Start exercising the scattergather lists, especially looking at
iteration after coalescing.
v2: Comment on the peculiarity of table construction (i.e. why this
sg_table might be interesting).
v3: Added one __func__ to identify expect_pfn_sg()
v4: Loop until we have crossed the chain boundary (forcing sg_table to
do multiple allocations) before squelching a potential ENOMEM from oom.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem.c | 11 +-
.../gpu/drm/i915/selftests/i915_mock_selftests.h | 1 +
drivers/gpu/drm/i915/selftests/scatterlist.c | 355 +++++++++++++++++++++
3 files changed, 364 insertions(+), 3 deletions(-)
create mode 100644 drivers/gpu/drm/i915/selftests/scatterlist.c
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 638b335e72b6..c91e5d10cc58 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2224,17 +2224,17 @@ void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
mutex_unlock(&obj->mm.lock);
}
-static void i915_sg_trim(struct sg_table *orig_st)
+static bool i915_sg_trim(struct sg_table *orig_st)
{
struct sg_table new_st;
struct scatterlist *sg, *new_sg;
unsigned int i;
if (orig_st->nents == orig_st->orig_nents)
- return;
+ return false;
if (sg_alloc_table(&new_st, orig_st->nents, GFP_KERNEL | __GFP_NOWARN))
- return;
+ return false;
new_sg = new_st.sgl;
for_each_sg(orig_st->sgl, sg, orig_st->nents, i) {
@@ -2247,6 +2247,7 @@ static void i915_sg_trim(struct sg_table *orig_st)
sg_free_table(orig_st);
*orig_st = new_st;
+ return true;
}
static struct sg_table *
@@ -5019,3 +5020,7 @@ i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj,
sg = i915_gem_object_get_sg(obj, n, &offset);
return sg_dma_address(sg) + (offset << PAGE_SHIFT);
}
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftests/scatterlist.c"
+#endif
diff --git a/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h b/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h
index 69e97a2ba4a6..5f0bdda42ed8 100644
--- a/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h
+++ b/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h
@@ -9,3 +9,4 @@
* Tests are executed in order by igt/drv_selftest
*/
selftest(sanitycheck, i915_mock_sanitycheck) /* keep first (igt selfcheck) */
+selftest(scatterlist, scatterlist_mock_selftests)
diff --git a/drivers/gpu/drm/i915/selftests/scatterlist.c b/drivers/gpu/drm/i915/selftests/scatterlist.c
new file mode 100644
index 000000000000..eb2cda8e2b9f
--- /dev/null
+++ b/drivers/gpu/drm/i915/selftests/scatterlist.c
@@ -0,0 +1,355 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/prime_numbers.h>
+#include <linux/random.h>
+
+#include "../i915_selftest.h"
+
+#define PFN_BIAS (1 << 10)
+
+struct pfn_table {
+ struct sg_table st;
+ unsigned long start, end;
+};
+
+typedef unsigned int (*npages_fn_t)(unsigned long n,
+ unsigned long count,
+ struct rnd_state *rnd);
+
+static noinline int expect_pfn_sg(struct pfn_table *pt,
+ npages_fn_t npages_fn,
+ struct rnd_state *rnd,
+ const char *who,
+ unsigned long timeout)
+{
+ struct scatterlist *sg;
+ unsigned long pfn, n;
+
+ pfn = pt->start;
+ for_each_sg(pt->st.sgl, sg, pt->st.nents, n) {
+ struct page *page = sg_page(sg);
+ unsigned int npages = npages_fn(n, pt->st.nents, rnd);
+
+ if (page_to_pfn(page) != pfn) {
+ pr_err("%s: %s left pages out of order, expected pfn %lu, found pfn %lu (using for_each_sg)\n",
+ __func__, who, pfn, page_to_pfn(page));
+ return -EINVAL;
+ }
+
+ if (sg->length != npages * PAGE_SIZE) {
+ pr_err("%s: %s copied wrong sg length, expected size %lu, found %u (using for_each_sg)\n",
+ __func__, who, npages * PAGE_SIZE, sg->length);
+ return -EINVAL;
+ }
+
+ if (igt_timeout(timeout, "%s timed out\n", who))
+ return -EINTR;
+
+ pfn += npages;
+ }
+ if (pfn != pt->end) {
+ pr_err("%s: %s finished on wrong pfn, expected %lu, found %lu\n",
+ __func__, who, pt->end, pfn);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static noinline int expect_pfn_sg_page_iter(struct pfn_table *pt,
+ const char *who,
+ unsigned long timeout)
+{
+ struct sg_page_iter sgiter;
+ unsigned long pfn;
+
+ pfn = pt->start;
+ for_each_sg_page(pt->st.sgl, &sgiter, pt->st.nents, 0) {
+ struct page *page = sg_page_iter_page(&sgiter);
+
+ if (page != pfn_to_page(pfn)) {
+ pr_err("%s: %s left pages out of order, expected pfn %lu, found pfn %lu (using for_each_sg_page)\n",
+ __func__, who, pfn, page_to_pfn(page));
+ return -EINVAL;
+ }
+
+ if (igt_timeout(timeout, "%s timed out\n", who))
+ return -EINTR;
+
+ pfn++;
+ }
+ if (pfn != pt->end) {
+ pr_err("%s: %s finished on wrong pfn, expected %lu, found %lu\n",
+ __func__, who, pt->end, pfn);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static noinline int expect_pfn_sgtiter(struct pfn_table *pt,
+ const char *who,
+ unsigned long timeout)
+{
+ struct sgt_iter sgt;
+ struct page *page;
+ unsigned long pfn;
+
+ pfn = pt->start;
+ for_each_sgt_page(page, sgt, &pt->st) {
+ if (page != pfn_to_page(pfn)) {
+ pr_err("%s: %s left pages out of order, expected pfn %lu, found pfn %lu (using for_each_sgt_page)\n",
+ __func__, who, pfn, page_to_pfn(page));
+ return -EINVAL;
+ }
+
+ if (igt_timeout(timeout, "%s timed out\n", who))
+ return -EINTR;
+
+ pfn++;
+ }
+ if (pfn != pt->end) {
+ pr_err("%s: %s finished on wrong pfn, expected %lu, found %lu\n",
+ __func__, who, pt->end, pfn);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int expect_pfn_sgtable(struct pfn_table *pt,
+ npages_fn_t npages_fn,
+ struct rnd_state *rnd,
+ const char *who,
+ unsigned long timeout)
+{
+ int err;
+
+ err = expect_pfn_sg(pt, npages_fn, rnd, who, timeout);
+ if (err)
+ return err;
+
+ err = expect_pfn_sg_page_iter(pt, who, timeout);
+ if (err)
+ return err;
+
+ err = expect_pfn_sgtiter(pt, who, timeout);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static unsigned int one(unsigned long n,
+ unsigned long count,
+ struct rnd_state *rnd)
+{
+ return 1;
+}
+
+static unsigned int grow(unsigned long n,
+ unsigned long count,
+ struct rnd_state *rnd)
+{
+ return n + 1;
+}
+
+static unsigned int shrink(unsigned long n,
+ unsigned long count,
+ struct rnd_state *rnd)
+{
+ return count - n;
+}
+
+static unsigned int random(unsigned long n,
+ unsigned long count,
+ struct rnd_state *rnd)
+{
+ return 1 + (prandom_u32_state(rnd) % 1024);
+}
+
+static int alloc_table(struct pfn_table *pt,
+ unsigned long count, unsigned long max,
+ npages_fn_t npages_fn,
+ struct rnd_state *rnd,
+ int alloc_error)
+{
+ struct scatterlist *sg;
+ unsigned long n, pfn;
+
+ if (sg_alloc_table(&pt->st, max,
+ GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN))
+ return alloc_error;
+
+ /* count should be less than 20 to prevent overflowing sg->length */
+ GEM_BUG_ON(overflows_type(count * PAGE_SIZE, sg->length));
+
+ /* Construct a table where each scatterlist contains different number
+ * of entries. The idea is to check that we can iterate the individual
+ * pages from inside the coalesced lists.
+ */
+ pt->start = PFN_BIAS;
+ pfn = pt->start;
+ sg = pt->st.sgl;
+ for (n = 0; n < count; n++) {
+ unsigned long npages = npages_fn(n, count, rnd);
+
+ /* Nobody expects the Sparse Memmap! */
+ if (pfn_to_page(pfn + npages) != pfn_to_page(pfn) + npages) {
+ sg_free_table(&pt->st);
+ return -ENOSPC;
+ }
+
+ if (n)
+ sg = sg_next(sg);
+ sg_set_page(sg, pfn_to_page(pfn), npages * PAGE_SIZE, 0);
+
+ GEM_BUG_ON(page_to_pfn(sg_page(sg)) != pfn);
+ GEM_BUG_ON(sg->length != npages * PAGE_SIZE);
+ GEM_BUG_ON(sg->offset != 0);
+
+ pfn += npages;
+ }
+ sg_mark_end(sg);
+ pt->st.nents = n;
+ pt->end = pfn;
+
+ return 0;
+}
+
+static const npages_fn_t npages_funcs[] = {
+ one,
+ grow,
+ shrink,
+ random,
+ NULL,
+};
+
+static int igt_sg_alloc(void *ignored)
+{
+ IGT_TIMEOUT(end_time);
+ const unsigned long max_order = 20; /* approximating a 4GiB object */
+ struct rnd_state prng;
+ unsigned long prime;
+ int alloc_error = -ENOMEM;
+
+ for_each_prime_number(prime, max_order) {
+ unsigned long size = BIT(prime);
+ int offset;
+
+ for (offset = -1; offset <= 1; offset++) {
+ unsigned long sz = size + offset;
+ const npages_fn_t *npages;
+ struct pfn_table pt;
+ int err;
+
+ for (npages = npages_funcs; *npages; npages++) {
+ prandom_seed_state(&prng,
+ i915_selftest.random_seed);
+ err = alloc_table(&pt, sz, sz, *npages, &prng,
+ alloc_error);
+ if (err == -ENOSPC)
+ break;
+ if (err)
+ return err;
+
+ prandom_seed_state(&prng,
+ i915_selftest.random_seed);
+ err = expect_pfn_sgtable(&pt, *npages, &prng,
+ "sg_alloc_table",
+ end_time);
+ sg_free_table(&pt.st);
+ if (err)
+ return err;
+ }
+ }
+
+ /* Test at least one continuation before accepting oom */
+ if (size > SG_MAX_SINGLE_ALLOC)
+ alloc_error = -ENOSPC;
+ }
+
+ return 0;
+}
+
+static int igt_sg_trim(void *ignored)
+{
+ IGT_TIMEOUT(end_time);
+ const unsigned long max = PAGE_SIZE; /* not prime! */
+ struct pfn_table pt;
+ unsigned long prime;
+ int alloc_error = -ENOMEM;
+
+ for_each_prime_number(prime, max) {
+ const npages_fn_t *npages;
+ int err;
+
+ for (npages = npages_funcs; *npages; npages++) {
+ struct rnd_state prng;
+
+ prandom_seed_state(&prng, i915_selftest.random_seed);
+ err = alloc_table(&pt, prime, max, *npages, &prng,
+ alloc_error);
+ if (err == -ENOSPC)
+ break;
+ if (err)
+ return err;
+
+ if (i915_sg_trim(&pt.st)) {
+ if (pt.st.orig_nents != prime ||
+ pt.st.nents != prime) {
+ pr_err("i915_sg_trim failed (nents %u, orig_nents %u), expected %lu\n",
+ pt.st.nents, pt.st.orig_nents, prime);
+ err = -EINVAL;
+ } else {
+ prandom_seed_state(&prng,
+ i915_selftest.random_seed);
+ err = expect_pfn_sgtable(&pt,
+ *npages, &prng,
+ "i915_sg_trim",
+ end_time);
+ }
+ }
+ sg_free_table(&pt.st);
+ if (err)
+ return err;
+ }
+
+ /* Test at least one continuation before accepting oom */
+ if (prime > SG_MAX_SINGLE_ALLOC)
+ alloc_error = -ENOSPC;
+ }
+
+ return 0;
+}
+
+int scatterlist_mock_selftests(void)
+{
+ static const struct i915_subtest tests[] = {
+ SUBTEST(igt_sg_alloc),
+ SUBTEST(igt_sg_trim),
+ };
+
+ return i915_subtests(tests, NULL);
+}
--
2.11.0
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