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.lankho...@linux.intel.com>
Acked-by: Niranjana Vishwanathapura <niranjana.vishwanathap...@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);
}
--
2.34.1
