[PATCH 3/8] drm: introduce sync objects as sync file objects with no fd (v2.1)

Dave Airlie airlied at gmail.com
Wed Apr 12 04:57:21 UTC 2017


From: Dave Airlie <airlied at redhat.com>

Sync objects are new toplevel drm object, that have the same
semantics as sync_file objects, but without requiring an fd
to be consumed to support them.

This patch just enables the DRM interface to create these
objects, it doesn't actually provide any semaphore objects
or new features.

v2: do get/put on the sync file file to avoid race (Daniel)
v2.1: fix reference counting bug on import (Jason)
cleanup destroy (Jason)
fix a bunch of bugs for the igt test.
restrict semaphore objects for create/and fd conversions.

Reviewed-by: Christian König <christian.koenig at amd.com>
Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 Documentation/gpu/drm-internals.rst |   5 +
 Documentation/gpu/drm-mm.rst        |   6 +
 drivers/gpu/drm/Makefile            |   2 +-
 drivers/gpu/drm/drm_fops.c          |   8 +
 drivers/gpu/drm/drm_internal.h      |  15 ++
 drivers/gpu/drm/drm_ioctl.c         |  14 ++
 drivers/gpu/drm/drm_syncobj.c       | 287 ++++++++++++++++++++++++++++++++++++
 include/drm/drmP.h                  |   5 +
 include/drm/drm_drv.h               |   1 +
 include/uapi/drm/drm.h              |  27 ++++
 10 files changed, 369 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/drm_syncobj.c

diff --git a/Documentation/gpu/drm-internals.rst b/Documentation/gpu/drm-internals.rst
index e35920d..743b751 100644
--- a/Documentation/gpu/drm-internals.rst
+++ b/Documentation/gpu/drm-internals.rst
@@ -98,6 +98,11 @@ DRIVER_ATOMIC
     implement appropriate obj->atomic_get_property() vfuncs for any
     modeset objects with driver specific properties.
 
+DRIVER_SYNCOBJ
+    Driver support sync objects. These are just sync files that don't
+    use a file descriptor. They can be used to implement Vulkan shared
+    semaphores.
+
 Major, Minor and Patchlevel
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst
index f5760b1..28aebe8 100644
--- a/Documentation/gpu/drm-mm.rst
+++ b/Documentation/gpu/drm-mm.rst
@@ -483,3 +483,9 @@ DRM Cache Handling
 
 .. kernel-doc:: drivers/gpu/drm/drm_cache.c
    :export:
+
+DRM Sync Objects
+===========================
+
+.. kernel-doc:: drivers/gpu/drm/drm_syncobj.c
+   :export:
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 3ee9579..b5e565c 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -16,7 +16,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_framebuffer.o drm_connector.o drm_blend.o \
 		drm_encoder.o drm_mode_object.o drm_property.o \
 		drm_plane.o drm_color_mgmt.o drm_print.o \
-		drm_dumb_buffers.o drm_mode_config.o
+		drm_dumb_buffers.o drm_mode_config.o drm_syncobj.o
 
 drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
 drm-$(CONFIG_DRM_VM) += drm_vm.o
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index afdf5b1..9a61df2 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -219,6 +219,9 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_open(dev, priv);
 
+	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		drm_syncobj_open(priv);
+
 	if (drm_core_check_feature(dev, DRIVER_PRIME))
 		drm_prime_init_file_private(&priv->prime);
 
@@ -266,6 +269,8 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
 out_prime_destroy:
 	if (drm_core_check_feature(dev, DRIVER_PRIME))
 		drm_prime_destroy_file_private(&priv->prime);
+	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		drm_syncobj_release(priv);
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_release(dev, priv);
 	put_pid(priv->pid);
@@ -400,6 +405,9 @@ int drm_release(struct inode *inode, struct file *filp)
 		drm_property_destroy_user_blobs(dev, file_priv);
 	}
 
+	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		drm_syncobj_release(file_priv);
+
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_release(dev, file_priv);
 
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index f37388c..70c27a0 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -142,4 +142,19 @@ static inline int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
 {
 	return 0;
 }
+
 #endif
+
+/* drm_syncobj.c */
+void drm_syncobj_open(struct drm_file *file_private);
+void drm_syncobj_release(struct drm_file *file_private);
+int drm_syncobj_create_ioctl(struct drm_device *dev, void *data,
+			     struct drm_file *file_private);
+int drm_syncobj_destroy_ioctl(struct drm_device *dev, void *data,
+			      struct drm_file *file_private);
+int drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
+				   struct drm_file *file_private);
+int drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
+				   struct drm_file *file_private);
+int drm_syncobj_info_ioctl(struct drm_device *dev, void *data,
+			   struct drm_file *file_private);
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index a7c61c2..4a8ed66 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -240,6 +240,9 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
 		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
 		return 0;
+	case DRM_CAP_SYNCOBJ:
+		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);
+		return 0;
 	}
 
 	/* Other caps only work with KMS drivers */
@@ -641,6 +644,17 @@ 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_SYNCOBJ_CREATE, drm_syncobj_create_ioctl,
+		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_DESTROY, drm_syncobj_destroy_ioctl,
+		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD, drm_syncobj_handle_to_fd_ioctl,
+		      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_SYNCOBJ_INFO, drm_syncobj_info_ioctl,
+		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
 };
 
 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
new file mode 100644
index 0000000..4827f90
--- /dev/null
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -0,0 +1,287 @@
+/*
+ * Copyright © 2017 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *
+ */
+
+/**
+ * DOC: Overview
+ *
+ * DRM synchronisation objects (syncobj) are wrappers for sync_file objects,
+ * that don't use fd space, and can be converted to/from sync_file fds.
+ *
+ * Depending on the sync object type, they can expose different sync_file
+ * semantics and restrictions.
+ *
+ * Their primary use-case is to implement Vulkan shared semaphores.
+ */
+
+#include <drm/drmP.h>
+#include <linux/sync_file.h>
+#include "drm_internal.h"
+
+static struct sync_file *drm_syncobj_get(struct drm_file *file_private,
+					 u32 handle)
+{
+	struct sync_file *sync_file;
+
+	spin_lock(&file_private->syncobj_table_lock);
+
+	/* Check if we currently have a reference on the object */
+	sync_file = idr_find(&file_private->syncobj_idr, handle);
+	if (sync_file)
+		get_file(sync_file->file);
+
+	spin_unlock(&file_private->syncobj_table_lock);
+
+	return sync_file;
+}
+
+static int drm_syncobj_create(struct drm_file *file_private,
+			      unsigned type,
+			      unsigned flags, u32 *handle)
+{
+	struct sync_file *sync_file;
+	int ret;
+
+	ret = sync_file_validate_type_flags(type, flags);
+	if (ret)
+		return ret;
+
+	sync_file = sync_file_alloc(type, flags);
+	if (!sync_file)
+		return -ENOMEM;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock(&file_private->syncobj_table_lock);
+	ret = idr_alloc(&file_private->syncobj_idr, sync_file, 1, 0, GFP_NOWAIT);
+	spin_unlock(&file_private->syncobj_table_lock);
+
+	idr_preload_end();
+
+	if (ret < 0) {
+		fput(sync_file->file);
+		return ret;
+	}
+
+	*handle = ret;
+	return 0;
+}
+
+static int drm_syncobj_destroy(struct drm_file *file_private,
+			       u32 handle)
+{
+	struct sync_file *sync_file;
+
+	spin_lock(&file_private->syncobj_table_lock);
+	sync_file = idr_remove(&file_private->syncobj_idr, handle);
+	spin_unlock(&file_private->syncobj_table_lock);
+
+	if (!sync_file)
+		return -EINVAL;
+
+	fput(sync_file->file);
+	return 0;
+}
+
+static int drm_syncobj_handle_to_fd(struct drm_file *file_private,
+				    u32 handle, int *fd)
+{
+	struct sync_file *sync_file = drm_syncobj_get(file_private, handle);
+	int ret;
+	if (!sync_file)
+		return -EINVAL;
+
+	if (sync_file->type != SYNC_FILE_TYPE_SEMAPHORE) {
+		fput(sync_file->file);
+		return -EINVAL;
+	}
+
+	ret = get_unused_fd_flags(O_CLOEXEC);
+	if (ret < 0) {
+		fput(sync_file->file);
+		return ret;
+	}
+	fd_install(ret, sync_file->file);
+	*fd = ret;
+	/* leave reference with fd */
+	return 0;
+}
+
+static int drm_syncobj_fd_to_handle(struct drm_file *file_private,
+				    int fd, u32 *handle)
+{
+	struct sync_file *sync_file = sync_file_fdget(fd);
+	int ret;
+	if (!sync_file)
+		return -EINVAL;
+
+	if (sync_file->type != SYNC_FILE_TYPE_SEMAPHORE) {
+		fput(sync_file->file);
+		return -EINVAL;
+	}
+
+	idr_preload(GFP_KERNEL);
+	spin_lock(&file_private->syncobj_table_lock);
+	ret = idr_alloc(&file_private->syncobj_idr, sync_file, 1, 0, GFP_NOWAIT);
+	spin_unlock(&file_private->syncobj_table_lock);
+	idr_preload_end();
+
+	if (ret < 0) {
+		fput(sync_file->file);
+		return ret;
+	}
+	*handle = ret;
+	return 0;
+}
+
+static int drm_syncobj_info(struct drm_file *file_private,
+			    u32 handle, u32 *type, u32 *flags)
+{
+	struct sync_file *sync_file = drm_syncobj_get(file_private, handle);
+
+	if (!sync_file)
+		return -EINVAL;
+	*type = sync_file->type;
+	*flags = sync_file->flags;
+	fput(sync_file->file);
+	return 0;
+}
+
+/**
+ * drm_syncobj_open - initalizes syncobj file-private structures at devnode open time
+ * @dev: drm_device which is being opened by userspace
+ * @file_private: drm file-private structure to set up
+ *
+ * Called at device open time, sets up the structure for handling refcounting
+ * of sync objects.
+ */
+void
+drm_syncobj_open(struct drm_file *file_private)
+{
+	idr_init(&file_private->syncobj_idr);
+	spin_lock_init(&file_private->syncobj_table_lock);
+}
+
+static int
+drm_syncobj_release_handle(int id, void *ptr, void *data)
+{
+	struct sync_file *sync_file = ptr;
+
+	fput(sync_file->file);
+	return 0;
+}
+
+/**
+ * drm_syncobj_release - release file-private sync object resources
+ * @dev: drm_device which is being closed by userspace
+ * @file_private: drm file-private structure to clean up
+ *
+ * Called at close time when the filp is going away.
+ *
+ * Releases any remaining references on objects by this filp.
+ */
+void
+drm_syncobj_release(struct drm_file *file_private)
+{
+	idr_for_each(&file_private->syncobj_idr,
+		     &drm_syncobj_release_handle, file_private);
+	idr_destroy(&file_private->syncobj_idr);
+}
+
+int
+drm_syncobj_create_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *file_private)
+{
+	struct drm_syncobj_create_info *args = data;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -ENODEV;
+
+	/* make sure padding is empty */
+	if (args->pad)
+		return -EINVAL;
+
+	/* only allow sync objects for now */
+	if (args->type != SYNC_FILE_TYPE_SEMAPHORE)
+		return -EINVAL;
+	return drm_syncobj_create(file_private, args->type,
+				 args->flags, &args->handle);
+}
+
+int
+drm_syncobj_destroy_ioctl(struct drm_device *dev, void *data,
+			  struct drm_file *file_private)
+{
+	struct drm_syncobj_destroy *args = data;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -ENODEV;
+
+	/* make sure padding is empty */
+	if (args->pad)
+		return -EINVAL;
+	return drm_syncobj_destroy(file_private, args->handle);
+}
+
+int
+drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
+				   struct drm_file *file_private)
+{
+	struct drm_syncobj_handle *args = data;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -ENODEV;
+
+	return drm_syncobj_handle_to_fd(file_private, args->handle,
+					&args->fd);
+}
+
+int
+drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
+				   struct drm_file *file_private)
+{
+	struct drm_syncobj_handle *args = data;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -ENODEV;
+
+	return drm_syncobj_fd_to_handle(file_private, args->fd,
+					&args->handle);
+}
+
+int
+drm_syncobj_info_ioctl(struct drm_device *dev, void *data,
+		       struct drm_file *file_private)
+{
+	struct drm_syncobj_create_info *args = data;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -ENODEV;
+
+	/* make sure padding is empty */
+	if (args->pad)
+		return -EINVAL;
+	return drm_syncobj_info(file_private, args->handle,
+				&args->type, &args->flags);
+}
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 6105c05..1d48f6f 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -405,6 +405,11 @@ struct drm_file {
 	/** Lock for synchronization of access to object_idr. */
 	spinlock_t table_lock;
 
+	/** Mapping of sync object handles to object pointers. */
+	struct idr syncobj_idr;
+	/** Lock for synchronization of access to syncobj_idr. */
+	spinlock_t syncobj_table_lock;
+
 	struct file *filp;
 	void *driver_priv;
 
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 5699f42..48ff06b 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -53,6 +53,7 @@ struct drm_mode_create_dumb;
 #define DRIVER_RENDER			0x8000
 #define DRIVER_ATOMIC			0x10000
 #define DRIVER_KMS_LEGACY_CONTEXT	0x20000
+#define DRIVER_SYNCOBJ                  0x40000
 
 /**
  * struct drm_driver - DRM driver structure
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index b2c5284..f2d3f06 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -647,6 +647,7 @@ struct drm_gem_open {
 #define DRM_CAP_CURSOR_HEIGHT		0x9
 #define DRM_CAP_ADDFB2_MODIFIERS	0x10
 #define DRM_CAP_PAGE_FLIP_TARGET	0x11
+#define DRM_CAP_SYNCOBJ		0x13
 
 /** DRM_IOCTL_GET_CAP ioctl argument type */
 struct drm_get_cap {
@@ -696,6 +697,26 @@ struct drm_prime_handle {
 	__s32 fd;
 };
 
+struct drm_syncobj_create_info {
+	__u32 handle;
+	__u32 type;
+	__u32 flags;
+	__u32 pad;
+};
+
+struct drm_syncobj_destroy {
+	__u32 handle;
+	__u32 pad;
+};
+
+struct drm_syncobj_handle {
+	__u32 handle;
+	/** Flags.. only applicable for handle->fd */
+	__u32 flags;
+
+	__s32 fd;
+};
+
 #if defined(__cplusplus)
 }
 #endif
@@ -814,6 +835,12 @@ extern "C" {
 #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_SYNCOBJ_CREATE	DRM_IOWR(0xBF, struct drm_syncobj_create_info)
+#define DRM_IOCTL_SYNCOBJ_DESTROY	DRM_IOWR(0xC0, struct drm_syncobj_destroy)
+#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_SYNCOBJ_INFO		DRM_IOWR(0xC3, struct drm_syncobj_create_info)
+
 /**
  * Device specific ioctls should only be in their respective headers
  * The device specific ioctl range is from 0x40 to 0x9f.
-- 
2.9.3



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