[PATCH 1/9] drm/i915: Refactor testing obj->mm.pages

Chris Wilson
2017-10-13T20:26:32Z

Since we occasionally stuff an error pointer into obj->mm.pages for a
semi-permanent or even permanent failure, we have to be more careful and
not just test against NULL when deciding if the object has a complete
set of its concurrent pages.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 10 ++++++++--
drivers/gpu/drm/i915/i915_gem.c | 19 ++++++++++---------
drivers/gpu/drm/i915/i915_gem_clflush.c | 1 +
drivers/gpu/drm/i915/i915_gem_render_state.c | 2 +-
drivers/gpu/drm/i915/i915_gem_shrinker.c | 10 +++++-----
drivers/gpu/drm/i915/i915_gem_tiling.c | 2 +-
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
7 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c7b2ca6aff05..48be1d3c1d33 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3565,10 +3565,16 @@ i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
return __i915_gem_object_get_pages(obj);
}

+static inline bool
+i915_gem_object_has_pages(struct drm_i915_gem_object *obj)
+{
+ return !IS_ERR_OR_NULL(READ_ONCE(obj->mm.pages));
+}
+
static inline void
__i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
{
- GEM_BUG_ON(!obj->mm.pages);
+ GEM_BUG_ON(!i915_gem_object_has_pages(obj));

atomic_inc(&obj->mm.pages_pin_count);
}
@@ -3582,8 +3588,8 @@ i915_gem_object_has_pinned_pages(struct drm_i915_gem_object *obj)
static inline void
__i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
{
+ GEM_BUG_ON(!i915_gem_object_has_pages(obj));
GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
- GEM_BUG_ON(!obj->mm.pages);

atomic_dec(&obj->mm.pages_pin_count);
}
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 20fcac37c85a..0c42ec876de0 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2196,7 +2196,7 @@ void __i915_gem_object_invalidate(struct drm_i915_gem_object *obj)
struct address_space *mapping;

lockdep_assert_held(&obj->mm.lock);
- GEM_BUG_ON(obj->mm.pages);
+ GEM_BUG_ON(i915_gem_object_has_pages(obj));

switch (obj->mm.madv) {
case I915_MADV_DONTNEED:
@@ -2259,7 +2259,7 @@ void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
return;

GEM_BUG_ON(obj->bind_count);
- if (!READ_ONCE(obj->mm.pages))
+ if (!i915_gem_object_has_pages(obj))
return;

/* May be called by shrinker from within get_pages() (on another bo) */
@@ -2563,7 +2563,7 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
if (err)
return err;

- if (unlikely(IS_ERR_OR_NULL(obj->mm.pages))) {
+ if (unlikely(!i915_gem_object_has_pages(obj))) {
GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));

err = ____i915_gem_object_get_pages(obj);
@@ -2648,7 +2648,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
type &= ~I915_MAP_OVERRIDE;

if (!atomic_inc_not_zero(&obj->mm.pages_pin_count)) {
- if (unlikely(IS_ERR_OR_NULL(obj->mm.pages))) {
+ if (unlikely(!i915_gem_object_has_pages(obj))) {
GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));

ret = ____i915_gem_object_get_pages(obj);
@@ -2660,7 +2660,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
atomic_inc(&obj->mm.pages_pin_count);
pinned = false;
}
- GEM_BUG_ON(!obj->mm.pages);
+ GEM_BUG_ON(!i915_gem_object_has_pages(obj));

ptr = page_unpack_bits(obj->mm.mapping, &has_type);
if (ptr && has_type != type) {
@@ -2715,7 +2715,7 @@ i915_gem_object_pwrite_gtt(struct drm_i915_gem_object *obj,
* allows it to avoid the cost of retrieving a page (either swapin
* or clearing-before-use) before it is overwritten.
*/
- if (READ_ONCE(obj->mm.pages))
+ if (i915_gem_object_has_pages(obj))
return -ENODEV;

/* Before the pages are instantiated the object is treated as being
@@ -4280,7 +4280,7 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
if (err)
goto out;

- if (obj->mm.pages &&
+ if (i915_gem_object_has_pages(obj) &&
i915_gem_object_is_tiled(obj) &&
dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
if (obj->mm.madv == I915_MADV_WILLNEED) {
@@ -4299,7 +4299,8 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
obj->mm.madv = args->madv;

/* if the object is no longer attached, discard its backing storage */
- if (obj->mm.madv == I915_MADV_DONTNEED && !obj->mm.pages)
+ if (obj->mm.madv == I915_MADV_DONTNEED &&
+ !i915_gem_object_has_pages(obj))
i915_gem_object_truncate(obj);

args->retained = obj->mm.madv != __I915_MADV_PURGED;
@@ -4516,7 +4517,7 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
if (WARN_ON(i915_gem_object_has_pinned_pages(obj)))
atomic_set(&obj->mm.pages_pin_count, 0);
__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
- GEM_BUG_ON(obj->mm.pages);
+ GEM_BUG_ON(i915_gem_object_has_pages(obj));

if (obj->base.import_attach)
drm_prime_gem_destroy(&obj->base, NULL);
diff --git a/drivers/gpu/drm/i915/i915_gem_clflush.c b/drivers/gpu/drm/i915/i915_gem_clflush.c
index 8a04d33055be..f663cd919795 100644
--- a/drivers/gpu/drm/i915/i915_gem_clflush.c
+++ b/drivers/gpu/drm/i915/i915_gem_clflush.c
@@ -70,6 +70,7 @@ static const struct dma_fence_ops i915_clflush_ops = {

static void __i915_do_clflush(struct drm_i915_gem_object *obj)
{
+ GEM_BUG_ON(!i915_gem_object_has_pages(obj));
drm_clflush_sg(obj->mm.pages);
intel_fb_obj_flush(obj, ORIGIN_CPU);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
index 4dd4c2159a92..3703dc91eeda 100644
--- a/drivers/gpu/drm/i915/i915_gem_render_state.c
+++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
@@ -229,7 +229,7 @@ int i915_gem_render_state_emit(struct drm_i915_gem_request *req)
return 0;

/* Recreate the page after shrinking */
- if (!so->vma->obj->mm.pages)
+ if (!i915_gem_object_has_pages(so->vma->obj))
so->batch_offset = -1;

ret = i915_vma_pin(so->vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 74002b2d1b6f..b5c87d89777b 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -97,7 +97,7 @@ static bool swap_available(void)

static bool can_release_pages(struct drm_i915_gem_object *obj)
{
- if (!obj->mm.pages)
+ if (!i915_gem_object_has_pages(obj))
return false;

/* Consider only shrinkable ojects. */
@@ -129,7 +129,7 @@ static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
{
if (i915_gem_object_unbind(obj) == 0)
__i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
- return !READ_ONCE(obj->mm.pages);
+ return !i915_gem_object_has_pages(obj);
}

/**
@@ -247,7 +247,7 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
/* May arrive from get_pages on another bo */
mutex_lock_nested(&obj->mm.lock,
I915_MM_SHRINKER);
- if (!obj->mm.pages) {
+ if (!i915_gem_object_has_pages(obj)) {
__i915_gem_object_invalidate(obj);
list_del_init(&obj->global_link);
count += obj->base.size >> PAGE_SHIFT;
@@ -413,7 +413,7 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
*/
unbound = bound = unevictable = 0;
list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link) {
- if (!obj->mm.pages)
+ if (!i915_gem_object_has_pages(obj))
continue;

if (!can_release_pages(obj))
@@ -422,7 +422,7 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
unbound += obj->base.size >> PAGE_SHIFT;
}
list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
- if (!obj->mm.pages)
+ if (!i915_gem_object_has_pages(obj))
continue;

if (!can_release_pages(obj))
diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index fb5231f98c0d..1294cf695df0 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -269,7 +269,7 @@ i915_gem_object_set_tiling(struct drm_i915_gem_object *obj,
* due to the change in swizzling.
*/
mutex_lock(&obj->mm.lock);
- if (obj->mm.pages &&
+ if (i915_gem_object_has_pages(obj) &&
obj->mm.madv == I915_MADV_WILLNEED &&
i915->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
if (tiling == I915_TILING_NONE) {
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 4d712a4db63b..9afeb68e2d44 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -82,7 +82,7 @@ static void cancel_userptr(struct work_struct *work)
/* We are inside a kthread context and can't be interrupted */
if (i915_gem_object_unbind(obj) == 0)
__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
- WARN_ONCE(obj->mm.pages,
+ WARN_ONCE(i915_gem_object_has_pages(obj),
"Failed to release pages: bind_count=%d, pages_pin_count=%d, pin_display=%d\n",
obj->bind_count,
atomic_read(&obj->mm.pages_pin_count),