Now that we require the object lock for all ops, some code handling race conditions can be removed.
This is required to not take short-term pins inside execbuf.
Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Acked-by: Niranjana Vishwanathapura niranjana.vishwanathapura@intel.com --- drivers/gpu/drm/i915/i915_vma.c | 40 +++++---------------------------- 1 file changed, 5 insertions(+), 35 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 100739b3e084..3236cf1c1400 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -776,7 +776,6 @@ i915_vma_detach(struct i915_vma *vma) static bool try_qad_pin(struct i915_vma *vma, unsigned int flags) { unsigned int bound; - bool pinned = true;
bound = atomic_read(&vma->flags); do { @@ -786,34 +785,10 @@ static bool try_qad_pin(struct i915_vma *vma, unsigned int flags) if (unlikely(bound & (I915_VMA_OVERFLOW | I915_VMA_ERROR))) return false;
- if (!(bound & I915_VMA_PIN_MASK)) - goto unpinned; - GEM_BUG_ON(((bound + 1) & I915_VMA_PIN_MASK) == 0); } while (!atomic_try_cmpxchg(&vma->flags, &bound, bound + 1));
return true; - -unpinned: - /* - * If pin_count==0, but we are bound, check under the lock to avoid - * racing with a concurrent i915_vma_unbind(). - */ - mutex_lock(&vma->vm->mutex); - do { - if (unlikely(bound & (I915_VMA_OVERFLOW | I915_VMA_ERROR))) { - pinned = false; - break; - } - - if (unlikely(flags & ~bound)) { - pinned = false; - break; - } - } while (!atomic_try_cmpxchg(&vma->flags, &bound, bound + 1)); - mutex_unlock(&vma->vm->mutex); - - return pinned; }
static struct scatterlist * @@ -1194,13 +1169,7 @@ __i915_vma_get_pages(struct i915_vma *vma) vma->ggtt_view.type, ret); }
- pages = xchg(&vma->pages, pages); - - /* did we race against a put_pages? */ - if (pages && pages != vma->obj->mm.pages) { - sg_free_table(vma->pages); - kfree(vma->pages); - } + vma->pages = pages;
return ret; } @@ -1234,13 +1203,14 @@ I915_SELFTEST_EXPORT int i915_vma_get_pages(struct i915_vma *vma) static void __vma_put_pages(struct i915_vma *vma, unsigned int count) { /* We allocate under vma_get_pages, so beware the shrinker */ - struct sg_table *pages = READ_ONCE(vma->pages); + struct sg_table *pages = vma->pages;
GEM_BUG_ON(atomic_read(&vma->pages_count) < count);
if (atomic_sub_return(count, &vma->pages_count) == 0) { - if (pages == cmpxchg(&vma->pages, pages, NULL) && - pages != vma->obj->mm.pages) { + vma->pages = NULL; + + if (pages != vma->obj->mm.pages) { sg_free_table(pages); kfree(pages); }