drm/i915/gt: Allocate i915_fence_reg array

Since the number of fence regs can vary dramactically between platforms,
allocate the array on demand so we don't waste as much space.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200316113846.4974-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_ggtt.c

@@ -698,11 +698,13 @@ static void ggtt_cleanup_hw(struct i915_ggtt *ggtt)
  */
 void i915_ggtt_driver_release(struct drm_i915_private *i915)
 {
+	struct i915_ggtt *ggtt = &i915->ggtt;
 	struct pagevec *pvec;
 
-	fini_aliasing_ppgtt(&i915->ggtt);
+	fini_aliasing_ppgtt(ggtt);
 
-	ggtt_cleanup_hw(&i915->ggtt);
+	intel_ggtt_fini_fences(ggtt);
+	ggtt_cleanup_hw(ggtt);
 
 	pvec = &i915->mm.wc_stash.pvec;
 	if (pvec->nr) {

drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c

@@ -857,6 +857,11 @@ void intel_ggtt_init_fences(struct i915_ggtt *ggtt)
 	if (intel_vgpu_active(i915))
 		num_fences = intel_uncore_read(uncore,
 					       vgtif_reg(avail_rs.fence_num));
+	ggtt->fence_regs = kcalloc(num_fences,
+				   sizeof(*ggtt->fence_regs),
+				   GFP_KERNEL);
+	if (!ggtt->fence_regs)
+		num_fences = 0;
 
 	/* Initialize fence registers to zero */
 	for (i = 0; i < num_fences; i++) {
@@ -871,6 +876,11 @@ void intel_ggtt_init_fences(struct i915_ggtt *ggtt)
 	intel_ggtt_restore_fences(ggtt);
 }
 
+void intel_ggtt_fini_fences(struct i915_ggtt *ggtt)
+{
+	kfree(ggtt->fence_regs);
+}
+
 void intel_gt_init_swizzling(struct intel_gt *gt)
 {
 	struct drm_i915_private *i915 = gt->i915;

drivers/gpu/drm/i915/gt/intel_ggtt_fencing.h

@@ -64,6 +64,7 @@ void i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj,
 					 struct sg_table *pages);
 
 void intel_ggtt_init_fences(struct i915_ggtt *ggtt);
+void intel_ggtt_fini_fences(struct i915_ggtt *ggtt);
 
 void intel_gt_init_swizzling(struct intel_gt *gt);
 

drivers/gpu/drm/i915/gt/intel_gtt.h

@@ -26,7 +26,6 @@
 #include <drm/drm_mm.h>
 
 #include "gt/intel_reset.h"
-#include "gt/intel_ggtt_fencing.h"
 #include "i915_selftest.h"
 #include "i915_vma_types.h"
 
@@ -135,6 +134,8 @@ typedef u64 gen8_pte_t;
 #define GEN8_PDE_IPS_64K BIT(11)
 #define GEN8_PDE_PS_2M   BIT(7)
 
+struct i915_fence_reg;
+
 #define for_each_sgt_daddr(__dp, __iter, __sgt) \
 	__for_each_sgt_daddr(__dp, __iter, __sgt, I915_GTT_PAGE_SIZE)
 
@@ -333,7 +334,7 @@ struct i915_ggtt {
 	u32 pin_bias;
 
 	unsigned int num_fences;
-	struct i915_fence_reg fence_regs[I915_MAX_NUM_FENCES];
+	struct i915_fence_reg *fence_regs;
 	struct list_head fence_list;
 
 	/**

drivers/gpu/drm/i915/i915_vma.h

@@ -30,6 +30,7 @@
 
 #include <drm/drm_mm.h>
 
+#include "gt/intel_ggtt_fencing.h"
 #include "gem/i915_gem_object.h"
 
 #include "i915_gem_gtt.h"