 4月, 2013 2 次提交
  13. 10 4月, 2013 1 次提交
    • M
      regmap: Back out work buffer fix · 51a246aa
      由 Mark Brown 提交于 
      This reverts commit bc8ce4 (regmap: don't corrupt work buffer in
_regmap_raw_write()) since it turns out that it can cause issues when
taken in isolation from the other changes in -next that lead to its
discovery.  On the basis that nobody noticed the problems for quite some
time without that subsequent work let's drop it from v3.9.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
      51a246aa
  15. 08 4月, 2013 1 次提交
    • K
      driver core: add uid and gid to devtmpfs · 3c2670e6
      由 Kay Sievers 提交于 
      Some drivers want to tell userspace what uid and gid should be used for
their device nodes, so allow that information to percolate through the
driver core to userspace in order to make this happen.  This means that
some systems (i.e.  Android and friends) will not need to even run a
udev-like daemon for their device node manager and can just rely in
devtmpfs fully, reducing their footprint even more.
Signed-off-by: NKay Sievers <kay@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3c2670e6
  17. 05 4月, 2013 3 次提交
  19. 04 4月, 2013 1 次提交
  21. 02 4月, 2013 1 次提交
    • R
      PM / QoS: Avoid possible deadlock related to sysfs access · 0f703069
      由 Rafael J. Wysocki 提交于 
      Commit b81ea1b5 (PM / QoS: Fix concurrency issues and memory leaks in
device PM QoS) put calls to pm_qos_sysfs_add_latency(),
pm_qos_sysfs_add_flags(), pm_qos_sysfs_remove_latency(), and
pm_qos_sysfs_remove_flags() under dev_pm_qos_mtx, which was a
mistake, because it may lead to deadlocks in some situations.
For example, if pm_qos_remote_wakeup_store() is run in parallel
with dev_pm_qos_constraints_destroy(), they may deadlock in the
following way:

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.9.0-rc4-next-20130328-sasha-00014-g91a3267 #319 Tainted: G        W
 -------------------------------------------------------
 trinity-child6/12371 is trying to acquire lock:
  (s_active#54){++++.+}, at: [<ffffffff81301631>] sysfs_addrm_finish+0x31/0x60

 but task is already holding lock:
  (dev_pm_qos_mtx){+.+.+.}, at: [<ffffffff81f07cc3>] dev_pm_qos_constraints_destroy+0x23/0x250

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (dev_pm_qos_mtx){+.+.+.}:
        [<ffffffff811811da>] lock_acquire+0x1aa/0x240
        [<ffffffff83dab809>] __mutex_lock_common+0x59/0x5e0
        [<ffffffff83dabebf>] mutex_lock_nested+0x3f/0x50
        [<ffffffff81f07f2f>] dev_pm_qos_update_flags+0x3f/0xc0
        [<ffffffff81f05f4f>] pm_qos_remote_wakeup_store+0x3f/0x70
        [<ffffffff81efbb43>] dev_attr_store+0x13/0x20
        [<ffffffff812ffdaa>] sysfs_write_file+0xfa/0x150
        [<ffffffff8127f2c1>] __kernel_write+0x81/0x150
        [<ffffffff812afc2d>] write_pipe_buf+0x4d/0x80
        [<ffffffff812af57c>] splice_from_pipe_feed+0x7c/0x120
        [<ffffffff812afa25>] __splice_from_pipe+0x45/0x80
        [<ffffffff812b14fc>] splice_from_pipe+0x4c/0x70
        [<ffffffff812b1538>] default_file_splice_write+0x18/0x30
        [<ffffffff812afae3>] do_splice_from+0x83/0xb0
        [<ffffffff812afb2e>] direct_splice_actor+0x1e/0x20
        [<ffffffff812b0277>] splice_direct_to_actor+0xe7/0x200
        [<ffffffff812b15bc>] do_splice_direct+0x4c/0x70
        [<ffffffff8127eda9>] do_sendfile+0x169/0x300
        [<ffffffff8127ff94>] SyS_sendfile64+0x64/0xb0
        [<ffffffff83db7d18>] tracesys+0xe1/0xe6

 -> #0 (s_active#54){++++.+}:
        [<ffffffff811800cf>] __lock_acquire+0x15bf/0x1e50
        [<ffffffff811811da>] lock_acquire+0x1aa/0x240
        [<ffffffff81300aa2>] sysfs_deactivate+0x122/0x1a0
        [<ffffffff81301631>] sysfs_addrm_finish+0x31/0x60
        [<ffffffff812ff77f>] sysfs_hash_and_remove+0x7f/0xb0
        [<ffffffff813035a1>] sysfs_unmerge_group+0x51/0x70
        [<ffffffff81f068f4>] pm_qos_sysfs_remove_flags+0x14/0x20
        [<ffffffff81f07490>] __dev_pm_qos_hide_flags+0x30/0x70
        [<ffffffff81f07cd5>] dev_pm_qos_constraints_destroy+0x35/0x250
        [<ffffffff81f06931>] dpm_sysfs_remove+0x11/0x50
        [<ffffffff81efcf6f>] device_del+0x3f/0x1b0
        [<ffffffff81efd128>] device_unregister+0x48/0x60
        [<ffffffff82d4083c>] usb_hub_remove_port_device+0x1c/0x20
        [<ffffffff82d2a9cd>] hub_disconnect+0xdd/0x160
        [<ffffffff82d36ab7>] usb_unbind_interface+0x67/0x170
        [<ffffffff81f001a7>] __device_release_driver+0x87/0xe0
        [<ffffffff81f00559>] device_release_driver+0x29/0x40
        [<ffffffff81effc58>] bus_remove_device+0x148/0x160
        [<ffffffff81efd07f>] device_del+0x14f/0x1b0
        [<ffffffff82d344f9>] usb_disable_device+0xf9/0x280
        [<ffffffff82d34ff8>] usb_set_configuration+0x268/0x840
        [<ffffffff82d3a7fc>] usb_remove_store+0x4c/0x80
        [<ffffffff81efbb43>] dev_attr_store+0x13/0x20
        [<ffffffff812ffdaa>] sysfs_write_file+0xfa/0x150
        [<ffffffff8127f71d>] do_loop_readv_writev+0x4d/0x90
        [<ffffffff8127f999>] do_readv_writev+0xf9/0x1e0
        [<ffffffff8127faba>] vfs_writev+0x3a/0x60
        [<ffffffff8127fc60>] SyS_writev+0x50/0xd0
        [<ffffffff83db7d18>] tracesys+0xe1/0xe6

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(dev_pm_qos_mtx);
                                lock(s_active#54);
                                lock(dev_pm_qos_mtx);
   lock(s_active#54);

  *** DEADLOCK ***

To avoid that, remove the calls to functions mentioned above from
under dev_pm_qos_mtx and introduce a separate lock to prevent races
between functions that add or remove device PM QoS sysfs attributes
from happening.
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      0f703069
  23. 30 3月, 2013 7 次提交
  25. 27 3月, 2013 7 次提交
  27. 22 3月, 2013 1 次提交
    • S
      regmap: don't corrupt work buffer in _regmap_raw_write() · bc8ce4af
      由 Stephen Warren 提交于 
      _regmap_raw_write() contains code to call regcache_write() to write
values to the cache. That code calls memcpy() to copy the value data to
the start of the work_buf. However, at least when _regmap_raw_write() is
called from _regmap_bus_raw_write(), the value data is in the work_buf,
and this memcpy() operation may over-write part of that value data,
depending on the value of reg_bytes + pad_bytes. At least when using
reg_bytes==1 and pad_bytes==0, corruption of the value data does occur.

To solve this, remove the memcpy() operation, and modify the subsequent
.parse_val() call to parse the original value buffer directly.

At least in the case of 8-bit register address and 16-bit values, and
writes of single registers at a time, this memcpy-then-parse combination
used to cancel each-other out; for a work-buffer containing xx 89 03,
the memcpy changed it to 89 03 03, and the parse_val changed it back to
89 89 03, thus leaving the value uncorrupted. This appears completely
accidental though. Since commit 8a819ff8 "regmap: core: Split out in
place value parsing", .parse_val only returns the parsed value, and does
not modify the buffer, and hence does not (accidentally) undo the
corruption caused by memcpy(). This caused bogus values to get written
to HW, thus preventing e.g. audio playback on systems with a WM8903
CODEC. This patch fixes that.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
      bc8ce4af
  29. 19 3月, 2013 1 次提交
  31. 16 3月, 2013 1 次提交
  33. 14 3月, 2013 1 次提交
    • L
      regmap: cache Fix regcache-rbtree sync · 8abac3ba
      由 Lars-Peter Clausen 提交于 
      The last register block, which falls into the specified range, is not handled
correctly. The formula which calculates the number of register which should be
synced is inverse (and off by one). E.g. if all registers in that block should
be synced only one is synced, and if only one should be synced all (but one) are
synced. To calculate the number of registers that need to be synced we need to
subtract the number of the first register in the block from the max register
number and add one. This patch updates the code accordingly.

The issue was introduced in commit ac8d91c8 ("regmap: Supply ranges to the sync
operations").
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org
      8abac3ba