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 | 55 +++++---------------------------- 1 file changed, 8 insertions(+), 47 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 11e10e0d628c..8859feb7d131 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -777,7 +777,6 @@ 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 { @@ -787,34 +786,10 @@ 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 * @@ -1153,7 +1128,6 @@ static int __i915_vma_get_pages(struct i915_vma *vma) { struct sg_table *pages; - int ret;
/* * The vma->pages are only valid within the lifespan of the borrowed @@ -1186,18 +1160,16 @@ __i915_vma_get_pages(struct i915_vma *vma) break; }
- ret = 0; if (IS_ERR(pages)) { - ret = PTR_ERR(pages); - pages = NULL; drm_err(&vma->vm->i915->drm, - "Failed to get pages for VMA view type %u (%d)!\n", - vma->ggtt_view.type, ret); + "Failed to get pages for VMA view type %u (%ld)!\n", + vma->ggtt_view.type, PTR_ERR(pages)); + return PTR_ERR(pages); }
vma->pages = pages;
- return ret; + return 0; }
I915_SELFTEST_EXPORT int i915_vma_get_pages(struct i915_vma *vma) @@ -1229,25 +1201,14 @@ 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); - GEM_BUG_ON(atomic_read(&vma->pages_count) < count);
if (atomic_sub_return(count, &vma->pages_count) == 0) { - /* - * The atomic_sub_return is a read barrier for the READ_ONCE of - * vma->pages above. - * - * READ_ONCE is safe because this is either called from the same - * function (i915_vma_pin_ww), or guarded by vma->vm->mutex. - * - * TODO: We're leaving vma->pages dangling, until vma->obj->resv - * lock is required. - */ - if (pages != vma->obj->mm.pages) { - sg_free_table(pages); - kfree(pages); + if (vma->pages != vma->obj->mm.pages) { + sg_free_table(vma->pages); + kfree(vma->pages); } + vma->pages = NULL;
i915_gem_object_unpin_pages(vma->obj); }