Re: [Linaro-mm-sig] [PATCH 03/28] dma-buf: add dma_resv selftest

On 01/10/2021 11:05, Christian König wrote:

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

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 | 164 ++++++++++++++++++++++++++++++++++ 3 files changed, 167 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..ea44769d058d --- /dev/null +++ b/drivers/dma-buf/st-dma-resv.c @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: MIT */

+/* +* Copyright © 2019 Intel Corporation +*/

May want to update the year.

+//#include <linux/delay.h> +//#include <linux/dma-fence.h> +//#include <linux/kernel.h> +//#include <linux/kthread.h> +//#include <linux/sched/signal.h>

And remove these?

+#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_fence *f;
• f = alloc_fence();
• if (!f)

• return -ENOMEM;
  

• dma_fence_signal(f);
• dma_fence_put(f);
• return 0;

+}

+static int test_excl_signaling(void *arg) +{

• struct dma_resv resv;
• struct dma_fence *f;
• int err = -EINVAL;
• f = alloc_fence();
• if (!f)

• return -ENOMEM;
  

• dma_resv_init(&resv);
• dma_resv_add_excl_fence(&resv, f);
• if (dma_resv_test_signaled(&resv, false)) {

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

• goto err_free;
  

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

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

• goto err_free;
  

• }
• err = 0;

+err_free:

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

+}

+static int test_shared_signaling(void *arg) +{

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

• return -ENOMEM;
  

• dma_resv_init(&resv);
• err = dma_resv_reserve_shared(&resv, 1);
• if (err) {

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

• goto err_free;
  

• }
• err = -EINVAL;
• dma_resv_add_shared_fence(&resv, f);
• if (dma_resv_test_signaled(&resv, true)) {

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

• goto err_free;
  

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

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

• goto err_free;
  

• }
• err = 0;

+err_free:

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

+}

Task for a rainy day - consolidate the above two into parameter driven dma_resv setup (more fences, mixed signaling status, mixed exclusive and shared, different signaling mode) and common verification stages.

+static int test_excl_for_each(void *arg) +{

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

• return -ENOMEM;
  

• dma_resv_init(&resv);
• dma_resv_add_excl_fence(&resv, f);
• err = -EINVAL;
• dma_resv_for_each_fence(&cursor, &resv, false, fence) {

What about the dma_resv_assert_held(cursor->obj) assert? I must be missing something..

• if (f != fence) {
  

• 	pr_err("Unexpected fence\n");
  

Best set err to something, unit tests should be super robust, like if unexpected fence follows the expected one.

• 	goto err_free;
  

• }
  

• err = 0;
  

• }
• if (err) {

• pr_err("No fence found\n");
  

• goto err_free;
  

• }
• dma_fence_signal(f);
• err = 0;

Looks like err is already zero here, courtesy of the above "if (err) goto".

+err_free:

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

+}

Similar coverage extensions on a rainy day for this one - I mean testing more than just a single excl fence.

+int dma_resv(void) +{

• static const struct subtest tests[] = {

• SUBTEST(sanitycheck),
  

• SUBTEST(test_excl_signaling),
  

• SUBTEST(test_shared_signaling),
  

• SUBTEST(test_excl_for_each),
  

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

+}

You acknowledge in the commit message coverage is poor but I have no complaints since it is better than nothing. Just a question on that assert and maybe some tidies.

Regards,

Tvrtko