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  1. Mar 26, 2020
    • Daniel Vetter's avatar
      drm/udl: Use drmm_add_final_kfree · d0c116ad
      Daniel Vetter authored 
      

With this we can drop the final kfree from the release function.

v2: We need drm_dev_put to unroll the driver creation (once
drm_dev_init and drmm_add_final_kfree suceeded), otherwise
the drmm_ magic doesn't happen.

v3: Actually squash in the fixup (Laurent).

Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-7-daniel.vetter@ffwll.ch
      d0c116ad
    • Daniel Vetter's avatar
      drm/mipi_dbi: Use drmm_add_final_kfree in all drivers · f5ad671b
      Daniel Vetter authored 
      

They all share mipi_dbi_release so we need to switch them all
together. With this we can drop the final kfree from the release
function.

Aside, I think we could perhaps have a tiny additional helper for
these mipi_dbi drivers, the first few lines around devm_drm_dev_init
are all the same (except for the drm_driver pointer).

Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Reviewed-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Tested-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
Cc: David Lechner <david@lechnology.com>
Cc: Kamlesh Gurudasani <kamlesh.gurudasani@gmail.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-6-daniel.vetter@ffwll.ch
      f5ad671b
    • Daniel Vetter's avatar
      drm: Set final_kfree in drm_dev_alloc · 6f365e56
      Daniel Vetter authored 
      I also did a full review of all callers, and only the xen driver
forgot to call drm_dev_put in the failure path. Fix that up too.

v2: I noticed that xen has a drm_driver.release hook, and uses
drm_dev_alloc(). We need to remove the kfree from
xen_drm_drv_release().

bochs also has a release hook, but leaked the drm_device ever since

commit 0a6659bd
Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Tue Dec 17 18:04:46 2013 +0100

    drm/bochs: new driver

This patch here fixes that leak.

Same for virtio, started leaking with

commit b1df3a2b


Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Tue Feb 11 14:58:04 2020 +0100

    drm/virtio: add drm_driver.release callback.

Acked-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Reviewed-by: default avatarOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: xen-devel@lists.xenproject.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-5-daniel.vetter@ffwll.ch
      6f365e56
    • Daniel Vetter's avatar
      drm: add managed resources tied to drm_device · c6603c74
      Daniel Vetter authored 
      

We have lots of these. And the cleanup code tends to be of dubious
quality. The biggest wrong pattern is that developers use devm_, which
ties the release action to the underlying struct device, whereas
all the userspace visible stuff attached to a drm_device can long
outlive that one (e.g. after a hotunplug while userspace has open
files and mmap'ed buffers). Give people what they want, but with more
correctness.

Mostly copied from devres.c, with types adjusted to fit drm_device and
a few simplifications - I didn't (yet) copy over everything. Since
the types don't match code sharing looked like a hopeless endeavour.

For now it's only super simplified, no groups, you can't remove
actions (but kfree exists, we'll need that soon). Plus all specific to
drm_device ofc, including the logging. Which I didn't bother to make
compile-time optional, since none of the other drm logging is compile
time optional either.

One tricky bit here is the chicken&egg between allocating your
drm_device structure and initiliazing it with drm_dev_init. For
perfect onion unwinding we'd need to have the action to kfree the
allocation registered before drm_dev_init registers any of its own
release handlers. But drm_dev_init doesn't know where exactly the
drm_device is emebedded into the overall structure, and by the time it
returns it'll all be too late. And forcing drivers to be able clean up
everything except the one kzalloc is silly.

Work around this by having a very special final_kfree pointer. This
also avoids troubles with the list head possibly disappearing from
underneath us when we release all resources attached to the
drm_device.

v2: Do all the kerneldoc at the end, to avoid lots of fairly pointless
shuffling while getting everything into shape.

v3: Add static to add/del_dr (Neil)
Move typo fix to the right patch (Neil)

v4: Enforce contract for drmm_add_final_kfree:

Use ksize() to check that the drm_device is indeed contained somewhere
in the final kfree(). Because we need that or the entire managed
release logic blows up in a pile of use-after-frees. Motivated by a
discussion with Laurent.

v5: Review from Laurent:
- %zu instead of casting size_t
- header guards
- sorting of includes
- guarding of data assignment if we didn't allocate it for a NULL
  pointer
- delete spurious newline
- cast void* data parameter correctly in ->release call, no idea how
  this even worked before

v6: Review from Sam
- Add the kerneldoc for the managed sub-struct back in, even if it
  doesn't show up in the generated html somehow.
- Explain why __always_inline.
- Fix bisectability around the final kfree() in drm_dev_relase(). This
  is just interim code which will disappear again.
- Some whitespace polish.
- Add debug output when drmm_add_action or drmm_kmalloc fail.

v7: My bisectability fix wasn't up to par as noticed by smatch.

v8: Remove unecessary {} around if else

v9: Use kstrdup_const, which requires kfree_const and introducing a free_dr()
helper (Thomas).

v10: kfree_const goes boom on the plain "kmalloc" assignment, somehow
we need to wrap that in kstrdup_const() too!! Also renumber revision
log, I somehow reset it midway thruh.

Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Neil Armstrong <narmstrong@baylibre.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200324124540.3227396-1-daniel.vetter@ffwll.ch
      c6603c74
    • Daniel Vetter's avatar
      drm/i915: Don't clear drvdata in ->release · 0ce542f7
      Daniel Vetter authored 
      For two reasons:

- The driver core clears this already for us after we're unloaded in
  __device_release_driver().

- It's way too late, the drm_device ->release callback might massively
  outlive the underlying physical device, since a drm_device can be
  kept alive by open drm_file or well really anything else userspace
  is still hanging onto. So if we clear this ourselves, we should
  clear it in the pci ->remove callback, not in the drm_device
  ->release callback.

Looking at git history this was fixed in the driver core with

commit 0998d063


Author: Hans de Goede <hdegoede@redhat.com>
Date:   Wed May 23 00:09:34 2012 +0200

    device-core: Ensure drvdata = NULL when no driver is bound

v2: Cite the core fix in the commit message (Chris).

v3: Fix commit message and unused variable warning (Jani).

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-3-daniel.vetter@ffwll.ch
      0ce542f7
    • Daniel Vetter's avatar
      mm/sl[uo]b: export __kmalloc_track(_node)_caller · fd7cb575
      Daniel Vetter authored 
      

slab does this already, and I want to use this in a memory allocation
tracker in drm for stuff that's tied to the lifetime of a drm_device,
not the underlying struct device. Kinda like devres, but for drm.

Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-2-daniel.vetter@ffwll.ch
      fd7cb575
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