drm/i915: Move context management under GEM

Keep track of the GEM contexts underneath i915->gem.contexts and assign
them their own lock for the purposes of list management.

v2: Focus on lock tracking; ctx->vm is protected by ctx->mutex
v3: Correct split with removal of logical HW ID

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-15-chris@chris-wilson.co.uk

5 files changed, 59 insertions, 42 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 35a40c2820a2..be34d97ac18f 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -221,12 +221,20 @@ intel_context_init(struct intel_context *ce,
 		   struct i915_gem_context *ctx,
 		   struct intel_engine_cs *engine)
 {
+	struct i915_address_space *vm;
+
 	GEM_BUG_ON(!engine->cops);
 
 	kref_init(&ce->ref);
 
 	ce->gem_context = ctx;
-	ce->vm = i915_vm_get(ctx->vm ?: &engine->gt->ggtt->vm);
+	rcu_read_lock();
+	vm = rcu_dereference(ctx->vm);
+	if (vm)
+		ce->vm = i915_vm_get(vm);
+	else
+		ce->vm = i915_vm_get(&engine->gt->ggtt->vm);
+	rcu_read_unlock();
 	if (ctx->timeline)
 		ce->timeline = intel_timeline_get(ctx->timeline);
 
diff --git a/drivers/gpu/drm/i915/gt/selftest_context.c b/drivers/gpu/drm/i915/gt/selftest_context.c
index 86cffbb0a9cb..7c838a57e174 100644
--- a/drivers/gpu/drm/i915/gt/selftest_context.c
+++ b/drivers/gpu/drm/i915/gt/selftest_context.c
@@ -155,13 +155,9 @@ static int live_context_size(void *arg)
 	 * HW tries to write past the end of one.
 	 */
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
-
 	fixme = kernel_context(gt->i915);
-	if (IS_ERR(fixme)) {
-		err = PTR_ERR(fixme);
-		goto unlock;
-	}
+	if (IS_ERR(fixme))
+		return PTR_ERR(fixme);
 
 	for_each_engine(engine, gt->i915, id) {
 		struct {
@@ -201,8 +197,6 @@ static int live_context_size(void *arg)
 	}
 
 	kernel_context_close(fixme);
-unlock:
-	mutex_unlock(&gt->i915->drm.struct_mutex);
 	return err;
 }
 
@@ -305,12 +299,10 @@ static int live_active_context(void *arg)
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
-
 	fixme = live_context(gt->i915, file);
 	if (IS_ERR(fixme)) {
 		err = PTR_ERR(fixme);
-		goto unlock;
+		goto out_file;
 	}
 
 	for_each_engine(engine, gt->i915, id) {
@@ -323,8 +315,7 @@ static int live_active_context(void *arg)
 			break;
 	}
 
-unlock:
-	mutex_unlock(&gt->i915->drm.struct_mutex);
+out_file:
 	mock_file_free(gt->i915, file);
 	return err;
 }
@@ -418,12 +409,10 @@ static int live_remote_context(void *arg)
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
-
 	fixme = live_context(gt->i915, file);
 	if (IS_ERR(fixme)) {
 		err = PTR_ERR(fixme);
-		goto unlock;
+		goto out_file;
 	}
 
 	for_each_engine(engine, gt->i915, id) {
@@ -436,8 +425,7 @@ static int live_remote_context(void *arg)
 			break;
 	}
 
-unlock:
-	mutex_unlock(&gt->i915->drm.struct_mutex);
+out_file:
 	mock_file_free(gt->i915, file);
 	return err;
 }
diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
index ffbb3d23b887..e8a40df79bd0 100644
--- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
+++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
@@ -58,9 +58,7 @@ static int hang_init(struct hang *h, struct intel_gt *gt)
 	memset(h, 0, sizeof(*h));
 	h->gt = gt;
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
 	h->ctx = kernel_context(gt->i915);
-	mutex_unlock(&gt->i915->drm.struct_mutex);
 	if (IS_ERR(h->ctx))
 		return PTR_ERR(h->ctx);
 
@@ -133,7 +131,7 @@ static struct i915_request *
 hang_create_request(struct hang *h, struct intel_engine_cs *engine)
 {
 	struct intel_gt *gt = h->gt;
-	struct i915_address_space *vm = h->ctx->vm ?: &engine->gt->ggtt->vm;
+	struct i915_address_space *vm = i915_gem_context_get_vm_rcu(h->ctx);
 	struct drm_i915_gem_object *obj;
 	struct i915_request *rq = NULL;
 	struct i915_vma *hws, *vma;
@@ -143,12 +141,15 @@ hang_create_request(struct hang *h, struct intel_engine_cs *engine)
 	int err;
 
 	obj = i915_gem_object_create_internal(gt->i915, PAGE_SIZE);
-	if (IS_ERR(obj))
+	if (IS_ERR(obj)) {
+		i915_vm_put(vm);
 		return ERR_CAST(obj);
+	}
 
 	vaddr = i915_gem_object_pin_map(obj, i915_coherent_map_type(gt->i915));
 	if (IS_ERR(vaddr)) {
 		i915_gem_object_put(obj);
+		i915_vm_put(vm);
 		return ERR_CAST(vaddr);
 	}
 
@@ -159,16 +160,22 @@ hang_create_request(struct hang *h, struct intel_engine_cs *engine)
 	h->batch = vaddr;
 
 	vma = i915_vma_instance(h->obj, vm, NULL);
-	if (IS_ERR(vma))
+	if (IS_ERR(vma)) {
+		i915_vm_put(vm);
 		return ERR_CAST(vma);
+	}
 
 	hws = i915_vma_instance(h->hws, vm, NULL);
-	if (IS_ERR(hws))
+	if (IS_ERR(hws)) {
+		i915_vm_put(vm);
 		return ERR_CAST(hws);
+	}
 
 	err = i915_vma_pin(vma, 0, 0, PIN_USER);
-	if (err)
+	if (err) {
+		i915_vm_put(vm);
 		return ERR_PTR(err);
+	}
 
 	err = i915_vma_pin(hws, 0, 0, PIN_USER);
 	if (err)
@@ -266,6 +273,7 @@ unpin_hws:
 	i915_vma_unpin(hws);
 unpin_vma:
 	i915_vma_unpin(vma);
+	i915_vm_put(vm);
 	return err ? ERR_PTR(err) : rq;
 }
 
@@ -382,9 +390,7 @@ static int igt_reset_nop(void *arg)
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
 	ctx = live_context(gt->i915, file);
-	mutex_unlock(&gt->i915->drm.struct_mutex);
 	if (IS_ERR(ctx)) {
 		err = PTR_ERR(ctx);
 		goto out;
@@ -458,9 +464,7 @@ static int igt_reset_nop_engine(void *arg)
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
 	ctx = live_context(gt->i915, file);
-	mutex_unlock(&gt->i915->drm.struct_mutex);
 	if (IS_ERR(ctx)) {
 		err = PTR_ERR(ctx);
 		goto out;
@@ -705,9 +709,7 @@ static int active_engine(void *data)
 		return PTR_ERR(file);
 
 	for (count = 0; count < ARRAY_SIZE(ctx); count++) {
-		mutex_lock(&engine->i915->drm.struct_mutex);
 		ctx[count] = live_context(engine->i915, file);
-		mutex_unlock(&engine->i915->drm.struct_mutex);
 		if (IS_ERR(ctx[count])) {
 			err = PTR_ERR(ctx[count]);
 			while (--count)
@@ -1291,6 +1293,7 @@ static int igt_reset_evict_ppgtt(void *arg)
 {
 	struct intel_gt *gt = arg;
 	struct i915_gem_context *ctx;
+	struct i915_address_space *vm;
 	struct drm_file *file;
 	int err;
 
@@ -1298,18 +1301,20 @@ static int igt_reset_evict_ppgtt(void *arg)
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	mutex_lock(&gt->i915->drm.struct_mutex);
 	ctx = live_context(gt->i915, file);
-	mutex_unlock(&gt->i915->drm.struct_mutex);
 	if (IS_ERR(ctx)) {
 		err = PTR_ERR(ctx);
 		goto out;
 	}
 
 	err = 0;
-	if (ctx->vm) /* aliasing == global gtt locking, covered above */
-		err = __igt_reset_evict_vma(gt, ctx->vm,
+	vm = i915_gem_context_get_vm_rcu(ctx);
+	if (!i915_is_ggtt(vm)) {
+		/* aliasing == global gtt locking, covered above */
+		err = __igt_reset_evict_vma(gt, vm,
 					    evict_vma, EXEC_OBJECT_WRITE);
+	}
+	i915_vm_put(vm);
 
 out:
 	mock_file_free(gt->i915, file);
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 04c1cf573642..8dc42c5c7569 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -1631,7 +1631,11 @@ static int smoke_submit(struct preempt_smoke *smoke,
 	int err = 0;
 
 	if (batch) {
-		vma = i915_vma_instance(batch, ctx->vm, NULL);
+		struct i915_address_space *vm;
+
+		vm = i915_gem_context_get_vm_rcu(ctx);
+		vma = i915_vma_instance(batch, vm, NULL);
+		i915_vm_put(vm);
 		if (IS_ERR(vma))
 			return PTR_ERR(vma);
 
diff --git a/drivers/gpu/drm/i915/gt/selftest_workarounds.c b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
index 4ee2e2babd0d..7c7aceb85a74 100644
--- a/drivers/gpu/drm/i915/gt/selftest_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
@@ -260,7 +260,6 @@ switch_to_scratch_context(struct intel_engine_cs *engine,
 		rq = igt_spinner_create_request(spin, ce, MI_NOOP);
 
 	intel_context_put(ce);
-	kernel_context_close(ctx);
 
 	if (IS_ERR(rq)) {
 		spin = NULL;
@@ -279,6 +278,7 @@ err:
 	if (err && spin)
 		igt_spinner_end(spin);
 
+	kernel_context_close(ctx);
 	return err;
 }
 
@@ -355,6 +355,7 @@ out_ctx:
 static struct i915_vma *create_batch(struct i915_gem_context *ctx)
 {
 	struct drm_i915_gem_object *obj;
+	struct i915_address_space *vm;
 	struct i915_vma *vma;
 	int err;
 
@@ -362,7 +363,9 @@ static struct i915_vma *create_batch(struct i915_gem_context *ctx)
 	if (IS_ERR(obj))
 		return ERR_CAST(obj);
 
-	vma = i915_vma_instance(obj, ctx->vm, NULL);
+	vm = i915_gem_context_get_vm_rcu(ctx);
+	vma = i915_vma_instance(obj, vm, NULL);
+	i915_vm_put(vm);
 	if (IS_ERR(vma)) {
 		err = PTR_ERR(vma);
 		goto err_obj;
@@ -463,12 +466,15 @@ static int check_dirty_whitelist(struct i915_gem_context *ctx,
 		0xffff00ff,
 		0xffffffff,
 	};
+	struct i915_address_space *vm;
 	struct i915_vma *scratch;
 	struct i915_vma *batch;
 	int err = 0, i, v;
 	u32 *cs, *results;
 
-	scratch = create_scratch(ctx->vm, 2 * ARRAY_SIZE(values) + 1);
+	vm = i915_gem_context_get_vm_rcu(ctx);
+	scratch = create_scratch(vm, 2 * ARRAY_SIZE(values) + 1);
+	i915_vm_put(vm);
 	if (IS_ERR(scratch))
 		return PTR_ERR(scratch);
 
@@ -1010,6 +1016,7 @@ static int live_isolated_whitelist(void *arg)
 		return 0;
 
 	for (i = 0; i < ARRAY_SIZE(client); i++) {
+		struct i915_address_space *vm;
 		struct i915_gem_context *c;
 
 		c = kernel_context(i915);
@@ -1018,22 +1025,27 @@ static int live_isolated_whitelist(void *arg)
 			goto err;
 		}
 
-		client[i].scratch[0] = create_scratch(c->vm, 1024);
+		vm = i915_gem_context_get_vm_rcu(c);
+
+		client[i].scratch[0] = create_scratch(vm, 1024);
 		if (IS_ERR(client[i].scratch[0])) {
 			err = PTR_ERR(client[i].scratch[0]);
+			i915_vm_put(vm);
 			kernel_context_close(c);
 			goto err;
 		}
 
-		client[i].scratch[1] = create_scratch(c->vm, 1024);
+		client[i].scratch[1] = create_scratch(vm, 1024);
 		if (IS_ERR(client[i].scratch[1])) {
 			err = PTR_ERR(client[i].scratch[1]);
 			i915_vma_unpin_and_release(&client[i].scratch[0], 0);
+			i915_vm_put(vm);
 			kernel_context_close(c);
 			goto err;
 		}
 
 		client[i].ctx = c;
+		i915_vm_put(vm);
 	}
 
 	for_each_engine(engine, i915, id) {