From: Dan Carpenter <error27@gmail.com>
Date: Wed, 23 Jun 2010 11:19:55 +0000 (+0200)
Subject: drm/i915: take struct_mutex in i915_dma_cleanup()
X-Git-Tag: v2.6.35-rc4~10^2~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ee0c6bfbd602cdad2ab1780061b3b1a9108cbd6c;p=pandora-kernel.git

drm/i915: take struct_mutex in i915_dma_cleanup()

intel_cleanup_ring_buffer() calls drm_gem_object_unreference() (as
opposed to drm_gem_object_unreference_unlocked()) so it needs to be
called with "struct_mutex" held.  If we don't hold the lock, it triggers
a BUG_ON(!mutex_is_locked(&dev->struct_mutex));

I also audited the other places that call intel_cleanup_ring_buffer()
and they all hold the lock so they're OK.

This was introduced in: 8187a2b70e3 "drm/i915: introduce
intel_ring_buffer structure (V2)" and it's a regression from v2.6.34.

Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=16247

Signed-off-by: Dan Carpenter <error27@gmail.com>
Reported-by: Benny Halevy <bhalevy@panasas.com>
Tested-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
---

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