Re: [Linaro-mm-sig] [PATCH 2/2] dma-buf: add dma_resv selftest v3

On 06/10/2021 13:36, Christian König wrote:

Just exercising a very minor subset of the functionality, but already proven useful.

v2: add missing locking v3: some more cleanup and consolidation, add unlocked test as well

Signed-off-by: Christian König christian.koenig@amd.com

drivers/dma-buf/Makefile | 3 +- drivers/dma-buf/selftests.h | 1 + drivers/dma-buf/st-dma-resv.c | 282 ++++++++++++++++++++++++++++++++++ 3 files changed, 285 insertions(+), 1 deletion(-) create mode 100644 drivers/dma-buf/st-dma-resv.c

diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index 1ef021273a06..511805dbeb75 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o dmabuf_selftests-y := \ selftest.o \ st-dma-fence.o \

• st-dma-fence-chain.o

• st-dma-fence-chain.o \
• st-dma-resv.o

obj-$(CONFIG_DMABUF_SELFTESTS) += dmabuf_selftests.o diff --git a/drivers/dma-buf/selftests.h b/drivers/dma-buf/selftests.h index bc8cea67bf1e..97d73aaa31da 100644 --- a/drivers/dma-buf/selftests.h +++ b/drivers/dma-buf/selftests.h @@ -12,3 +12,4 @@ selftest(sanitycheck, __sanitycheck__) /* keep first (igt selfcheck) */ selftest(dma_fence, dma_fence) selftest(dma_fence_chain, dma_fence_chain) +selftest(dma_resv, dma_resv) diff --git a/drivers/dma-buf/st-dma-resv.c b/drivers/dma-buf/st-dma-resv.c new file mode 100644 index 000000000000..50d3791ccb8c --- /dev/null +++ b/drivers/dma-buf/st-dma-resv.c @@ -0,0 +1,282 @@ +/* SPDX-License-Identifier: MIT */

+/* +* Copyright © 2019 Intel Corporation +* Copyright © 2021 Advanced Micro Devices, Inc. +*/

+#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/dma-resv.h>

+#include "selftest.h"

+static struct spinlock fence_lock;

+static const char *fence_name(struct dma_fence *f) +{

• return "selftest";

+}

+static const struct dma_fence_ops fence_ops = {

• .get_driver_name = fence_name,
• .get_timeline_name = fence_name,

+};

+static struct dma_fence *alloc_fence(void) +{

• struct dma_fence *f;
• f = kmalloc(sizeof(*f), GFP_KERNEL);
• if (!f)

• return NULL;
  

• dma_fence_init(f, &fence_ops, &fence_lock, 0, 0);
• return f;

+}

+static int sanitycheck(void *arg) +{

• struct dma_resv resv;
• struct dma_fence *f;
• int r;
• f = alloc_fence();
• if (!f)

• return -ENOMEM;
  

• dma_fence_signal(f);
• dma_fence_put(f);
• dma_resv_init(&resv);
• r = dma_resv_lock(&resv, NULL);
• if (r)

• pr_err("Resv locking failed\n");
  

• else

• dma_resv_unlock(&resv);
  

• dma_resv_fini(&resv);
• return r;

+}

+static int test_signaling(void *arg, bool shared) +{

• struct dma_resv resv;
• struct dma_fence *f;
• int r;
• f = alloc_fence();
• if (!f)

• return -ENOMEM;
  

• dma_resv_init(&resv);
• r = dma_resv_lock(&resv, NULL);
• if (r) {

• pr_err("Resv locking failed\n");
  

• goto err_free;
  

• }
• if (shared) {

• r = dma_resv_reserve_shared(&resv, 1);
  

• if (r) {
  

• 	pr_err("Resv shared slot allocation failed\n");
  

• 	goto err_unlock;
  

• }
  

• dma_resv_add_shared_fence(&resv, f);
  

• } else {

• dma_resv_add_excl_fence(&resv, f);
  

• }
• if (dma_resv_test_signaled(&resv, shared)) {

• pr_err("Resv unexpectedly signaled\n");
  

• r = -EINVAL;
  

• goto err_unlock;
  

• }
• dma_fence_signal(f);
• if (!dma_resv_test_signaled(&resv, shared)) {

• pr_err("Resv not reporting signaled\n");
  

• r = -EINVAL;
  

• goto err_unlock;
  

• }

+err_unlock:

• dma_resv_unlock(&resv);

+err_free:

• dma_resv_fini(&resv);
• dma_fence_put(f);
• return r;

+}

+static int test_excl_signaling(void *arg) +{

• return test_signaling(arg, false);

+}

+static int test_shared_signaling(void *arg) +{

• return test_signaling(arg, true);

+}

+static int test_for_each(void *arg, bool shared) +{

• struct dma_resv_iter cursor;
• struct dma_fence *f, *fence;
• struct dma_resv resv;
• int r;
• f = alloc_fence();
• if (!f)

• return -ENOMEM;
  

• dma_resv_init(&resv);
• r = dma_resv_lock(&resv, NULL);
• if (r) {

• pr_err("Resv locking failed\n");
  

• goto err_free;
  

• }
• if (shared) {

• r = dma_resv_reserve_shared(&resv, 1);
  

• if (r) {
  

• 	pr_err("Resv shared slot allocation failed\n");
  

• 	goto err_unlock;
  

• }
  

• dma_resv_add_shared_fence(&resv, f);
  

• } else {

• dma_resv_add_excl_fence(&resv, f);
  

• }

This block repeates three times so could be consolidated but it doesn't matter hugely.

• r = -ENOENT;
• dma_resv_for_each_fence(&cursor, &resv, shared, fence) {

• if (!r) {
  

• 	pr_err("More than one fence found\n");
  

• 	r = -EINVAL;
  

• 	goto err_unlock;
  

• }
  

• if (f != fence) {
  

• 	pr_err("Unexpected fence\n");
  

• 	r = -EINVAL;
  

• 	goto err_unlock;
  

• }
  

• if (dma_resv_iter_is_exclusive(&cursor) != !shared) {
  

• 	pr_err("Unexpected fence usage\n");
  

• 	r = -EINVAL;
  

• 	goto err_unlock;
  

• }
  

• r = 0;
  

• }
• if (r) {

• pr_err("No fence found\n");
  

• goto err_unlock;
  

• }
• dma_fence_signal(f);

This would warn if the loop jumps to err_unlock but I guess there are bigger problems in that case.

+err_unlock:

• dma_resv_unlock(&resv);

+err_free:

• dma_resv_fini(&resv);
• dma_fence_put(f);
• return r;

+}

+static int test_excl_for_each(void *arg) +{

• return test_for_each(arg, false);

+}

+static int test_shared_for_each(void *arg) +{

• return test_for_each(arg, false);

true

With that:

Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com

Regards,

Tvrtko

+}

+static int test_for_each_unlocked(void *arg, bool shared) +{

• struct dma_resv_iter cursor;
• struct dma_fence *f, *fence;
• struct dma_resv resv;
• int r;
• f = alloc_fence();
• if (!f)

• return -ENOMEM;
  

• dma_resv_init(&resv);
• r = dma_resv_lock(&resv, NULL);
• if (r) {

• pr_err("Resv locking failed\n");
  

• goto err_free;
  

• }
• if (shared) {

• r = dma_resv_reserve_shared(&resv, 1);
  

• if (r) {
  

• 	pr_err("Resv shared slot allocation failed\n");
  

• 	dma_resv_unlock(&resv);
  

• 	goto err_free;
  

• }
  

• dma_resv_add_shared_fence(&resv, f);
  

• } else {

• dma_resv_add_excl_fence(&resv, f);
  

• }
• dma_resv_unlock(&resv);
• r = -ENOENT;
• dma_resv_iter_begin(&cursor, &resv, shared);
• dma_resv_for_each_fence_unlocked(&cursor, fence) {

• if (!r) {
  

• 	dma_resv_iter_end(&cursor);
  

• 	pr_err("More than one fence found\n");
  

• 	r = -EINVAL;
  

• 	goto err_free;
  

• }
  

• if (f != fence) {
  

• 	dma_resv_iter_end(&cursor);
  

• 	pr_err("Unexpected fence\n");
  

• 	r = -EINVAL;
  

• 	goto err_free;
  

• }
  

• if (dma_resv_iter_is_exclusive(&cursor) != !shared) {
  

• 	dma_resv_iter_end(&cursor);
  

• 	pr_err("Unexpected fence usage\n");
  

• 	r = -EINVAL;
  

• 	goto err_free;
  

• }
  

• r = 0;
  

• }
• dma_resv_iter_end(&cursor);
• if (r) {

• pr_err("No fence found\n");
  

• goto err_free;
  

• }
• dma_fence_signal(f);

+err_free:

• dma_resv_fini(&resv);
• dma_fence_put(f);
• return r;

+}

+static int test_excl_for_each_unlocked(void *arg) +{

• return test_for_each_unlocked(arg, false);

+}

+static int test_shared_for_each_unlocked(void *arg) +{

• return test_for_each_unlocked(arg, true);

+}

+int dma_resv(void) +{

• static const struct subtest tests[] = {

• SUBTEST(sanitycheck),
  

• SUBTEST(test_excl_signaling),
  

• SUBTEST(test_shared_signaling),
  

• SUBTEST(test_excl_for_each),
  

• SUBTEST(test_shared_for_each),
  

• SUBTEST(test_excl_for_each_unlocked),
  

• SUBTEST(test_shared_for_each_unlocked),
  

• };
• spin_lock_init(&fence_lock);
• return subtests(tests, NULL);

+}