[Intel-xe] [RFC PATCH 3/7] drm/xe: Allow num_binds == 0 in VM bind IOCTL

[Matthew Brost <matthew.brost@intel.com>]

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 vkQueueWaitIdle easily.

v2: s/vkQueueWaitForIdle/vkQueueWaitIdle

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/xe/xe_sync.c |  4 ++++
 drivers/gpu/drm/xe/xe_sync.h |  1 +
 drivers/gpu/drm/xe/xe_vm.c   | 36 ++++++++++++++++++++++--------------
 3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_sync.c b/drivers/gpu/drm/xe/xe_sync.c
index 2a3f508722fc..d0f118223fa2 100644
--- a/drivers/gpu/drm/xe/xe_sync.c
+++ b/drivers/gpu/drm/xe/xe_sync.c
@@ -104,6 +104,7 @@ int xe_sync_entry_parse(struct xe_device *xe, struct xe_file *xef,
 	int err;
 	bool exec = flags & SYNC_PARSE_FLAG_EXEC;
 	bool in_lr_mode = flags & SYNC_PARSE_FLAG_LR_MODE;
+	bool disallow_user_fence = flags & SYNC_PARSE_FLAG_DISALLOW_USER_FENCE;
 	bool signal;
 
 	if (copy_from_user(&sync_in, sync_user, sizeof(*sync_user)))
@@ -164,6 +165,9 @@ int xe_sync_entry_parse(struct xe_device *xe, struct xe_file *xef,
 		break;
 
 	case DRM_XE_SYNC_TYPE_USER_FENCE:
+		if (XE_IOCTL_DBG(xe, disallow_user_fence))
+			return -EOPNOTSUPP;
+
 		if (XE_IOCTL_DBG(xe, !signal))
 			return -EOPNOTSUPP;
 
diff --git a/drivers/gpu/drm/xe/xe_sync.h b/drivers/gpu/drm/xe/xe_sync.h
index 1b748cec4678..45f4371e94b9 100644
--- a/drivers/gpu/drm/xe/xe_sync.h
+++ b/drivers/gpu/drm/xe/xe_sync.h
@@ -14,6 +14,7 @@ struct xe_sched_job;
 
 #define SYNC_PARSE_FLAG_EXEC			BIT(0)
 #define SYNC_PARSE_FLAG_LR_MODE			BIT(1)
+#define SYNC_PARSE_FLAG_DISALLOW_USER_FENCE	BIT(2)
 
 int xe_sync_entry_parse(struct xe_device *xe, struct xe_file *xef,
 			struct xe_sync_entry *sync,
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 42077e3db36a..f6de0584ea91 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2834,7 +2834,6 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe,
 		return -EINVAL;
 
 	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;
 
@@ -2987,7 +2986,7 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 			goto put_exec_queue;
 		}
 
-		if (XE_IOCTL_DBG(xe, async !=
+		if (XE_IOCTL_DBG(xe, args->num_binds && async !=
 				 !!(q->flags & EXEC_QUEUE_FLAG_VM_ASYNC))) {
 			err = -EINVAL;
 			goto put_exec_queue;
@@ -3001,7 +3000,7 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 	}
 
 	if (!args->exec_queue_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;
@@ -3028,16 +3027,18 @@ 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 = kcalloc(args->num_binds, sizeof(*bos), 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 = kcalloc(args->num_binds, sizeof(*ops), GFP_KERNEL);
+		if (!ops) {
+			err = -ENOMEM;
+			goto release_vm_lock;
+		}
 	}
 
 	for (i = 0; i < args->num_binds; ++i) {
@@ -3107,12 +3108,19 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 	for (num_syncs = 0; num_syncs < args->num_syncs; num_syncs++) {
 		err = xe_sync_entry_parse(xe, xef, &syncs[num_syncs],
 					  &syncs_user[num_syncs],
-					  xe_vm_in_lr_mode(vm) ?
-					  SYNC_PARSE_FLAG_LR_MODE : 0);
+					  (xe_vm_in_lr_mode(vm) ?
+					   SYNC_PARSE_FLAG_LR_MODE : 0) |
+					  (!args->num_binds ?
+					   SYNC_PARSE_FLAG_DISALLOW_USER_FENCE : 0));
 		if (err)
 			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