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  1. 18 Mar, 2014 13 commits
  3. 17 Mar, 2014 7 commits
  5. 16 Mar, 2014 20 commits
    • Linus Torvalds's avatar
      Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 59bf6c3c
      Linus Torvalds authored 
      Pull scheduler fixes from Ingo Molnar:
 "Three small fixes"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/clock: Prevent tracing recursion in sched_clock_cpu()
  stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus()
  sched/deadline: Deny unprivileged users to set/change SCHED_DEADLINE policy
      59bf6c3c
    • Linus Torvalds's avatar
      Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · b44eeb4d
      Linus Torvalds authored 
      Pull perf fixes from Ingo Molnar:
 "Misc smaller fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix leak in uncore_type_init failure paths
  perf machine: Use map as success in ip__resolve_ams
  perf symbols: Fix crash in elf_section_by_name
  perf trace: Decode architecture-specific signal numbers
      b44eeb4d
    • Michael Kerrisk's avatar
      ipc: Fix 2 bugs in msgrcv() MSG_COPY implementation · 4f87dac3
      Michael Kerrisk authored 
      While testing and documenting the msgrcv() MSG_COPY flag that Stanislav
Kinsbursky added in commit 4a674f34 ("ipc: introduce message queue
copy feature" => kernel 3.8), I discovered a couple of bugs in the
implementation.  The two bugs concern MSG_COPY interactions with other
msgrcv() flags, namely:

 (A) MSG_COPY + MSG_EXCEPT
 (B) MSG_COPY + !IPC_NOWAIT

The bugs are distinct (and the fix for the first one is obvious),
however my fix for both is a single-line patch, which is why I'm
combining them in a single mail, rather than writing two mails+patches.

 ===== (A) MSG_COPY + MSG_EXCEPT =====

With the addition of the MSG_COPY flag, there are now two msgrcv()
flags--MSG_COPY and MSG_EXCEPT--that modify the meaning of the 'msgtyp'
argument in unrelated ways.  Specifying both in the same call is a
logical error that is currently permitted, with the effect that MSG_COPY
has priority and MSG_EXCEPT is ignored.  The call should give an error
if both flags are specified.  The patch below implements that behavior.

 ===== (B) (B) MSG_COPY + !IPC_NOWAIT =====

The test code that was submitted in commit 3a665531 ("selftests: IPC
message queue copy feature test") shows MSG_COPY being used in
conjunction with IPC_NOWAIT.  In other words, if there is no message at
the position 'msgtyp'.  return immediately with the error in ENOMSG.

What was not (fully) tested is the behavior if MSG_COPY is specified
*without* IPC_NOWAIT, and there is an odd behavior.  If the queue
contains less than 'msgtyp' messages, then the call blocks until the
next message is written to the queue.  At that point, the msgrcv() call
returns a copy of the newly added message, regardless of whether that
message is at the ordinal position 'msgtyp'.  This is clearly bogus, and
problematic for applications that might want to make use of the MSG_COPY
flag.

I considered the following possible solutions to this problem:

 (1) Force the call to block until a message *does* appear at the
     position 'msgtyp'.

 (2) If the MSG_COPY flag is specified, the kernel should implicitly add
     IPC_NOWAIT, so that the call fails with ENOMSG for this case.

 (3) If the MSG_COPY flag is specified, but IPC_NOWAIT is not, generate
     an error (probably, EINVAL is the right one).

I do not know if any application would really want to have the
functionality of solution (1), especially since an application can
determine in advance the number of messages in the queue using msgctl()
IPC_STAT.  Obviously, this solution would be the most work to implement.

Solution (2) would have the effect of silently fixing any applications
that tried to employ broken behavior.  However, it would mean that if we
later decided to implement solution (1), then user-space could not
easily detect what the kernel supports (but, since I'm somewhat doubtful
that solution (1) is needed, I'm not sure that this is much of a
problem).

Solution (3) would have the effect of informing broken applications that
they are doing something broken.  The downside is that this would cause
a ABI breakage for any applications that are currently employing the
broken behavior.  However:

a) Those applications are almost certainly not getting the results they
   expect.
b) Possibly, those applications don't even exist, because MSG_COPY is
   currently hidden behind CONFIG_CHECKPOINT_RESTORE.

The upside of solution (3) is that if we later decided to implement
solution (1), user-space could determine what the kernel supports, via
the error return.

In my view, solution (3) is mildly preferable to solution (2), and
solution (1) could still be done later if anyone really cares.  The
patch below implements solution (3).

PS.  For anyone out there still listening, it's the usual story:
documenting an API (and the thinking about, and the testing of the API,
that documentation entails) is the one of the single best ways of
finding bugs in the API, as I've learned from a lot of experience.  Best
to do that documentation before releasing the API.
Signed-off-by: default avatarMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4f87dac3
    • David Herrmann's avatar
      Merge branch 'drm-minor' into drm-next · 07b48c3a
      David Herrmann authored 
      Fix minor conflicts with drm-anon:
 - allocation/free order
 - drm_device header cleanups
      07b48c3a
    • David Herrmann's avatar
      Merge branch 'drm-anon' into drm-next · afab4463
      David Herrmann authored
      afab4463
    • David Herrmann's avatar
      drm: make minors independent of global lock · 0d639883
      David Herrmann authored 
      We used to protect minor-lookup and setup by the global drm lock. To
continue our attempts of dropping drm_global_mutex, this patch makes the
minor management independent of it. Furthermore, we make it all atomic and
switch to spin-locks instead of a mutex.

Now that minor-lookup is independent, we also move the
"drm_is_unplugged()" test into the minor-lookup path. There is no reason
to ever return a minor for unplugged objects, so keep that logic internal.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      0d639883
    • David Herrmann's avatar
      drm: inline drm_minor_get_id() · 7d86cf1a
      David Herrmann authored 
      We can significantly simplify this helper by using plain multiplication.
Note that we converted the minor-type to an enum earlier so this didn't
work before.

We also fix a minor range-bug here: the limit argument of idr_alloc() is
*exclusive*, not inclusive, so we should use 64 instead of 63 as offset.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      7d86cf1a
    • David Herrmann's avatar
      drm: coding-style fixes in minor handling · 1abbc437
      David Herrmann authored 
      Properly name goto-labels, remove empty lines and use DRM_ERROR if
possible.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      1abbc437
    • David Herrmann's avatar
      drm: remove redundant minor->device field · 5817878c
      David Herrmann authored 
      Whenever we access minor->device, we are in a minor->kdev->...->fops
callback so the minor->kdev pointer *must* be valid. Thus, simply use
minor->kdev->devt instead of minor->device and remove the redundant field.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      5817878c
    • David Herrmann's avatar
      drm: remove unneeded #ifdef CONFIG_DEBUGFS · cb0f9323
      David Herrmann authored 
      No need to check for DEBUGFS, we already have dummy-fallbacks in our
headers.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      cb0f9323
    • David Herrmann's avatar
      drm: rename drm_unplug/get_minor() to drm_minor_register/unregister() · afcdbc86
      David Herrmann authored 
      drm_get_minor() no longer allocates objects, and drm_unplug_minor() is now
the exact reverse of it. Rename it to _register/unregister() so their
name actually says what they do.

Furthermore, remove the direct minor-ptr and instead pass the minor-type.
This way we know the actual slot of the minor and can reset it if
required.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      afcdbc86
    • David Herrmann's avatar
      drm: move drm_put_minor() to drm_minor_free() · bd9dfa98
      David Herrmann authored 
      _put/get() are used for ref-counting, which we clearly don't do here.
Rename it to _free() and also use the common drm_minor_* prefix.
Furthermore, avoid passing the minor directly but instead use the type
like the other functions do, this allows us to reset the slot.

We also drop the redundant call to drm_unplug_minor() as drm_minor_free()
is only used from paths were that has already be called.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      bd9dfa98
    • David Herrmann's avatar
      drm: allocate minors early · 05b701f6
      David Herrmann authored 
      Instead of waiting for device-registration, we now allocate minor-objects
during device allocation. The minors are not registered or assigned an ID.
This is still postponed to device-registration.

While at it, remove the superfluous output-parameter in drm_get_minor().

The reason for this early allocation is to make
dev->primary/control/render available atomically. So once the device is
alive, all of them are already set and we never have the situation where
one of them is set after another (they're either NULL or set, but never
changed). This will eventually allow us to reduce minor-ID allocation to
one base-ID instead of a single ID for each.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      05b701f6
    • David Herrmann's avatar
      drm: add minor-lookup/release helpers · 1616c525
      David Herrmann authored 
      Instead of accessing drm_minors_idr directly, this adds a small helper to
hide the internals. This will help us later to remove the drm_global_mutex
requirement for minor-lookup.

Furthermore, this also makes sure that minor->dev is always valid and
takes a reference-count to the device as long as the minor is used in an
open-file. This way, "struct file*"->private_data->dev is guaranteed to be
valid (which it has to, as we cannot reset it).
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      1616c525
    • David Herrmann's avatar
      drm: provide device-refcount · 099d1c29
      David Herrmann authored 
      Lets not trick ourselves into thinking "drm_device" objects are not
ref-counted. That's just utterly stupid. We manage "drm_minor" objects on
each drm-device and each minor can have an unlimited number of open
handles. Each of these handles has the drm_minor (and thus the drm_device)
as private-data in the file-handle. Therefore, we may not destroy
"drm_device" until all these handles are closed.

It is *not* possible to reset all these pointers atomically and restrict
access to them, and this is *not* how this is done! Instead, we use
ref-counts to make sure the object is valid and not freed.

Note that we currently use "dev->open_count" for that, which is *exactly*
the same as a reference-count, just open coded. So this patch doesn't
change any semantics on DRM devices (well, this patch just introduces the
ref-count, anyway. Follow-up patches will replace open_count by it).

Also note that generic VFS revoke support could allow us to drop this
ref-count again. We could then just synchronously disable any fops->xy()
calls. However, this is not the case, yet, and no such patches are
in sight (and I seriously question the idea of dropping the ref-cnt
again).
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      099d1c29
    • David Herrmann's avatar
      drm: turn DRM_MINOR_* into enum · cb8a239b
      David Herrmann authored 
      Use enum for DRM_MINOR_* constants to avoid hard-coding the IDs.
Furthermore, add a DRM_MINOR_CNT so we can perform range-checks in
follow-ups.

This changes the IDs of the minor-types by -1, but they're not used as
indices so this is fine.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      cb8a239b
    • David Herrmann's avatar
      drm: remove unused DRM_MINOR_UNASSIGNED · b9a0d15c
      David Herrmann authored 
      This constant is unused, remove it.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      b9a0d15c
    • David Herrmann's avatar
      drm: skip redundant minor-lookup in open path · f4aede2e
      David Herrmann authored 
      The drm_open_helper() function is only used internally for drm_open() so
we can safely pass in the minor-object directly instead of the minor-id.
This way, we avoid the additional minor IDR lookup, which we already do
twice in drm_stub_open() and drm_open().
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      f4aede2e
    • David Herrmann's avatar
      drm: group dev-lifetime related members · 45e212d2
      David Herrmann authored 
      These members are all managed by DRM-core, lets group them together so
they're not split across the whole device.
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      45e212d2
    • David Herrmann's avatar
      drm: init TTM dev_mapping in ttm_bo_device_init() · 44d847b7
      David Herrmann authored 
      With dev->anon_inode we have a global address_space ready for operation
right from the beginning. Therefore, there is no need to do a delayed
setup with TTM. Instead, set dev_mapping during initialization in
ttm_bo_device_init() and remove any "if (dev_mapping)" conditions.

Cc: Dave Airlie <airlied@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      44d847b7
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