Commit 4c5896dc authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Hold a reference to the active HW context 



For virtual engines, we need to keep the HW context alive while it
remains in use. For regular HW contexts, they are created and kept alive
until the end of the GEM context. For simplicity, generalise the
requirements and keep an active reference to each HW context.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190318212347.30146-2-chris@chris-wilson.co.uk
parent 206c2f81

drivers/gpu/drm/i915/i915_gem_context.c

+1 −1
Original line number Diff line number Diff line
@@ -232,7 +232,7 @@ static void i915_gem_context_free(struct i915_gem_context *ctx) 
	i915_ppgtt_put(ctx->ppgtt);



	rbtree_postorder_for_each_entry_safe(it, n, &ctx->hw_contexts, node)

		it->ops->destroy(it);

		intel_context_put(it);



	kfree(ctx->name);

	put_pid(ctx->pid);

drivers/gpu/drm/i915/intel_context.c

+6 −0
Original line number Diff line number Diff line
@@ -172,6 +172,7 @@ intel_context_pin(struct i915_gem_context *ctx, 
		list_add(&ce->active_link, &ctx->active_engines);

		mutex_unlock(&ctx->mutex);



		intel_context_get(ce);

		smp_mb__before_atomic(); /* flush pin before it is visible */

	}
@@ -192,6 +193,7 @@ void intel_context_unpin(struct intel_context *ce) 
		return;



	/* We may be called from inside intel_context_pin() to evict another */

	intel_context_get(ce);

	mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);



	if (likely(atomic_dec_and_test(&ce->pin_count))) {
@@ -202,9 +204,11 @@ void intel_context_unpin(struct intel_context *ce) 
		mutex_unlock(&ce->gem_context->mutex);



		i915_gem_context_put(ce->gem_context);

		intel_context_put(ce);

	}



	mutex_unlock(&ce->pin_mutex);

	intel_context_put(ce);

}



static void intel_context_retire(struct i915_active_request *active,
@@ -221,6 +225,8 @@ intel_context_init(struct intel_context *ce, 
		   struct i915_gem_context *ctx,

		   struct intel_engine_cs *engine)

{

	kref_init(&ce->ref);



	ce->gem_context = ctx;

	ce->engine = engine;

	ce->ops = engine->cops;

drivers/gpu/drm/i915/intel_context.h

+11 −0
Original line number Diff line number Diff line
@@ -73,4 +73,15 @@ static inline void __intel_context_pin(struct intel_context *ce) 


void intel_context_unpin(struct intel_context *ce);



static inline struct intel_context *intel_context_get(struct intel_context *ce)

{

	kref_get(&ce->ref);

	return ce;

}



static inline void intel_context_put(struct intel_context *ce)

{

	kref_put(&ce->ref, ce->ops->destroy);

}



#endif /* __INTEL_CONTEXT_H__ */

drivers/gpu/drm/i915/intel_context_types.h

+5 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#ifndef __INTEL_CONTEXT_TYPES__

#define __INTEL_CONTEXT_TYPES__



#include <linux/kref.h>

#include <linux/list.h>

#include <linux/mutex.h>

#include <linux/rbtree.h>
@@ -22,7 +23,8 @@ struct intel_ring; 
struct intel_context_ops {

	int (*pin)(struct intel_context *ce);

	void (*unpin)(struct intel_context *ce);

	void (*destroy)(struct intel_context *ce);



	void (*destroy)(struct kref *kref);

};



/*
@@ -36,6 +38,8 @@ struct intel_sseu { 
};



struct intel_context {

	struct kref ref;



	struct i915_gem_context *gem_context;

	struct intel_engine_cs *engine;

	struct intel_engine_cs *active;

drivers/gpu/drm/i915/intel_lrc.c

+3 −1
Original line number Diff line number Diff line
@@ -1236,8 +1236,10 @@ static void __execlists_context_fini(struct intel_context *ce) 
	i915_gem_object_put(ce->state->obj);

}



static void execlists_context_destroy(struct intel_context *ce)

static void execlists_context_destroy(struct kref *kref)

{

	struct intel_context *ce = container_of(kref, typeof(*ce), ref);



	GEM_BUG_ON(intel_context_is_pinned(ce));



	if (ce->state)

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