[RFC PATCH 076/162] drm/i915: Untangle the vma pages_mutex

[Matthew Auld]

From: Thomas Hellström <thomas.hellst...@intel.com>

Move the vma pages_mutex out of the way from the object ww locks.

Signed-off-by: Thomas Hellström <thomas.hellst...@intel.com>
Cc: Matthew Auld <matthew.a...@intel.com>
---
 drivers/gpu/drm/i915/i915_vma.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 0c7e4191811a..7243ab593aec 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -792,28 +792,30 @@ static int vma_get_pages(struct i915_vma *vma)
        if (atomic_add_unless(&vma->pages_count, 1, 0))
                return 0;
 
+       if (vma->obj) {
+               err = i915_gem_object_pin_pages(vma->obj);
+               if (err)
+                       return err;
+       }
+
        /* Allocations ahoy! */
-       if (mutex_lock_interruptible(&vma->pages_mutex))
-               return -EINTR;
+       if (mutex_lock_interruptible(&vma->pages_mutex)) {
+               err = -EINTR;
+               goto unpin;
+       }
 
        if (!atomic_read(&vma->pages_count)) {
-               if (vma->obj) {
-                       err = i915_gem_object_pin_pages(vma->obj);
-                       if (err)
-                               goto unlock;
-               }
-
                err = vma->ops->set_pages(vma);
-               if (err) {
-                       if (vma->obj)
-                               i915_gem_object_unpin_pages(vma->obj);
+               if (err)
                        goto unlock;
-               }
        }
        atomic_inc(&vma->pages_count);
 
 unlock:
        mutex_unlock(&vma->pages_mutex);
+unpin:
+       if (err && vma->obj)
+               __i915_gem_object_unpin_pages(vma->obj);
 
        return err;
 }
@@ -826,10 +828,10 @@ static void __vma_put_pages(struct i915_vma *vma, 
unsigned int count)
        if (atomic_sub_return(count, &vma->pages_count) == 0) {
                vma->ops->clear_pages(vma);
                GEM_BUG_ON(vma->pages);
-               if (vma->obj)
-                       i915_gem_object_unpin_pages(vma->obj);
        }
        mutex_unlock(&vma->pages_mutex);
+       if (vma->obj)
+               i915_gem_object_unpin_pages(vma->obj);
 }
 
 static void vma_put_pages(struct i915_vma *vma)
-- 
2.26.2

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