drm/i915/bdw: Kill ppgtt->num_pt_pages

With the original PPGTT implementation if the number of PDPs was not a
power of two, the number of pages for the page tables would end up being
rounded up. The code actually had a bug here afaict, but this is a
theoretical bug as I don't believe this can actually occur with the
current code/HW..

With the rework of the page table allocations, there is no longer a
distinction between number of page table pages, and number of page
directory entries. To avoid confusion, kill the redundant (and newer)
struct member.

Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1759,7 +1759,7 @@ static void gen8_ppgtt_info(struct seq_file *m, struct drm_device *dev)
 		return;
 
 	seq_printf(m, "Page directories: %d\n", ppgtt->num_pd_pages);
-	seq_printf(m, "Page tables: %d\n", ppgtt->num_pt_pages);
+	seq_printf(m, "Page tables: %d\n", ppgtt->num_pd_entries);
 	for_each_ring(ring, dev_priv, unused) {
 		seq_printf(m, "%s\n", ring->name);
 		for (i = 0; i < 4; i++) {

drivers/gpu/drm/i915/i915_drv.h

@@ -697,13 +697,12 @@ struct i915_hw_ppgtt {
 	struct kref ref;
 	struct drm_mm_node node;
 	unsigned num_pd_entries;
+	unsigned num_pd_pages; /* gen8+ */
 	union {
 		struct page **pt_pages;
 		struct page **gen8_pt_pages[GEN8_LEGACY_PDPS];
 	};
 	struct page *pd_pages;
-	int num_pd_pages;
-	int num_pt_pages;
 	union {
 		uint32_t pd_offset;
 		dma_addr_t pd_dma_addr[GEN8_LEGACY_PDPS];

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -433,7 +433,6 @@ static int gen8_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt,
 					   const int max_pdp)
 {
 	struct page **pt_pages[GEN8_LEGACY_PDPS];
-	const int num_pt_pages = GEN8_PDES_PER_PAGE * max_pdp;
 	int i, ret;
 
 	for (i = 0; i < max_pdp; i++) {
@@ -450,8 +449,6 @@ static int gen8_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt,
 	for (i = 0; i < max_pdp; i++)
 		ppgtt->gen8_pt_pages[i] = pt_pages[i];
 
-	ppgtt->num_pt_pages = 1 << get_order(num_pt_pages << PAGE_SHIFT);
-
 	return 0;
 
 unwind_out:
@@ -618,18 +615,15 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
 	ppgtt->base.insert_entries = gen8_ppgtt_insert_entries;
 	ppgtt->base.cleanup = gen8_ppgtt_cleanup;
 	ppgtt->base.start = 0;
-	ppgtt->base.total = ppgtt->num_pt_pages * GEN8_PTES_PER_PAGE * PAGE_SIZE;
+	ppgtt->base.total = ppgtt->num_pd_entries * GEN8_PTES_PER_PAGE * PAGE_SIZE;
 
-	ppgtt->base.clear_range(&ppgtt->base, 0,
-				ppgtt->num_pd_entries * GEN8_PTES_PER_PAGE * PAGE_SIZE,
-				true);
+	ppgtt->base.clear_range(&ppgtt->base, 0, ppgtt->base.total, true);
 
 	DRM_DEBUG_DRIVER("Allocated %d pages for page directories (%d wasted)\n",
 			 ppgtt->num_pd_pages, ppgtt->num_pd_pages - max_pdp);
 	DRM_DEBUG_DRIVER("Allocated %d pages for page tables (%lld wasted)\n",
-			 ppgtt->num_pt_pages,
-			 (ppgtt->num_pt_pages - min_pt_pages) +
-			 size % (1<<30));
+			 ppgtt->num_pd_entries,
+			 (ppgtt->num_pd_entries - min_pt_pages) + size % (1<<30));
 	return 0;
 
 bail: