[PATCH 4/4] drm: Add four ioctls for managing drm mode object leases

[Keith Packard]

drm_mode_create_lease

	Creates a lease for a list of drm mode objects, returning an
	fd for the new drm_master and a 64-bit identifier for the lessee

drm_mode_list_lesees

	List the identifiers of the lessees from a particular lessor

drm_mode_get_lease

	List the leased objects for a particular lessee

drm_mode_change_lease

	Adjust the terms of a lease, adding or removing resources or
	switching from masking to non-masking.

This should suffice to at least create, query and manage available
leases.

Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
 drivers/gpu/drm/drm_ioctl.c |   4 +
 drivers/gpu/drm/drm_lease.c | 309 ++++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_lease.h     |  12 ++
 include/uapi/drm/drm.h      |   4 +
 include/uapi/drm/drm_mode.h |  78 +++++++++++
 5 files changed, 407 insertions(+)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index fed22c2b98b6..0f9e3c0fe2ac 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -636,6 +636,10 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATOMIC, drm_mode_atomic_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATEPROPBLOB, drm_mode_createblob_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DESTROYPROPBLOB, drm_mode_destroyblob_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE, drm_mode_create_lease_ioctl, DRM_ANY_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, drm_mode_list_lessees_ioctl, DRM_ANY_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_ANY_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CHANGE_LEASE, drm_mode_change_lease_ioctl, DRM_ANY_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 };
 
 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
index 782005c7706d..39131860bcd3 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -483,3 +483,312 @@ void drm_lease_destroy(struct drm_master *master)
 
 	DRM_DEBUG_LEASE("drm_lease_destroy done %d\n", master->lessee_id);
 }
+
+/**
+ * drm_mode_create_lease_ioctl - create a new lease
+ * @dev: the drm device
+ * @data: pointer to struct drm_mode_create_lease
+ * @file_priv: the file being manipulated
+ *
+ * The master associated with the specified file will have a lease
+ * created containing the objects specified in the ioctl structure.
+ * A file descriptor will be allocated for that and returned to the
+ * application.
+ */
+int drm_mode_create_lease_ioctl(struct drm_device *dev,
+				void *data, struct drm_file *lessor_priv)
+{
+	struct drm_mode_create_lease *cl = data;
+	size_t object_count;
+	size_t o;
+	int ret = 0;
+	struct idr leases;
+	struct drm_master *lessor = lessor_priv->master;
+	struct drm_master *lessee = NULL;
+	struct file *lessee_file = NULL;
+	struct file *lessor_file = lessor_priv->filp;
+	struct drm_file *lessee_priv;
+	int fd = -1;
+
+	object_count = cl->object_count;
+	idr_init(&leases);
+
+	fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));
+
+	DRM_DEBUG_LEASE("Creating new lease\n");
+
+	/* Lookup the mode objects and add their IDs to the lease request */
+	for (o = 0; o < object_count; o++) {
+		__u32 object_id;
+
+		if (copy_from_user(&object_id,
+				   u64_to_user_ptr(cl->object_ids) + o * sizeof (__u32),
+				   sizeof (__u32))) {
+			ret = -EFAULT;
+			goto bail;
+		}
+		DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id);
+
+		ret = idr_alloc(&leases, (void *) 1, object_id, object_id + 1, GFP_KERNEL);
+		if (ret < 0) {
+			DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
+					object_id, ret);
+			goto bail;
+		}
+	}
+
+	mutex_lock(&dev->master_mutex);
+
+	DRM_DEBUG_LEASE("Creating lease\n");
+	lessee = drm_lease_create(lessor, cl->mask_lease != 0, &leases);
+
+	if (IS_ERR(lessee)) {
+		ret = PTR_ERR(lessee);
+		lessee = NULL;
+		mutex_unlock(&dev->master_mutex);
+		goto bail;
+	}
+
+	/* Clone the lessor file to create a new file for us */
+	DRM_DEBUG_LEASE("Allocating lease file\n");
+	path_get(&lessor_file->f_path);
+	lessee_file = alloc_file(&lessor_file->f_path,
+				 lessor_file->f_mode,
+				 fops_get(lessor_file->f_inode->i_fop));
+
+	if (IS_ERR(lessee_file)) {
+		ret = PTR_ERR(lessee_file);
+		lessee_file = NULL;
+		mutex_unlock(&dev->master_mutex);
+		goto bail;
+	}
+
+	mutex_unlock(&dev->master_mutex);
+
+	/* Initialize the new file for DRM */
+	DRM_DEBUG_LEASE("Initializing the file with %p\n", lessee_file->f_op->open);
+	ret = lessee_file->f_op->open(lessee_file->f_inode, lessee_file);
+	if (ret)
+		goto bail;
+
+	lessee_priv = lessee_file->private_data;
+
+	/* Change the file to a master one */
+	drm_master_put(&lessee_priv->master);
+	lessee_priv->master = lessee;
+	lessee_priv->is_master = 1;
+	lessee_priv->authenticated = 1;
+
+	/* Hook up the fd */
+	fd_install(fd, lessee_file);
+
+	/* Pass fd back to userspace */
+	DRM_DEBUG_LEASE("Returning fd %d id %d\n", fd, lessee->lessee_id);
+	cl->fd = fd;
+	cl->lessee_id = lessee->lessee_id;
+
+	/* and don't destroy our resources */
+	fd = -1;
+	lessee = NULL;
+	lessee_file = NULL;
+
+	ret = 0;
+
+bail:
+
+	if (lessee_file) {
+		DRM_DEBUG_LEASE("Freeing lessee file\n");
+		fput(lessee_file);
+	}
+
+	if (lessee) {
+		DRM_DEBUG_LEASE("Freeing lessee drm_master\n");
+		drm_master_put(&lessee);
+	}
+
+	idr_destroy(&leases);
+
+	if (fd != -1) {
+		DRM_DEBUG_LEASE("Freeing unused fd\n");
+		put_unused_fd(fd);
+	}
+
+	DRM_DEBUG_LEASE("Return %d from drm_mode_create_lease_ioctl\n", ret);
+	return ret;
+}
+
+/**
+ * drm_mode_list_lessees_ioctl - list lessee ids
+ * @dev: the drm device
+ * @data: pointer to struct drm_mode_create_lease
+ * @file_priv: the file being manipulated
+ *
+ * Starting from the master associated with the specified file,
+ * the master with the provided lessee_id is found, and then
+ * an array of lessee ids associated with leases from that master
+ * are returned.
+ */
+
+int drm_mode_list_lessees_ioctl(struct drm_device *dev,
+			       void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_list_lessees *arg = data;
+	__u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
+	__u32 count_lessees = arg->count_lessees;
+	struct drm_master *lessor, *lessee;
+	int count;
+	int ret = 0;
+
+	DRM_DEBUG_LEASE("List lessees for %d\n", arg->lessor_id);
+
+	mutex_lock(&dev->master_mutex);
+
+	/* Search the tree for the requested drm_master */
+	lessor = drm_lessee_get(file_priv->master, arg->lessor_id);
+	if (!lessor) {
+		DRM_DEBUG_LEASE("No such lessor %d\n", arg->lessor_id);
+		mutex_unlock(&dev->master_mutex);
+		return -ENOENT;
+	}
+
+	count = 0;
+	drm_for_each_lessee(lessee, lessor) {
+		if (count_lessees > count) {
+			DRM_DEBUG_LEASE("Add lessee %d\n", lessee->lessee_id);
+			ret = put_user(lessee->lessee_id, lessee_ids + count);
+			if (ret)
+				break;
+		}
+		count++;
+	}
+
+	DRM_DEBUG_LEASE("Lessor leases to %d\n", count);
+	if (ret == 0)
+		arg->count_lessees = count;
+
+	drm_master_put(&lessor);
+
+	mutex_unlock(&dev->master_mutex);
+
+	return ret;
+}
+
+/**
+ * drm_mode_get_lease_ioctl - list leased objects
+ * @dev: the drm device
+ * @data: pointer to struct drm_mode_create_lease
+ * @file_priv: the file being manipulated
+ *
+ * Return the list of leased objects for the specified lessee
+ */
+
+int drm_mode_get_lease_ioctl(struct drm_device *dev,
+			     void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_get_lease *arg = data;
+	__u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
+	__u32 count_objects = arg->count_objects;
+	struct drm_master *lessee;
+	struct idr *object_idr;
+	int count;
+	void *entry;
+	int object;
+	int ret = 0;
+
+	DRM_DEBUG_LEASE("get lease for %d\n", arg->lessee_id);
+
+	mutex_lock(&dev->master_mutex);
+
+	/* Search the tree for the requested drm_master */
+	lessee = drm_lessee_get(file_priv->master, arg->lessee_id);
+	if (!lessee) {
+		mutex_unlock(&dev->master_mutex);
+		DRM_DEBUG_LEASE("No such lessee %d\n", arg->lessee_id);
+		return -ENOENT;
+	}
+
+	if (lessee->lessor == NULL)
+		object_idr = &lessee->dev->mode_config.crtc_idr;
+	else
+		object_idr = &lessee->leases;
+
+	count = 0;
+	idr_for_each_entry(object_idr, entry, object) {
+		if (count_objects > count) {
+			DRM_DEBUG_LEASE("adding object %d\n", object);
+			ret = put_user(object, object_ids + count);
+			if (ret)
+				break;
+		}
+		count++;
+	}
+
+	DRM_DEBUG("lease holds %d objects\n", count);
+	if (ret == 0)
+		arg->count_objects = count;
+
+	drm_master_put(&lessee);
+
+	mutex_unlock(&dev->master_mutex);
+
+	return ret;
+}
+
+/**
+ * drm_mode_change_lease_ioctl - change the objects in a lease
+ * @dev: the drm device
+ * @data: pointer to struct drm_mode_create_lease
+ * @file_priv: the file being manipulated
+ *
+ * The master associated with the specified file will have a lease
+ * created containing the objects specified in the ioctl structure.
+ * A file descriptor will be allocated for that and returned to the
+ * application.
+ */
+int drm_mode_change_lease_ioctl(struct drm_device *dev,
+				void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_create_lease *cl = data;
+	size_t object_count;
+	size_t o;
+	int ret = 0;
+	struct idr leases;
+	struct drm_master *lessor = file_priv->master;
+
+	object_count = cl->object_count;
+	idr_init(&leases);
+
+	DRM_DEBUG_LEASE("Changing existing lease\n");
+
+	/* Lookup the mode objects and add their IDs to the lease request */
+	for (o = 0; o < object_count; o++) {
+		__u32 object_id;
+
+		if (copy_from_user(&object_id,
+				   u64_to_user_ptr(cl->object_ids) + o * sizeof (__u32),
+				   sizeof (__u32))) {
+			return -EFAULT;
+		}
+		DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id);
+
+		ret = idr_alloc(&leases, (void *) 1, object_id, object_id + 1, GFP_KERNEL);
+		if (ret < 0) {
+			DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
+					object_id, ret);
+			return ret;
+		}
+	}
+
+	mutex_lock(&dev->master_mutex);
+
+	DRM_DEBUG_LEASE("Change lease\n");
+
+	ret = drm_lease_change(lessor, cl->lessee_id, cl->mask_lease != 0, &leases);
+
+	mutex_unlock(&dev->master_mutex);
+
+	idr_destroy(&leases);
+
+	DRM_DEBUG_LEASE("Return %d from drm_mode_change_lease_ioctl\n", ret);
+	return ret;
+}
diff --git a/include/drm/drm_lease.h b/include/drm/drm_lease.h
index 8f91fc4226e3..367b57698f53 100644
--- a/include/drm/drm_lease.h
+++ b/include/drm/drm_lease.h
@@ -52,4 +52,16 @@ uint32_t drm_lease_filter_crtcs(struct drm_master *master, uint32_t crtcs);
 
 uint32_t drm_lease_filter_encoders(struct drm_master *master, uint32_t encoders);
 
+int drm_mode_create_lease_ioctl(struct drm_device *dev,
+				void *data, struct drm_file *file_priv);
+
+int drm_mode_list_lessees_ioctl(struct drm_device *dev,
+				void *data, struct drm_file *file_priv);
+
+int drm_mode_get_lease_ioctl(struct drm_device *dev,
+			     void *data, struct drm_file *file_priv);
+
+int drm_mode_change_lease_ioctl(struct drm_device *dev,
+				void *data, struct drm_file *file_priv);
+
 #endif /* _DRM_LEASE_H_ */
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index b2c52843bc70..8c62da23d7a3 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -813,6 +813,10 @@ extern "C" {
 #define DRM_IOCTL_MODE_ATOMIC		DRM_IOWR(0xBC, struct drm_mode_atomic)
 #define DRM_IOCTL_MODE_CREATEPROPBLOB	DRM_IOWR(0xBD, struct drm_mode_create_blob)
 #define DRM_IOCTL_MODE_DESTROYPROPBLOB	DRM_IOWR(0xBE, struct drm_mode_destroy_blob)
+#define DRM_IOCTL_MODE_CREATE_LEASE	DRM_IOWR(0xBF, struct drm_mode_create_lease)
+#define DRM_IOCTL_MODE_LIST_LESSEES	DRM_IOWR(0xC0, struct drm_mode_list_lessees)
+#define DRM_IOCTL_MODE_GET_LEASE	DRM_IOWR(0xC1, struct drm_mode_get_lease)
+#define DRM_IOCTL_MODE_CHANGE_LEASE	DRM_IOWR(0xC2, struct drm_mode_change_lease)
 
 /**
  * Device specific ioctls should only be in their respective headers
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index ce7efe2e8a5e..e6669ada3b10 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -681,6 +681,84 @@ struct drm_mode_destroy_blob {
 	__u32 blob_id;
 };
 
+/**
+ * Lease mode resources, creating another drm_master.
+ */
+struct drm_mode_create_lease {
+	/** Pointer to array of object ids (__u32) */
+	__u64 object_ids;
+	/** Number of object ids */
+	__u32 object_count;
+	/** flags for new FD (O_CLOEXEC, etc) */
+	__u32 flags;
+	/** whether to hide the leased objects from the lessor */
+	__u32 mask_lease;
+
+	/** Return: unique identifier for lessee. */
+	__u32 lessee_id;
+	/** Return: file descriptor to new drm_master file */
+	__u32 fd;
+};
+
+/**
+ * List lesses from a drm_master
+ */
+struct drm_mode_list_lessees {
+
+	/** Identifier of the lessor's lessee_id (0 for owner) */
+	__u32 lessor_id;
+
+	/** Number of lessees.
+	 * On input, provides length of the array.
+	 * On output, provides total number. No
+	 * more than the input number will be written
+	 * back, so two calls can be used to get
+	 * the size and then the data.
+	 */
+	__u32 count_lessees;
+
+	/** Pointer to lessees.
+	 * pointer to __u64 array of lessee ids
+	 */
+	__u64 lessees_ptr;
+};
+
+/**
+ * Get leased objects for a lessee
+ */
+struct drm_mode_get_lease {
+	/** Identifier of the lessee (0 for owner) */
+	__u32 lessee_id;
+
+	/** Number of leased objects.
+	 * On input, provides length of the array.
+	 * On output, provides total number. No
+	 * more than the input number will be written
+	 * back, so two calls can be used to get
+	 * the size and then the data.
+	 */
+	__u32 count_objects;
+
+	/** Pointer to objects.
+	 * pointer to __u32 array of object ids
+	 */
+	__u64 objects_ptr;
+};
+
+/**
+ * Change resources leased to another drm_master
+ */
+struct drm_mode_change_lease {
+	/** Pointer to array of object ids (__u32) */
+	__u64 object_ids;
+	/** Number of object ids */
+	__u32 object_count;
+	/** unique identifier for lessee. */
+	__u32 lessee_id;
+	/** whether to hide the leased objects from the lessor */
+	__u32 mask_lease;
+};
+
 #if defined(__cplusplus)
 }
 #endif
-- 
2.11.0