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drm/i915: eliminate 'temp' in gen8_for_each_{pdd, pdpe, pml4e} macros
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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
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Dave Gordon authored and Daniel Vetter committed Dec 10, 2015
1 parent a25c9f0 commit e8ebd8e
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Showing 2 changed files with 41 additions and 47 deletions.
39 changes: 18 additions & 21 deletions drivers/gpu/drm/i915/i915_gem_gtt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}
Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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))
Expand Down Expand Up @@ -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;
Expand All @@ -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)
Expand All @@ -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;
Expand All @@ -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);
Expand Down Expand Up @@ -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]);
Expand All @@ -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
Expand All @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand Down Expand Up @@ -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;

Expand Down
49 changes: 23 additions & 26 deletions drivers/gpu/drm/i915/i915_gem_gtt.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand Down

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