On 2/21/22 22:02, Dmitry Osipenko wrote:
21.02.2022 15:06, Mikko Perttunen пишет:
On 2/19/22 20:35, Dmitry Osipenko wrote:
18.02.2022 14:39, Mikko Perttunen пишет:
+ if (context->memory_context &&
context->client->ops->get_streamid_offset) {
^^^
+ int offset =
context->client->ops->get_streamid_offset(context->client);
+
+ if (offset >= 0) {
+ job->context = context->memory_context;
+ job->engine_streamid_offset = offset;
+ host1x_context_get(job->context);
+ }
You should bump refcount unconditionally or you'll get refcnt underflow
on put, when offset < 0.
This refcount is intended to be dropped from 'release_job', where it's
dropped if job->context is set, which it is from this path.
+ }
+
/*
* job_data is now part of job reference counting, so don't
release
* it from here.
diff --git a/drivers/gpu/drm/tegra/uapi.c b/drivers/gpu/drm/tegra/uapi.c
index 9ab9179d2026..be33da54d12c 100644
--- a/drivers/gpu/drm/tegra/uapi.c
+++ b/drivers/gpu/drm/tegra/uapi.c
@@ -33,6 +33,9 @@ static void tegra_drm_channel_context_close(struct
tegra_drm_context *context)
struct tegra_drm_mapping *mapping;
unsigned long id;
+ if (context->memory_context)
+ host1x_context_put(context->memory_context);
The "if (context->memory_context &&
context->client->ops->get_streamid_offset)" above doesn't match the "if
(context->memory_context)". You'll get refcount underflow.
And this drop is for the refcount implicitly added when allocating the
memory context through host1x_context_alloc; so these two places should
be independent.
Please elaborate if I missed something.
You named context as memory_context and then have
context=context->memory_context. Please try to improve the variable
names, like drm_ctx->host1x_ctx for example.
I'm also not a big fan of the "if (ref) put(ref)" pattern. Won't be
better to move all the "if (!NULL)" checks inside of get()/put() and
make the invocations unconditional?
I agree that the naming here is confusing with different kinds of
contexts flying around, though I would prefer not to change the original
'struct tegra_drm_context *context' since it's used all around the code.
But I'll try to make it clearer.
Regarding moving NULL checks inside get/put, I personally dislike that
pattern (also with e.g. kfree) since when reading the code, it makes it
more difficult to see that the pointer can be NULL.
Mikko
