[RFC PATCH v3 08/17] drm/i915/vm_bind: Add out fence support

[Niranjana Vishwanathapura]

On Sat, Aug 27, 2022 at 09:43:54PM +0200, Andi Shyti wrote:
>From: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
>
>Add support for handling out fence of vm_bind call.
>
>Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
>Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
>Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
>---
> drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h   |  3 +
> .../drm/i915/gem/i915_gem_vm_bind_object.c    | 82 +++++++++++++++++++
> drivers/gpu/drm/i915/i915_vma.c               |  6 +-
> drivers/gpu/drm/i915/i915_vma_types.h         |  7 ++
> 4 files changed, 97 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
>index ebc493b7dafc1..d65e6e4fb3972 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
>@@ -18,4 +18,7 @@ int i915_gem_vm_unbind_ioctl(struct drm_device *dev, void *data,
> 			     struct drm_file *file);
>
> void i915_gem_vm_unbind_vma_all(struct i915_address_space *vm);
>+void i915_vm_bind_signal_fence(struct i915_vma *vma,
>+			       struct dma_fence * const fence);
>+
> #endif /* __I915_GEM_VM_BIND_H */
>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>index 3b45529fe8d4c..e57b9c492a7f9 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>@@ -5,6 +5,8 @@
>
> #include <linux/interval_tree_generic.h>
>
>+#include <drm/drm_syncobj.h>
>+
> #include "gem/i915_gem_vm_bind.h"
> #include "gem/i915_gem_context.h"
> #include "gt/gen8_engine_cs.h"
>@@ -109,6 +111,67 @@ void i915_gem_vm_bind_remove(struct i915_vma *vma, bool release_obj)
> 	}
> }
>
>+static int i915_vm_bind_add_fence(struct drm_file *file, struct i915_vma *vma,
>+				  u32 handle, u64 point)
>+{
>+	struct drm_syncobj *syncobj;
>+
>+	syncobj = drm_syncobj_find(file, handle);
>+	if (!syncobj) {
>+		DRM_DEBUG("Invalid syncobj handle provided\n");
>+		return -ENOENT;
>+	}
>+
>+	/*
>+	 * For timeline syncobjs we need to preallocate chains for
>+	 * later signaling.
>+	 */
>+	if (point) {
>+		vma->vm_bind_fence.chain_fence = dma_fence_chain_alloc();
>+		if (!vma->vm_bind_fence.chain_fence) {
>+			drm_syncobj_put(syncobj);
>+			return -ENOMEM;
>+		}
>+	} else {
>+		vma->vm_bind_fence.chain_fence = NULL;
>+	}
>+	vma->vm_bind_fence.syncobj = syncobj;
>+	vma->vm_bind_fence.value = point;
>+
>+	return 0;
>+}
>+
>+static void i915_vm_bind_put_fence(struct i915_vma *vma)
>+{
>+	if (!vma->vm_bind_fence.syncobj)
>+		return;
>+
>+	drm_syncobj_put(vma->vm_bind_fence.syncobj);
>+	dma_fence_chain_free(vma->vm_bind_fence.chain_fence);
>+}
>+
>+void i915_vm_bind_signal_fence(struct i915_vma *vma,
>+			       struct dma_fence * const fence)
>+{
>+	struct drm_syncobj *syncobj = vma->vm_bind_fence.syncobj;
>+
>+	if (!syncobj)
>+		return;
>+
>+	if (vma->vm_bind_fence.chain_fence) {
>+		drm_syncobj_add_point(syncobj,
>+				      vma->vm_bind_fence.chain_fence,
>+				      fence, vma->vm_bind_fence.value);
>+		/*
>+		 * The chain's ownership is transferred to the
>+		 * timeline.
>+		 */
>+		vma->vm_bind_fence.chain_fence = NULL;
>+	} else {
>+		drm_syncobj_replace_fence(syncobj, fence);
>+	}
>+}
>+
> static int i915_gem_vm_unbind_vma(struct i915_address_space *vm,
> 				  struct i915_vma *vma,
> 				  struct drm_i915_gem_vm_unbind *va)
>@@ -243,6 +306,15 @@ static int i915_gem_vm_bind_obj(struct i915_address_space *vm,
> 		goto unlock_vm;
> 	}
>
>+	if (va->fence.flags & I915_TIMELINE_FENCE_SIGNAL) {
>+		ret = i915_vm_bind_add_fence(file, vma, va->fence.handle,
>+					     va->fence.value);
>+		if (ret)
>+			goto put_vma;
>+	}
>+
>+	pin_flags = va->start | PIN_OFFSET_FIXED | PIN_USER;

Setting pin_flags should part of patch #4.

>+
> 	for_i915_gem_ww(&ww, ret, true) {
> retry:
> 		ret = i915_gem_object_lock(vma->obj, &ww);
>@@ -267,12 +339,22 @@ static int i915_gem_vm_bind_obj(struct i915_address_space *vm,
> 			ret = i915_gem_ww_ctx_backoff(&ww);
> 			if (!ret)
> 				goto retry;
>+

Redundent white space. remove.

> 		} else {
> 			/* Hold object reference until vm_unbind */
> 			i915_gem_object_get(vma->obj);
> 		}
> 	}
>
>+	if (va->fence.flags & I915_TIMELINE_FENCE_SIGNAL)
>+		i915_vm_bind_put_fence(vma);
>+
>+put_vma:
>+	if (ret && vma) {
>+		i915_vma_set_freed(vma);
>+		i915_vma_destroy(vma);
>+	}
>+

I think destroying vma upon error should be part of patch #4.

Niranjana

> unlock_vm:
> 	mutex_unlock(&vm->vm_bind_lock);
>
>diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
>index 0eb7727d62a6f..6ca37ce2b35a8 100644
>--- a/drivers/gpu/drm/i915/i915_vma.c
>+++ b/drivers/gpu/drm/i915/i915_vma.c
>@@ -1542,8 +1542,12 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
> err_vma_res:
> 	i915_vma_resource_free(vma_res);
> err_fence:
>-	if (work)
>+	if (work) {
>+		if (i915_vma_is_persistent(vma))
>+			i915_vm_bind_signal_fence(vma, &work->base.dma);
>+
> 		dma_fence_work_commit_imm(&work->base);
>+	}
> err_rpm:
> 	if (wakeref)
> 		intel_runtime_pm_put(&vma->vm->i915->runtime_pm, wakeref);
>diff --git a/drivers/gpu/drm/i915/i915_vma_types.h b/drivers/gpu/drm/i915/i915_vma_types.h
>index 5483ccf0c82c7..8bf870a0f689b 100644
>--- a/drivers/gpu/drm/i915/i915_vma_types.h
>+++ b/drivers/gpu/drm/i915/i915_vma_types.h
>@@ -318,6 +318,13 @@ struct i915_vma {
> 	/* @vm_rebind_link: link to vm_rebind_list and protected by vm_rebind_lock */
> 	struct list_head vm_rebind_link; /* Link in vm_rebind_list */
>
>+	/** Timeline fence for vm_bind completion notification */
>+	struct {
>+		struct drm_syncobj *syncobj;
>+		u64 value;
>+		struct dma_fence_chain *chain_fence;
>+	} vm_bind_fence;
>+
> 	/** Interval tree structures for persistent vma */
>
> 	/** @rb: node for the interval tree of vm for persistent vmas */
>-- 
>2.34.1
>