drm/ttm: convert to unified vma offset manager

Use the new vma-manager infrastructure. This doesn't change any
implementation details as the vma-offset-manager is nearly copied 1-to-1
from TTM.

The vm_lock is moved into the offset manager so we can drop it from TTM.
During lookup, we use the vma locking helpers to take a reference to the
found object.
In all other scenarios, locking stays the same as before. We always
guarantee that drm_vma_offset_remove() is called only during destruction.
Hence, helpers like drm_vma_node_offset_addr() are always safe as long as
the node has a valid offset.

This also drops the addr_space_offset member as it is a copy of vm_start
in vma_node objects. Use the accessor functions instead.

v4:
 - remove vm_lock
 - use drm_vma_offset_lock_lookup() to protect lookup (instead of vm_lock)

Cc: Dave Airlie <airlied@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Martin Peres <martin.peres@labri.fr>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>

1 files changed, 31 insertions, 50 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 3df9f16b041c..8c0e2c020215 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -33,6 +33,7 @@
 #include <ttm/ttm_module.h>
 #include <ttm/ttm_bo_driver.h>
 #include <ttm/ttm_placement.h>
+#include <drm/drm_vma_manager.h>
 #include <linux/mm.h>
 #include <linux/rbtree.h>
 #include <linux/module.h>
@@ -40,37 +41,6 @@
 
 #define TTM_BO_VM_NUM_PREFAULT 16
 
-static struct ttm_buffer_object *ttm_bo_vm_lookup_rb(struct ttm_bo_device *bdev,
-						     unsigned long page_start,
-						     unsigned long num_pages)
-{
-	struct rb_node *cur = bdev->addr_space_rb.rb_node;
-	unsigned long cur_offset;
-	struct ttm_buffer_object *bo;
-	struct ttm_buffer_object *best_bo = NULL;
-
-	while (likely(cur != NULL)) {
-		bo = rb_entry(cur, struct ttm_buffer_object, vm_rb);
-		cur_offset = bo->vm_node->start;
-		if (page_start >= cur_offset) {
-			cur = cur->rb_right;
-			best_bo = bo;
-			if (page_start == cur_offset)
-				break;
-		} else
-			cur = cur->rb_left;
-	}
-
-	if (unlikely(best_bo == NULL))
-		return NULL;
-
-	if (unlikely((best_bo->vm_node->start + best_bo->num_pages) <
-		     (page_start + num_pages)))
-		return NULL;
-
-	return best_bo;
-}
-
 static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
@@ -146,9 +116,9 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	}
 
 	page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
-	    bo->vm_node->start - vma->vm_pgoff;
+	    drm_vma_node_start(&bo->vma_node) - vma->vm_pgoff;
 	page_last = vma_pages(vma) +
-	    bo->vm_node->start - vma->vm_pgoff;
+	    drm_vma_node_start(&bo->vma_node) - vma->vm_pgoff;
 
 	if (unlikely(page_offset >= bo->num_pages)) {
 		retval = VM_FAULT_SIGBUS;
@@ -249,6 +219,30 @@ static const struct vm_operations_struct ttm_bo_vm_ops = {
 	.close = ttm_bo_vm_close
 };
 
+static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,
+						  unsigned long offset,
+						  unsigned long pages)
+{
+	struct drm_vma_offset_node *node;
+	struct ttm_buffer_object *bo = NULL;
+
+	drm_vma_offset_lock_lookup(&bdev->vma_manager);
+
+	node = drm_vma_offset_lookup_locked(&bdev->vma_manager, offset, pages);
+	if (likely(node)) {
+		bo = container_of(node, struct ttm_buffer_object, vma_node);
+		if (!kref_get_unless_zero(&bo->kref))
+			bo = NULL;
+	}
+
+	drm_vma_offset_unlock_lookup(&bdev->vma_manager);
+
+	if (!bo)
+		pr_err("Could not find buffer object to map\n");
+
+	return bo;
+}
+
 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 		struct ttm_bo_device *bdev)
 {
@@ -256,17 +250,9 @@ int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 	struct ttm_buffer_object *bo;
 	int ret;
 
-	read_lock(&bdev->vm_lock);
-	bo = ttm_bo_vm_lookup_rb(bdev, vma->vm_pgoff,
-				 vma_pages(vma));
-	if (likely(bo != NULL) && !kref_get_unless_zero(&bo->kref))
-		bo = NULL;
-	read_unlock(&bdev->vm_lock);
-
-	if (unlikely(bo == NULL)) {
-		pr_err("Could not find buffer object to map\n");
+	bo = ttm_bo_vm_lookup(bdev, vma->vm_pgoff, vma_pages(vma));
+	if (unlikely(!bo))
 		return -EINVAL;
-	}
 
 	driver = bo->bdev->driver;
 	if (unlikely(!driver->verify_access)) {
@@ -324,12 +310,7 @@ ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
 	bool no_wait = false;
 	bool dummy;
 
-	read_lock(&bdev->vm_lock);
-	bo = ttm_bo_vm_lookup_rb(bdev, dev_offset, 1);
-	if (likely(bo != NULL))
-		ttm_bo_reference(bo);
-	read_unlock(&bdev->vm_lock);
-
+	bo = ttm_bo_vm_lookup(bdev, dev_offset, 1);
 	if (unlikely(bo == NULL))
 		return -EFAULT;
 
@@ -343,7 +324,7 @@ ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
 	if (unlikely(ret != 0))
 		goto out_unref;
 
-	kmap_offset = dev_offset - bo->vm_node->start;
+	kmap_offset = dev_offset - drm_vma_node_start(&bo->vma_node);
 	if (unlikely(kmap_offset >= bo->num_pages)) {
 		ret = -EFBIG;
 		goto out_unref;