[Intel-gfx] [RFCv2 03/19] drm/i915: Add some selftests for sg_table manipulation

Chris Wilson chris at chris-wilson.co.uk
Tue Dec 20 13:07:58 UTC 2016


Start exercising the scattergather lists, especially looking at
iteration after coalescing.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c                    |  11 +-
 .../gpu/drm/i915/selftests/i915_mock_selftests.h   |   1 +
 drivers/gpu/drm/i915/selftests/scatterlist.c       | 255 +++++++++++++++++++++
 3 files changed, 264 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 891e479dbf5d..4547d4cd2064 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2315,17 +2315,17 @@ static unsigned int swiotlb_max_size(void)
 #endif
 }
 
-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) {
@@ -2338,6 +2338,7 @@ 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 *
@@ -4972,3 +4973,7 @@ 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..8639bb8fd50d 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, mock_scatterlist_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..9bc3bc6dbc41
--- /dev/null
+++ b/drivers/gpu/drm/i915/selftests/scatterlist.c
@@ -0,0 +1,255 @@
+/*
+ * 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 "i915_selftest.h"
+
+#define PFN_BIAS (1 << 10)
+
+struct pfn_table {
+	struct sg_table st;
+	unsigned long start, end;
+};
+
+static noinline int expect_pfn_sg(struct pfn_table *pt, const char *who)
+{
+	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);
+
+		if (page_to_pfn(page) != pfn) {
+			pr_err("%s left pages out of order, expected pfn %lu, found pfn %lu (using for_each_sg)\n",
+			       who, pfn, page_to_pfn(page));
+			return -EINVAL;
+		}
+
+		if (sg->length != (n + 1) * PAGE_SIZE) {
+			pr_err("%s: %s copied wrong sg length, expected size %lu, found %u (using for_each_sg)\n",
+			       __func__, who, (n + 1) * PAGE_SIZE, sg->length);
+			return -EINVAL;
+		}
+
+		cond_resched();
+		if (signal_pending(current))
+			return -EINTR;
+
+		pfn += n + 1;
+	}
+	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)
+{
+	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;
+		}
+
+		cond_resched();
+		if (signal_pending(current))
+			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)
+{
+	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;
+		}
+
+		cond_resched();
+		if (signal_pending(current))
+			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, const char *who)
+{
+	int err;
+
+	err = expect_pfn_sg(pt, who);
+	if (err)
+		return err;
+
+	err = expect_pfn_sg_page_iter(pt, who);
+	if (err)
+		return err;
+
+	err = expect_pfn_sgtiter(pt, who);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static bool alloc_table(struct pfn_table *pt,
+			unsigned long count,
+			unsigned long max)
+{
+	struct scatterlist *sg;
+	unsigned long n, pfn;
+
+	if (sg_alloc_table(&pt->st, max,
+			   GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN))
+		return false;
+
+	pt->start = PFN_BIAS;
+	pfn = pt->start;
+	sg = pt->st.sgl;
+	for (n = 0; n < count; n++) {
+		if (n)
+			sg = sg_next(sg);
+		sg_set_page(sg, pfn_to_page(pfn), (n + 1)*PAGE_SIZE, 0);
+		pfn += n + 1;
+	}
+	sg_mark_end(sg);
+	pt->st.nents = n;
+	pt->end = pfn;
+
+	return true;
+}
+
+static int igt_sg_alloc(void *ignored)
+{
+	I915_SELFTEST_TIMEOUT(end_time);
+	const unsigned long max_order = 20; /* approximating a 4GiB object */
+	unsigned long prime;
+
+	for_each_prime_number(prime, max_order) {
+		unsigned long size = BIT(prime);
+		int offset;
+
+		for (offset = -1; offset <= 1; offset++) {
+			struct pfn_table pt;
+			int err;
+
+			if (!alloc_table(&pt, size + offset, size + offset))
+				return 0; /* out of memory, give up */
+
+			err = expect_pfn_sgtable(&pt, "sg_alloc_table");
+			sg_free_table(&pt.st);
+			if (err)
+				return err;
+
+			if (time_after(jiffies, end_time)) {
+				pr_warn("%s timed out: last table size %lu\n",
+					__func__, size + offset);
+				return 0;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int igt_sg_trim(void *ignored)
+{
+	I915_SELFTEST_TIMEOUT(end_time);
+	const unsigned long max = PAGE_SIZE; /* not prime! */
+	struct pfn_table pt;
+	unsigned long prime;
+
+	for_each_prime_number(prime, max) {
+		int err;
+
+		if (!alloc_table(&pt, prime, max))
+			return 0; /* out of memory, give up */
+
+		err = 0;
+		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 {
+				err = expect_pfn_sgtable(&pt, "i915_sg_trim");
+			}
+		}
+		sg_free_table(&pt.st);
+		if (err)
+			return err;
+
+		if (time_after(jiffies, end_time)) {
+			pr_warn("%s timed out: last trim size %lu/%lu\n",
+				__func__, prime, max);
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+int mock_scatterlist_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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