[PATCH] fixup! drm/msm: Separate locking of buffer resources from struct_mutex
Rob Clark
robdclark at gmail.com
Fri Jun 16 14:22:07 UTC 2017
---
Ok, 2nd fixup to handle vmap shrinking.
drivers/gpu/drm/msm/msm_gem.c | 44 +++++++++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index f5d1f84..3190e05 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -42,6 +42,9 @@ enum {
OBJ_LOCK_SHRINKER,
};
+static void msm_gem_vunmap_locked(struct drm_gem_object *obj);
+
+
static dma_addr_t physaddr(struct drm_gem_object *obj)
{
struct msm_gem_object *msm_obj = to_msm_bo(obj);
@@ -484,6 +487,7 @@ int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
void *msm_gem_get_vaddr(struct drm_gem_object *obj)
{
struct msm_gem_object *msm_obj = to_msm_bo(obj);
+ int ret = 0;
mutex_lock(&msm_obj->lock);
@@ -492,22 +496,35 @@ void *msm_gem_get_vaddr(struct drm_gem_object *obj)
return ERR_PTR(-EBUSY);
}
+ /* increment vmap_count *before* vmap() call, so shrinker can
+ * check vmap_count (is_vunmapable()) outside of msm_obj->lock.
+ * This guarantees that we won't try to msm_gem_vunmap() this
+ * same object from within the vmap() call (while we already
+ * hold msm_obj->lock)
+ */
+ msm_obj->vmap_count++;
+
if (!msm_obj->vaddr) {
struct page **pages = get_pages(obj);
if (IS_ERR(pages)) {
- mutex_unlock(&msm_obj->lock);
- return ERR_CAST(pages);
+ ret = PTR_ERR(pages);
+ goto fail;
}
msm_obj->vaddr = vmap(pages, obj->size >> PAGE_SHIFT,
VM_MAP, pgprot_writecombine(PAGE_KERNEL));
if (msm_obj->vaddr == NULL) {
- mutex_unlock(&msm_obj->lock);
- return ERR_PTR(-ENOMEM);
+ ret = -ENOMEM;
+ goto fail;
}
}
- msm_obj->vmap_count++;
+
mutex_unlock(&msm_obj->lock);
return msm_obj->vaddr;
+
+fail:
+ msm_obj->vmap_count--;
+ mutex_unlock(&msm_obj->lock);
+ return ERR_PTR(ret);
}
void msm_gem_put_vaddr(struct drm_gem_object *obj)
@@ -554,7 +571,7 @@ void msm_gem_purge(struct drm_gem_object *obj)
put_iova(obj);
- msm_gem_vunmap(obj);
+ msm_gem_vunmap_locked(obj);
put_pages(obj);
@@ -576,10 +593,12 @@ void msm_gem_purge(struct drm_gem_object *obj)
mutex_unlock(&msm_obj->lock);
}
-void msm_gem_vunmap(struct drm_gem_object *obj)
+static void msm_gem_vunmap_locked(struct drm_gem_object *obj)
{
struct msm_gem_object *msm_obj = to_msm_bo(obj);
+ WARN_ON(!mutex_is_locked(&msm_obj->lock));
+
if (!msm_obj->vaddr || WARN_ON(!is_vunmapable(msm_obj)))
return;
@@ -587,6 +606,15 @@ void msm_gem_vunmap(struct drm_gem_object *obj)
msm_obj->vaddr = NULL;
}
+void msm_gem_vunmap(struct drm_gem_object *obj)
+{
+ struct msm_gem_object *msm_obj = to_msm_bo(obj);
+
+ mutex_lock_nested(&msm_obj->lock, OBJ_LOCK_SHRINKER);
+ msm_gem_vunmap_locked(obj);
+ mutex_unlock(&msm_obj->lock);
+}
+
/* must be called before _move_to_active().. */
int msm_gem_sync_object(struct drm_gem_object *obj,
struct msm_fence_context *fctx, bool exclusive)
@@ -799,7 +827,7 @@ void msm_gem_free_object(struct drm_gem_object *obj)
drm_prime_gem_destroy(obj, msm_obj->sgt);
} else {
- msm_gem_vunmap(obj);
+ msm_gem_vunmap_locked(obj);
put_pages(obj);
}
--
2.9.4
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