drm/i915: add dev_priv->mm.stolen_lock

Which should protect dev_priv->mm.stolen usage. This will allow us to
simplify the relationship between stolen memory, FBC and struct_mutex.

v2:
  - Rebase after the stolen_remove_node() dev_priv patch move.
  - I realized that after we fixed a few things related to the FBC CFB
    size checks, we're not reallocating the CFB anymore with FBC
    enabled, so we can just move all the locking to i915_gem_stolen.c
    and stop worrying about freezing all the stolen alocations while
    freeing/rellocating the CFB. This allows us to fix the "Too
    coarse" observation from Chris.

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2b78686e23d9213ed4e67b440b98c2661484dddf..eb10c16240067ce273bfb5ef829b067093d5f1a2 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1245,6 +1245,10 @@ struct intel_l3_parity {
 struct i915_gem_mm {
        /** Memory allocator for GTT stolen memory */
        struct drm_mm stolen;
+       /** Protects the usage of the GTT stolen memory allocator. This is
+        * always the inner lock when overlapping with struct_mutex. */
+       struct mutex stolen_lock;
+
        /** List of all objects in gtt_space. Used to restore gtt
         * mappings on resume */
        struct list_head bound_list;

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index d2d556c69175590787433075ddacbd36ab369686..de76d886cd1d479a37ea47a79251367c366b9ac3 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -46,17 +46,25 @@ int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv,
                                struct drm_mm_node *node, u64 size,
                                unsigned alignment)
 {
+       int ret;
+
        if (!drm_mm_initialized(&dev_priv->mm.stolen))
                return -ENODEV;
 
-       return drm_mm_insert_node(&dev_priv->mm.stolen, node, size, alignment,
-                                 DRM_MM_SEARCH_DEFAULT);
+       mutex_lock(&dev_priv->mm.stolen_lock);
+       ret = drm_mm_insert_node(&dev_priv->mm.stolen, node, size, alignment,
+                                DRM_MM_SEARCH_DEFAULT);
+       mutex_unlock(&dev_priv->mm.stolen_lock);
+
+       return ret;
 }
 
 void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
                                 struct drm_mm_node *node)
 {
+       mutex_lock(&dev_priv->mm.stolen_lock);
        drm_mm_remove_node(node);
+       mutex_unlock(&dev_priv->mm.stolen_lock);
 }
 
 static unsigned long i915_stolen_to_physical(struct drm_device *dev)
@@ -184,6 +192,8 @@ int i915_gem_init_stolen(struct drm_device *dev)
        u32 tmp;
        int bios_reserved = 0;
 
+       mutex_init(&dev_priv->mm.stolen_lock);
+
 #ifdef CONFIG_INTEL_IOMMU
        if (intel_iommu_gfx_mapped && INTEL_INFO(dev)->gen < 8) {
                DRM_INFO("DMAR active, disabling use of stolen memory\n");
@@ -384,7 +394,9 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 
        stolen->start = stolen_offset;
        stolen->size = size;
+       mutex_lock(&dev_priv->mm.stolen_lock);
        ret = drm_mm_reserve_node(&dev_priv->mm.stolen, stolen);
+       mutex_unlock(&dev_priv->mm.stolen_lock);
        if (ret) {
                DRM_DEBUG_KMS("failed to allocate stolen space\n");
                kfree(stolen);