drm/i915: eliminate 'temp' in gen8_for_each_{pdd, pdpe, pml4e} macros

All of these iterator macros require a 'temp' argument, used merely to
hold internal partial results. We can instead declare the temporary
variable inside the macro, so the caller need not provide it.

Some of the old code contained nested iterators that actually reused the
same 'temp' variable for both inner and outer instances. It's quite
surprising that this didn't introduce bugs! But it does show that the
value of 'temp' isn't required to persist during the iterated body.

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449581451-11848-2-git-send-email-david.s.gordon@intel.com

2 files changed, 41 insertions, 47 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 1f7e6b9df45d..c25e8b017875 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -770,10 +770,10 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
 		gen8_ppgtt_clear_pte_range(vm, &ppgtt->pdp, start, length,
 					   scratch_pte);
 	} else {
-		uint64_t templ4, pml4e;
+		uint64_t pml4e;
 		struct i915_page_directory_pointer *pdp;
 
-		gen8_for_each_pml4e(pdp, &ppgtt->pml4, start, length, templ4, pml4e) {
+		gen8_for_each_pml4e(pdp, &ppgtt->pml4, start, length, pml4e) {
 			gen8_ppgtt_clear_pte_range(vm, pdp, start, length,
 						   scratch_pte);
 		}
@@ -839,10 +839,10 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
 					      cache_level);
 	} else {
 		struct i915_page_directory_pointer *pdp;
-		uint64_t templ4, pml4e;
+		uint64_t pml4e;
 		uint64_t length = (uint64_t)pages->orig_nents << PAGE_SHIFT;
 
-		gen8_for_each_pml4e(pdp, &ppgtt->pml4, start, length, templ4, pml4e) {
+		gen8_for_each_pml4e(pdp, &ppgtt->pml4, start, length, pml4e) {
 			gen8_ppgtt_insert_pte_entries(vm, pdp, &sg_iter,
 						      start, cache_level);
 		}
@@ -1020,10 +1020,9 @@ static int gen8_ppgtt_alloc_pagetabs(struct i915_address_space *vm,
 {
 	struct drm_device *dev = vm->dev;
 	struct i915_page_table *pt;
-	uint64_t temp;
 	uint32_t pde;
 
-	gen8_for_each_pde(pt, pd, start, length, temp, pde) {
+	gen8_for_each_pde(pt, pd, start, length, pde) {
 		/* Don't reallocate page tables */
 		if (test_bit(pde, pd->used_pdes)) {
 			/* Scratch is never allocated this way */
@@ -1082,13 +1081,12 @@ gen8_ppgtt_alloc_page_directories(struct i915_address_space *vm,
 {
 	struct drm_device *dev = vm->dev;
 	struct i915_page_directory *pd;
-	uint64_t temp;
 	uint32_t pdpe;
 	uint32_t pdpes = I915_PDPES_PER_PDP(dev);
 
 	WARN_ON(!bitmap_empty(new_pds, pdpes));
 
-	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
+	gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
 		if (test_bit(pdpe, pdp->used_pdpes))
 			continue;
 
@@ -1136,12 +1134,11 @@ gen8_ppgtt_alloc_page_dirpointers(struct i915_address_space *vm,
 {
 	struct drm_device *dev = vm->dev;
 	struct i915_page_directory_pointer *pdp;
-	uint64_t temp;
 	uint32_t pml4e;
 
 	WARN_ON(!bitmap_empty(new_pdps, GEN8_PML4ES_PER_PML4));
 
-	gen8_for_each_pml4e(pdp, pml4, start, length, temp, pml4e) {
+	gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
 		if (!test_bit(pml4e, pml4->used_pml4es)) {
 			pdp = alloc_pdp(dev);
 			if (IS_ERR(pdp))
@@ -1225,7 +1222,6 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
 	struct i915_page_directory *pd;
 	const uint64_t orig_start = start;
 	const uint64_t orig_length = length;
-	uint64_t temp;
 	uint32_t pdpe;
 	uint32_t pdpes = I915_PDPES_PER_PDP(dev);
 	int ret;
@@ -1252,7 +1248,7 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
 	}
 
 	/* For every page directory referenced, allocate page tables */
-	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
+	gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
 		ret = gen8_ppgtt_alloc_pagetabs(vm, pd, start, length,
 						new_page_tables + pdpe * BITS_TO_LONGS(I915_PDES));
 		if (ret)
@@ -1264,7 +1260,7 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
 
 	/* Allocations have completed successfully, so set the bitmaps, and do
 	 * the mappings. */
-	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
+	gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
 		gen8_pde_t *const page_directory = kmap_px(pd);
 		struct i915_page_table *pt;
 		uint64_t pd_len = length;
@@ -1274,7 +1270,7 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
 		/* Every pd should be allocated, we just did that above. */
 		WARN_ON(!pd);
 
-		gen8_for_each_pde(pt, pd, pd_start, pd_len, temp, pde) {
+		gen8_for_each_pde(pt, pd, pd_start, pd_len, pde) {
 			/* Same reasoning as pd */
 			WARN_ON(!pt);
 			WARN_ON(!pd_len);
@@ -1311,6 +1307,8 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
 
 err_out:
 	while (pdpe--) {
+		unsigned long temp;
+
 		for_each_set_bit(temp, new_page_tables + pdpe *
 				BITS_TO_LONGS(I915_PDES), I915_PDES)
 			free_pt(dev, pdp->page_directory[pdpe]->page_table[temp]);
@@ -1333,7 +1331,7 @@ static int gen8_alloc_va_range_4lvl(struct i915_address_space *vm,
 	struct i915_hw_ppgtt *ppgtt =
 			container_of(vm, struct i915_hw_ppgtt, base);
 	struct i915_page_directory_pointer *pdp;
-	uint64_t temp, pml4e;
+	uint64_t pml4e;
 	int ret = 0;
 
 	/* Do the pml4 allocations first, so we don't need to track the newly
@@ -1352,7 +1350,7 @@ static int gen8_alloc_va_range_4lvl(struct i915_address_space *vm,
 	     "The allocation has spanned more than 512GB. "
 	     "It is highly likely this is incorrect.");
 
-	gen8_for_each_pml4e(pdp, pml4, start, length, temp, pml4e) {
+	gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
 		WARN_ON(!pdp);
 
 		ret = gen8_alloc_va_range_3lvl(vm, pdp, start, length);
@@ -1392,10 +1390,9 @@ static void gen8_dump_pdp(struct i915_page_directory_pointer *pdp,
 			  struct seq_file *m)
 {
 	struct i915_page_directory *pd;
-	uint64_t temp;
 	uint32_t pdpe;
 
-	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
+	gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
 		struct i915_page_table *pt;
 		uint64_t pd_len = length;
 		uint64_t pd_start = start;
@@ -1405,7 +1402,7 @@ static void gen8_dump_pdp(struct i915_page_directory_pointer *pdp,
 			continue;
 
 		seq_printf(m, "\tPDPE #%d\n", pdpe);
-		gen8_for_each_pde(pt, pd, pd_start, pd_len, temp, pde) {
+		gen8_for_each_pde(pt, pd, pd_start, pd_len, pde) {
 			uint32_t  pte;
 			gen8_pte_t *pt_vaddr;
 
@@ -1455,11 +1452,11 @@ static void gen8_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
 	if (!USES_FULL_48BIT_PPGTT(vm->dev)) {
 		gen8_dump_pdp(&ppgtt->pdp, start, length, scratch_pte, m);
 	} else {
-		uint64_t templ4, pml4e;
+		uint64_t pml4e;
 		struct i915_pml4 *pml4 = &ppgtt->pml4;
 		struct i915_page_directory_pointer *pdp;
 
-		gen8_for_each_pml4e(pdp, pml4, start, length, templ4, pml4e) {
+		gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
 			if (!test_bit(pml4e, pml4->used_pml4es))
 				continue;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 877c32c78a6a..b448ad832dcf 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -455,32 +455,29 @@ static inline uint32_t gen6_pde_index(uint32_t addr)
  * between from start until start + length. On gen8+ it simply iterates
  * over every page directory entry in a page directory.
  */
-#define gen8_for_each_pde(pt, pd, start, length, temp, iter)		\
-	for (iter = gen8_pde_index(start); \
-	     length > 0 && iter < I915_PDES ? \
-			(pt = (pd)->page_table[iter]), 1 : 0; \
-	     iter++,				\
-	     temp = ALIGN(start+1, 1 << GEN8_PDE_SHIFT) - start,	\
-	     temp = min(temp, length),					\
-	     start += temp, length -= temp)
-
-#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter)	\
-	for (iter = gen8_pdpe_index(start); \
-	     length > 0 && (iter < I915_PDPES_PER_PDP(dev)) ? \
-			(pd = (pdp)->page_directory[iter]), 1 : 0; \
-	     iter++,				\
-	     temp = ALIGN(start+1, 1 << GEN8_PDPE_SHIFT) - start,	\
-	     temp = min(temp, length),					\
-	     start += temp, length -= temp)
-
-#define gen8_for_each_pml4e(pdp, pml4, start, length, temp, iter)	\
-	for (iter = gen8_pml4e_index(start);	\
-	     length > 0 && iter < GEN8_PML4ES_PER_PML4 ? \
-			(pdp = (pml4)->pdps[iter]), 1 : 0; \
-	     iter++,				\
-	     temp = ALIGN(start+1, 1ULL << GEN8_PML4E_SHIFT) - start,	\
-	     temp = min(temp, length),					\
-	     start += temp, length -= temp)
+#define gen8_for_each_pde(pt, pd, start, length, iter)			\
+	for (iter = gen8_pde_index(start);				\
+	     length > 0 && iter < I915_PDES &&				\
+		(pt = (pd)->page_table[iter], true);			\
+	     ({ u64 temp = ALIGN(start+1, 1 << GEN8_PDE_SHIFT);		\
+		    temp = min(temp - start, length);			\
+		    start += temp, length -= temp; }), ++iter)
+
+#define gen8_for_each_pdpe(pd, pdp, start, length, iter)		\
+	for (iter = gen8_pdpe_index(start);				\
+	     length > 0 && iter < I915_PDPES_PER_PDP(dev) &&		\
+		(pd = (pdp)->page_directory[iter], true);		\
+	     ({ u64 temp = ALIGN(start+1, 1 << GEN8_PDPE_SHIFT);	\
+		    temp = min(temp - start, length);			\
+		    start += temp, length -= temp; }), ++iter)
+
+#define gen8_for_each_pml4e(pdp, pml4, start, length, iter)		\
+	for (iter = gen8_pml4e_index(start);				\
+	     length > 0 && iter < GEN8_PML4ES_PER_PML4 &&		\
+		(pdp = (pml4)->pdps[iter], true);			\
+	     ({ u64 temp = ALIGN(start+1, 1ULL << GEN8_PML4E_SHIFT);	\
+		    temp = min(temp - start, length);			\
+		    start += temp, length -= temp; }), ++iter)
 
 static inline uint32_t gen8_pte_index(uint64_t address)
 {