releases/3.4.2/drm-radeon-fix-vm-deadlocks-on-cayman.patch

   1 From bb4091558228ff4a3e02328c931e683fc7f08722 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Christian=20K=C3=B6nig?= <deathsimple@vodafone.de>
   3 Date: Sun, 3 Jun 2012 16:09:43 +0200
   4 Subject: drm/radeon: fix vm deadlocks on cayman
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 From: Christian König <deathsimple@vodafone.de>
  10
  11 commit bb4091558228ff4a3e02328c931e683fc7f08722 upstream.
  12
  13 Locking mutex in different orders just screams for
  14 deadlocks, and some testing showed that it is actually
  15 quite easy to trigger them.
  16
  17 Signed-off-by: Christian König <deathsimple@vodafone.de>
  18 Reviewed-by: Jerome Glisse <jglisse@redhat.com>
  19 Signed-off-by: Dave Airlie <airlied@redhat.com>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21
  22 ---
  23  drivers/gpu/drm/radeon/radeon_gart.c |   19 ++++++++++++-------
  24  1 file changed, 12 insertions(+), 7 deletions(-)
  25
  26 --- a/drivers/gpu/drm/radeon/radeon_gart.c
  27 +++ b/drivers/gpu/drm/radeon/radeon_gart.c
  28 @@ -478,12 +478,18 @@ int radeon_vm_bo_add(struct radeon_devic
  29
  30         mutex_lock(&vm->mutex);
  31         if (last_pfn > vm->last_pfn) {
  32 -               /* grow va space 32M by 32M */
  33 -               unsigned align = ((32 << 20) >> 12) - 1;
  34 +               /* release mutex and lock in right order */
  35 +               mutex_unlock(&vm->mutex);
  36                 radeon_mutex_lock(&rdev->cs_mutex);
  37 -               radeon_vm_unbind_locked(rdev, vm);
  38 +               mutex_lock(&vm->mutex);
  39 +               /* and check again */
  40 +               if (last_pfn > vm->last_pfn) {
  41 +                       /* grow va space 32M by 32M */
  42 +                       unsigned align = ((32 << 20) >> 12) - 1;
  43 +                       radeon_vm_unbind_locked(rdev, vm);
  44 +                       vm->last_pfn = (last_pfn + align) & ~align;
  45 +               }
  46                 radeon_mutex_unlock(&rdev->cs_mutex);
  47 -               vm->last_pfn = (last_pfn + align) & ~align;
  48         }
  49         head = &vm->va;
  50         last_offset = 0;
  51 @@ -597,8 +603,8 @@ int radeon_vm_bo_rmv(struct radeon_devic
  52         if (bo_va == NULL)
  53                 return 0;
  54
  55 -       mutex_lock(&vm->mutex);
  56         radeon_mutex_lock(&rdev->cs_mutex);
  57 +       mutex_lock(&vm->mutex);
  58         radeon_vm_bo_update_pte(rdev, vm, bo, NULL);
  59         radeon_mutex_unlock(&rdev->cs_mutex);
  60         list_del(&bo_va->vm_list);
  61 @@ -643,9 +649,8 @@ void radeon_vm_fini(struct radeon_device
  62         struct radeon_bo_va *bo_va, *tmp;
  63         int r;
  64
  65 -       mutex_lock(&vm->mutex);
  66 -
  67         radeon_mutex_lock(&rdev->cs_mutex);
  68 +       mutex_lock(&vm->mutex);
  69         radeon_vm_unbind_locked(rdev, vm);
  70         radeon_mutex_unlock(&rdev->cs_mutex);
  71