[Intel-xe] [PATCH 3/5] drm/xe: Allow num_binds == 0 in VM bind IOCTL

[Matthew Brost]

The idea being out-syncs can signal indicating all previous operations
on the bind queue are complete. An example use case of this would be
support for implementing vkQueueWaitForIdle easily.

Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_vm.c | 39 +++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 3e420b2c12b4..874ef9afbecf 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2717,7 +2717,6 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe,
 	int i;
 
 	if (XE_IOCTL_DBG(xe, args->extensions) ||
-	    XE_IOCTL_DBG(xe, !args->num_binds) ||
 	    XE_IOCTL_DBG(xe, args->num_binds > MAX_BINDS))
 		return -EINVAL;
 
@@ -2855,7 +2854,7 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 			goto put_engine;
 		}
 
-		if (XE_IOCTL_DBG(xe, async !=
+		if (XE_IOCTL_DBG(xe, args->num_binds && async !=
 				 !!(e->flags & ENGINE_FLAG_VM_ASYNC))) {
 			err = -EINVAL;
 			goto put_engine;
@@ -2869,7 +2868,7 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 	}
 
 	if (!args->engine_id) {
-		if (XE_IOCTL_DBG(xe, async !=
+		if (XE_IOCTL_DBG(xe, args->num_binds && async !=
 				 !!(vm->flags & XE_VM_FLAG_ASYNC_DEFAULT))) {
 			err = -EINVAL;
 			goto put_vm;
@@ -2885,17 +2884,20 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 		goto release_vm_lock;
 	}
 
-	if (XE_IOCTL_DBG(xe, vm->ops_state.error && !reclaim)) {
+	if (XE_IOCTL_DBG(xe, args->num_binds &&
+			 vm->ops_state.error && !reclaim)) {
 		err = -EALREADY;
 		goto release_vm_lock;
 	}
 
-	if (XE_IOCTL_DBG(xe, !vm->ops_state.error && reclaim)) {
+	if (XE_IOCTL_DBG(xe, args->num_binds &&
+			 !vm->ops_state.error && reclaim)) {
 		err = -EINVAL;
 		goto release_vm_lock;
 	}
 
-	if (VM_BIND_OP(bind_ops[0].op) == XE_VM_BIND_OP_RESTART) {
+	if (args->num_binds &&
+	    VM_BIND_OP(bind_ops[0].op) == XE_VM_BIND_OP_RESTART) {
 		if (XE_IOCTL_DBG(xe, args->num_syncs))
 			err = EINVAL;
 		if (XE_IOCTL_DBG(xe, !err && !vm->ops_state.error))
@@ -2931,16 +2933,18 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 		}
 	}
 
-	bos = kzalloc(sizeof(*bos) * args->num_binds, GFP_KERNEL);
-	if (!bos) {
-		err = -ENOMEM;
-		goto release_vm_lock;
-	}
+	if (args->num_binds) {
+		bos = kzalloc(sizeof(*bos) * args->num_binds, GFP_KERNEL);
+		if (!bos) {
+			err = -ENOMEM;
+			goto release_vm_lock;
+		}
 
-	ops = kzalloc(sizeof(*ops) * args->num_binds, GFP_KERNEL);
-	if (!ops) {
-		err = -ENOMEM;
-		goto release_vm_lock;
+		ops = kzalloc(sizeof(*ops) * args->num_binds, GFP_KERNEL);
+		if (!ops) {
+			err = -ENOMEM;
+			goto release_vm_lock;
+		}
 	}
 
 	for (i = 0; i < args->num_binds; ++i) {
@@ -2995,6 +2999,11 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 			goto free_syncs;
 	}
 
+	if (!args->num_binds) {
+		err = -ENODATA;
+		goto free_syncs;
+	}
+
 	for (i = 0; i < args->num_binds; ++i) {
 		u64 range = bind_ops[i].range;
 		u64 addr = bind_ops[i].addr;
-- 
2.34.1