[PATCH 6/6] drm: Add four ioctls for managing drm mode object leases [v4]

From: Keith Packard
Date: Thu Oct 05 2017 - 02:20:50 EST


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 for a master file

drm_mode_get_lease

List the leased objects for a master file

drm_mode_revoke_lease

Erase the set of objects managed by a lease.

This should suffice to at least create and query leases.

Changes for v2 as suggested by Daniel Vetter <daniel.vetter@xxxxxxxx>:

* query ioctls only query the master associated with
the provided file.

* 'mask_lease' value has been removed

* change ioctl has been removed.

Changes for v3 suggested in part by Dave Airlie <airlied@xxxxxxxxx>

* Add revoke ioctl.

Changes for v3 suggested by Dave Airlie <airlied@xxxxxxxxx>

* Expand on the comment about the magic use of &drm_lease_idr_object
* Pad lease ioctl structures to align on 64-bit boundaries

Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
drivers/gpu/drm/drm_ioctl.c | 4 +
drivers/gpu/drm/drm_lease.c | 277 ++++++++++++++++++++++++++++++++++++++++++++
include/drm/drm_lease.h | 12 ++
include/uapi/drm/drm.h | 5 +
include/uapi/drm/drm_mode.h | 66 +++++++++++
5 files changed, 364 insertions(+)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 7d0e481c5729..3ed76220b4b1 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -657,6 +657,10 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
DRM_UNLOCKED|DRM_RENDER_ALLOW),
DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE, drm_syncobj_fd_to_handle_ioctl,
DRM_UNLOCKED|DRM_RENDER_ALLOW),
+ DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE, drm_mode_create_lease_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+ DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, drm_mode_list_lessees_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+ DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+ DRM_IOCTL_DEF(DRM_IOCTL_MODE_REVOKE_LEASE, drm_mode_revoke_lease_ioctl, DRM_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 2ac404264d75..e885ea76de8f 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -23,6 +23,8 @@
#define drm_for_each_lessee(lessee, lessor) \
list_for_each_entry((lessee), &(lessor)->lessees, lessee_list)

+static uint64_t drm_lease_idr_object;
+
/**
* drm_lease_owner - return ancestor owner drm_master
* @master: drm_master somewhere within tree of lessees and lessors
@@ -377,3 +379,278 @@ void _drm_lease_revoke(struct drm_master *top)
}
}
}
+
+/**
+ * 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;
+
+ /* Do not allow sub-leases */
+ if (lessor->lessor)
+ return -EINVAL;
+
+ object_count = cl->object_count;
+ idr_init(&leases);
+
+ /* Allocate a file descriptor for the lease */
+ 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 out_leases;
+ }
+ DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id);
+
+ /*
+ * We're using an IDR to hold the set of leased
+ * objects, but we don't need to point at the object's
+ * data structure from the lease as the main crtc_idr
+ * will be used to actually find that. Instead, all we
+ * really want is a 'leased/not-leased' result, for
+ * which any non-NULL pointer will work fine.
+ */
+ ret = idr_alloc(&leases, &drm_lease_idr_object , 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 out_leases;
+ }
+ }
+
+ mutex_lock(&dev->master_mutex);
+
+ DRM_DEBUG_LEASE("Creating lease\n");
+ lessee = drm_lease_create(lessor, &leases);
+
+ if (IS_ERR(lessee)) {
+ ret = PTR_ERR(lessee);
+ mutex_unlock(&dev->master_mutex);
+ goto out_leases;
+ }
+
+ /* 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));
+ mutex_unlock(&dev->master_mutex);
+
+ if (IS_ERR(lessee_file)) {
+ ret = PTR_ERR(lessee_file);
+ goto out_lessee;
+ }
+
+ /* 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 out_lessee_file;
+
+ 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;
+
+ DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n");
+ return 0;
+
+out_lessee_file:
+ fput(lessee_file);
+
+out_lessee:
+ drm_master_put(&lessee);
+
+out_leases:
+ idr_destroy(&leases);
+ put_unused_fd(fd);
+
+ DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
+ return ret;
+}
+
+/**
+ * drm_mode_list_lessees_ioctl - list lessee ids
+ * @dev: the drm device
+ * @data: pointer to struct drm_mode_list_lessees
+ * @lessor_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 *lessor_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 = lessor_priv->master, *lessee;
+ int count;
+ int ret = 0;
+
+ DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id);
+
+ mutex_lock(&dev->master_mutex);
+
+ count = 0;
+ drm_for_each_lessee(lessee, lessor) {
+ /* Only list un-revoked leases */
+ if (!idr_is_empty(&lessee->leases)) {
+ 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;
+
+ 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_get_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 *lessee_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 = lessee_priv->master;
+ struct idr *object_idr;
+ int count;
+ void *entry;
+ int object;
+ int ret = 0;
+
+ DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id);
+
+ mutex_lock(&dev->master_mutex);
+
+ if (lessee->lessor == NULL)
+ /* owner can use all objects */
+ object_idr = &lessee->dev->mode_config.crtc_idr;
+ else
+ /* lessee can only use allowed object */
+ 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;
+
+ mutex_unlock(&dev->master_mutex);
+
+ return ret;
+}
+
+/**
+ * drm_mode_revoke_lease_ioctl - revoke lease
+ * @dev: the drm device
+ * @data: pointer to struct drm_mode_revoke_lease
+ * @file_priv: the file being manipulated
+ *
+ * This removes all of the objects from the lease without
+ * actually getting rid of the lease itself; that way all
+ * references to it still work correctly
+ */
+int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
+ void *data, struct drm_file *lessor_priv)
+{
+ struct drm_mode_revoke_lease *arg = data;
+ struct drm_master *lessor = lessor_priv->master;
+ struct drm_master *lessee;
+ int ret = 0;
+
+ DRM_DEBUG_LEASE("revoke lease for %d\n", arg->lessee_id);
+
+ mutex_lock(&dev->master_mutex);
+
+ lessee = _drm_find_lessee(lessor, arg->lessee_id);
+
+ /* No such lessee */
+ if (!lessee) {
+ ret = -ENOENT;
+ goto fail;
+ }
+
+ /* Lease is not held by lessor */
+ if (lessee->lessor != lessor) {
+ ret = -EACCES;
+ goto fail;
+ }
+
+ _drm_lease_revoke(lessee);
+
+fail:
+ mutex_unlock(&dev->master_mutex);
+
+ return ret;
+}
diff --git a/include/drm/drm_lease.h b/include/drm/drm_lease.h
index a49667db1d6d..53ffcee2617e 100644
--- a/include/drm/drm_lease.h
+++ b/include/drm/drm_lease.h
@@ -33,4 +33,16 @@ uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs);

uint32_t drm_lease_filter_encoders(struct drm_file *file_priv, 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_revoke_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 101593ab10ac..dd350bf0ad75 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -841,6 +841,11 @@ extern "C" {
#define DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD DRM_IOWR(0xC1, struct drm_syncobj_handle)
#define DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE DRM_IOWR(0xC2, struct drm_syncobj_handle)

+#define DRM_IOCTL_MODE_CREATE_LEASE DRM_IOWR(0xC3, struct drm_mode_create_lease)
+#define DRM_IOCTL_MODE_LIST_LESSEES DRM_IOWR(0xC4, struct drm_mode_list_lessees)
+#define DRM_IOCTL_MODE_GET_LEASE DRM_IOWR(0xC5, struct drm_mode_get_lease)
+#define DRM_IOCTL_MODE_REVOKE_LEASE DRM_IOWR(0xC6, struct drm_mode_revoke_lease)
+
/**
* Device specific ioctls should only be in their respective headers
* The device specific ioctl range is from 0x40 to 0x9f.
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 403339f98a92..5964f25fa88e 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -732,6 +732,72 @@ 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;
+
+ /** 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 {
+ /** 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;
+ __u32 pad;
+
+ /** Pointer to lessees.
+ * pointer to __u64 array of lessee ids
+ */
+ __u64 lessees_ptr;
+};
+
+/**
+ * Get leased objects
+ */
+struct drm_mode_get_lease {
+ /** 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;
+ __u32 pad;
+
+ /** Pointer to objects.
+ * pointer to __u32 array of object ids
+ */
+ __u64 objects_ptr;
+};
+
+/**
+ * Revoke lease
+ */
+struct drm_mode_revoke_lease {
+ /** Unique ID of lessee
+ */
+ __u32 lessee_id;
+};
+
#if defined(__cplusplus)
}
#endif
--
2.13.3