[PATCH v8 0/3] drm: add explict fencing

[PATCH v8 0/3] drm: add explict fencing

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Hi,

Another iteration after Brian comments. Please refer to the cover letter[1] in
a previous version to check for more details.

The changes since the last version can be seen in commit message on each patch.

Robert Foss managed to port Android's drm_hwcomposer to the new HWC2 API and
added support to fences. Current patches can be seen here:

https://git.collabora.com/cgit/user/robertfoss/drm_hwcomposer.git/log/?h=hwc2_fence_v1

He ran AOSP on top of padovan/fences kernel branch with full fence support on
qemu/virgl and msm db410c. That means we already have a working open source
userspace using the explicit fencing implementation.

Also i-g-t testing are available with all tests suggested in v7 included:

https://git.collabora.com/cgit/user/padovan/intel-gpu-tools.git/log/

Please review!

Gustavo

[1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1253822.html

---
Gustavo Padovan (3):
  drm/fence: add in-fences support
  drm/fence: add fence timeline to drm_crtc
  drm/fence: add out-fences support

 drivers/gpu/drm/Kconfig             |   1 +
 drivers/gpu/drm/drm_atomic.c        | 257 +++++++++++++++++++++++++++++-------
 drivers/gpu/drm/drm_atomic_helper.c |   5 +
 drivers/gpu/drm/drm_crtc.c          |  45 +++++++
 drivers/gpu/drm/drm_plane.c         |   1 +
 include/drm/drm_atomic.h            |   1 +
 include/drm/drm_crtc.h              |  56 ++++++++
 7 files changed, 321 insertions(+), 45 deletions(-)

-- 
2.5.5

[PATCH v8 1/3] drm/fence: add in-fences support

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

There is now a new property called IN_FENCE_FD attached to every plane
state that receives sync_file fds from userspace via the atomic commit
IOCTL.

The fd is then translated to a fence (that may be a fence_array
subclass or just a normal fence) and then used by DRM to fence_wait() for
all fences in the sync_file to signal. So it only commits when all
framebuffers are ready to scanout.

v2: Comments by Daniel Vetter:
	- remove set state->fence = NULL in destroy phase
	- accept fence -1 as valid and just return 0
	- do not call fence_get() - sync_file_fences_get() already calls it
	- fence_put() if state->fence is already set, in case userspace
	set the property more than once.

v3: WARN_ON if fence is set but state has no FB

v4: Comment from Maarten Lankhorst
	- allow set fence with no related fb

v5: rename FENCE_FD to IN_FENCE_FD

v6: Comments by Daniel Vetter:
	- rename plane_state->in_fence back to "fence"
	- re-introduce WARN_ON if fence set but no fb

     - rebase after fence -> dma_fence rename

v7: Comments by Brian Starkey
	- set state->fence to NULL when duplicating the state
	- fail if IN_FENCE_FD was already set

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
---
 drivers/gpu/drm/Kconfig             |  1 +
 drivers/gpu/drm/drm_atomic.c        | 14 ++++++++++++++
 drivers/gpu/drm/drm_atomic_helper.c |  5 +++++
 drivers/gpu/drm/drm_crtc.c          |  6 ++++++
 drivers/gpu/drm/drm_plane.c         |  1 +
 include/drm/drm_crtc.h              |  5 +++++
 6 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 25e8e37..360cb92 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -12,6 +12,7 @@ menuconfig DRM
 	select I2C
 	select I2C_ALGOBIT
 	select DMA_SHARED_BUFFER
+	select SYNC_FILE
 	help
 	  Kernel-level support for the Direct Rendering Infrastructure (DRI)
 	  introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index b096c16..8e26ad1 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -31,6 +31,7 @@
 #include <drm/drm_mode.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_print.h>
+#include <linux/sync_file.h>
 
 #include "drm_crtc_internal.h"
 
@@ -709,6 +710,17 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
 		drm_atomic_set_fb_for_plane(state, fb);
 		if (fb)
 			drm_framebuffer_unreference(fb);
+	} else if (property == config->prop_in_fence_fd) {
+		if (state->fence)
+			return -EINVAL;
+
+		if (U642I64(val) == -1)
+			return 0;
+
+		state->fence = sync_file_get_fence(val);
+		if (!state->fence)
+			return -EINVAL;
+
 	} else if (property == config->prop_crtc_id) {
 		struct drm_crtc *crtc = drm_crtc_find(dev, val);
 		return drm_atomic_set_crtc_for_plane(state, crtc);
@@ -770,6 +782,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
 
 	if (property == config->prop_fb_id) {
 		*val = (state->fb) ? state->fb->base.id : 0;
+	} else if (property == config->prop_in_fence_fd) {
+		*val = -1;
 	} else if (property == config->prop_crtc_id) {
 		*val = (state->crtc) ? state->crtc->base.id : 0;
 	} else if (property == config->prop_crtc_x) {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 75ad01d..caed870 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3076,6 +3076,8 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
 
 	if (state->fb)
 		drm_framebuffer_reference(state->fb);
+
+	state->fence = NULL;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
 
@@ -3114,6 +3116,9 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
 {
 	if (state->fb)
 		drm_framebuffer_unreference(state->fb);
+
+	if (state->fence)
+		dma_fence_put(state->fence);
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);
 
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index ce274ed..154e040 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -397,6 +397,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.prop_fb_id = prop;
 
+	prop = drm_property_create_signed_range(dev, DRM_MODE_PROP_ATOMIC,
+			"IN_FENCE_FD", -1, INT_MAX);
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.prop_in_fence_fd = prop;
+
 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
 	if (!prop)
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 249c0ae..3957ef8 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -137,6 +137,7 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
 
 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
 		drm_object_attach_property(&plane->base, config->prop_fb_id, 0);
+		drm_object_attach_property(&plane->base, config->prop_in_fence_fd, -1);
 		drm_object_attach_property(&plane->base, config->prop_crtc_id, 0);
 		drm_object_attach_property(&plane->base, config->prop_crtc_x, 0);
 		drm_object_attach_property(&plane->base, config->prop_crtc_y, 0);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 8cca2a8..11780a9 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1214,6 +1214,11 @@ struct drm_mode_config {
 	 */
 	struct drm_property *prop_fb_id;
 	/**
+	 * @prop_in_fence_fd: Sync File fd representing the incoming fences
+	 * for a Plane.
+	 */
+	struct drm_property *prop_in_fence_fd;
+	/**
 	 * @prop_crtc_id: Default atomic plane property to specify the
 	 * &drm_crtc.
 	 */
-- 
2.5.5

Re: [PATCH v8 1/3] drm/fence: add in-fences support

[Sean Paul]

On Fri, Nov 11, 2016 at 9:15 AM, Gustavo Padovan <gustavo@padovan.org> wrote:
> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
> There is now a new property called IN_FENCE_FD attached to every plane
> state that receives sync_file fds from userspace via the atomic commit
> IOCTL.
>
> The fd is then translated to a fence (that may be a fence_array
> subclass or just a normal fence) and then used by DRM to fence_wait() for
> all fences in the sync_file to signal. So it only commits when all
> framebuffers are ready to scanout.
>
> v2: Comments by Daniel Vetter:
>         - remove set state->fence = NULL in destroy phase
>         - accept fence -1 as valid and just return 0
>         - do not call fence_get() - sync_file_fences_get() already calls it
>         - fence_put() if state->fence is already set, in case userspace
>         set the property more than once.
>
> v3: WARN_ON if fence is set but state has no FB
>
> v4: Comment from Maarten Lankhorst
>         - allow set fence with no related fb
>
> v5: rename FENCE_FD to IN_FENCE_FD
>
> v6: Comments by Daniel Vetter:
>         - rename plane_state->in_fence back to "fence"
>         - re-introduce WARN_ON if fence set but no fb
>
>      - rebase after fence -> dma_fence rename
>
> v7: Comments by Brian Starkey
>         - set state->fence to NULL when duplicating the state
>         - fail if IN_FENCE_FD was already set
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> Reviewed-by: Brian Starkey <brian.starkey@arm.com>

Reviewed-by: Sean Paul <seanpaul@chromium.org>

> ---
>  drivers/gpu/drm/Kconfig             |  1 +
>  drivers/gpu/drm/drm_atomic.c        | 14 ++++++++++++++
>  drivers/gpu/drm/drm_atomic_helper.c |  5 +++++
>  drivers/gpu/drm/drm_crtc.c          |  6 ++++++
>  drivers/gpu/drm/drm_plane.c         |  1 +
>  include/drm/drm_crtc.h              |  5 +++++
>  6 files changed, 32 insertions(+)
>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 25e8e37..360cb92 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -12,6 +12,7 @@ menuconfig DRM
>         select I2C
>         select I2C_ALGOBIT
>         select DMA_SHARED_BUFFER
> +       select SYNC_FILE
>         help
>           Kernel-level support for the Direct Rendering Infrastructure (DRI)
>           introduced in XFree86 4.0. If you say Y here, you need to select
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index b096c16..8e26ad1 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -31,6 +31,7 @@
>  #include <drm/drm_mode.h>
>  #include <drm/drm_plane_helper.h>
>  #include <drm/drm_print.h>
> +#include <linux/sync_file.h>
>
>  #include "drm_crtc_internal.h"
>
> @@ -709,6 +710,17 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
>                 drm_atomic_set_fb_for_plane(state, fb);
>                 if (fb)
>                         drm_framebuffer_unreference(fb);
> +       } else if (property == config->prop_in_fence_fd) {
> +               if (state->fence)
> +                       return -EINVAL;
> +
> +               if (U642I64(val) == -1)
> +                       return 0;
> +
> +               state->fence = sync_file_get_fence(val);
> +               if (!state->fence)
> +                       return -EINVAL;
> +
>         } else if (property == config->prop_crtc_id) {
>                 struct drm_crtc *crtc = drm_crtc_find(dev, val);
>                 return drm_atomic_set_crtc_for_plane(state, crtc);
> @@ -770,6 +782,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
>
>         if (property == config->prop_fb_id) {
>                 *val = (state->fb) ? state->fb->base.id : 0;
> +       } else if (property == config->prop_in_fence_fd) {
> +               *val = -1;
>         } else if (property == config->prop_crtc_id) {
>                 *val = (state->crtc) ? state->crtc->base.id : 0;
>         } else if (property == config->prop_crtc_x) {
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 75ad01d..caed870 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -3076,6 +3076,8 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
>
>         if (state->fb)
>                 drm_framebuffer_reference(state->fb);
> +
> +       state->fence = NULL;
>  }
>  EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
>
> @@ -3114,6 +3116,9 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
>  {
>         if (state->fb)
>                 drm_framebuffer_unreference(state->fb);
> +
> +       if (state->fence)
> +               dma_fence_put(state->fence);
>  }
>  EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index ce274ed..154e040 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -397,6 +397,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>                 return -ENOMEM;
>         dev->mode_config.prop_fb_id = prop;
>
> +       prop = drm_property_create_signed_range(dev, DRM_MODE_PROP_ATOMIC,
> +                       "IN_FENCE_FD", -1, INT_MAX);
> +       if (!prop)
> +               return -ENOMEM;
> +       dev->mode_config.prop_in_fence_fd = prop;
> +
>         prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
>                         "CRTC_ID", DRM_MODE_OBJECT_CRTC);
>         if (!prop)
> diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> index 249c0ae..3957ef8 100644
> --- a/drivers/gpu/drm/drm_plane.c
> +++ b/drivers/gpu/drm/drm_plane.c
> @@ -137,6 +137,7 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
>
>         if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
>                 drm_object_attach_property(&plane->base, config->prop_fb_id, 0);
> +               drm_object_attach_property(&plane->base, config->prop_in_fence_fd, -1);
>                 drm_object_attach_property(&plane->base, config->prop_crtc_id, 0);
>                 drm_object_attach_property(&plane->base, config->prop_crtc_x, 0);
>                 drm_object_attach_property(&plane->base, config->prop_crtc_y, 0);
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 8cca2a8..11780a9 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1214,6 +1214,11 @@ struct drm_mode_config {
>          */
>         struct drm_property *prop_fb_id;
>         /**
> +        * @prop_in_fence_fd: Sync File fd representing the incoming fences
> +        * for a Plane.
> +        */
> +       struct drm_property *prop_in_fence_fd;
> +       /**
>          * @prop_crtc_id: Default atomic plane property to specify the
>          * &drm_crtc.
>          */
> --
> 2.5.5
>

[PATCH v8 2/3] drm/fence: add fence timeline to drm_crtc

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Create one timeline context for each CRTC to be able to handle out-fences
and signal them. It adds a few members to struct drm_crtc: fence_context,
where we store the context we get from fence_context_alloc(), the
fence seqno and the fence lock, that we pass in fence_init() to be
used by the fence.

v2: Comment by Daniel Stone:
	- add BUG_ON() to fence_to_crtc() macro

v3: Comment by Ville Syrjälä
	- Use more meaningful name as crtc timeline name

v4: Comments by Brian Starkey
	- Use even more meaninful name for the crtc timeline
	- add doc for timeline_name
    Comment by Daniel Vetter
	- use in-line style for comments

    - rebase after fence -> dma_fence rename

v5: Comment by Daniel Vetter
	- Add doc for drm_crtc_fence_ops

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/drm_crtc.c | 31 +++++++++++++++++++++++++++++++
 include/drm/drm_crtc.h     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 154e040..9b9881b 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -165,6 +165,32 @@ static void drm_crtc_crc_fini(struct drm_crtc *crtc)
 #endif
 }
 
+static const char *drm_crtc_fence_get_driver_name(struct dma_fence *fence)
+{
+	struct drm_crtc *crtc = fence_to_crtc(fence);
+
+	return crtc->dev->driver->name;
+}
+
+static const char *drm_crtc_fence_get_timeline_name(struct dma_fence *fence)
+{
+	struct drm_crtc *crtc = fence_to_crtc(fence);
+
+	return crtc->timeline_name;
+}
+
+static bool drm_crtc_fence_enable_signaling(struct dma_fence *fence)
+{
+	return true;
+}
+
+const struct dma_fence_ops drm_crtc_fence_ops = {
+	.get_driver_name = drm_crtc_fence_get_driver_name,
+	.get_timeline_name = drm_crtc_fence_get_timeline_name,
+	.enable_signaling = drm_crtc_fence_enable_signaling,
+	.wait = dma_fence_default_wait,
+};
+
 /**
  * drm_crtc_init_with_planes - Initialise a new CRTC object with
  *    specified primary and cursor planes.
@@ -222,6 +248,11 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 		return -ENOMEM;
 	}
 
+	crtc->fence_context = dma_fence_context_alloc(1);
+	spin_lock_init(&crtc->fence_lock);
+	snprintf(crtc->timeline_name, sizeof(crtc->timeline_name),
+		 "CRTC:%d-%s", crtc->base.id, crtc->name);
+
 	crtc->base.properties = &crtc->properties;
 
 	list_add_tail(&crtc->head, &config->crtc_list);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 11780a9..0870de1 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -32,6 +32,8 @@
 #include <linux/fb.h>
 #include <linux/hdmi.h>
 #include <linux/media-bus-format.h>
+#include <linux/srcu.h>
+#include <linux/dma-fence.h>
 #include <uapi/drm/drm_mode.h>
 #include <uapi/drm/drm_fourcc.h>
 #include <drm/drm_modeset_lock.h>
@@ -739,9 +741,52 @@ struct drm_crtc {
 	 */
 	struct drm_crtc_crc crc;
 #endif
+
+	/**
+	 * @fence_context:
+	 *
+	 * timeline context used for fence operations.
+	 */
+	unsigned int fence_context;
+
+	/**
+	 * @fence_lock:
+	 *
+	 * spinlock to protect the fences in the fence_context.
+	 */
+
+	spinlock_t fence_lock;
+	/**
+	 * @fence_seqno:
+	 *
+	 * Seqno variable used as monotonic counter for the fences
+	 * created on the CRTC's timeline.
+	 */
+	unsigned long fence_seqno;
+
+	/**
+	 * @timeline_name:
+	 *
+	 * The name of the CRTC's fence timeline.
+	 */
+	char timeline_name[32];
 };
 
 /**
+ * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
+ *
+ * It contains the dma_fence_ops that should be called by the dma_fence
+ * code. CRTC core should use this ops when initializing fences.
+ */
+extern const struct dma_fence_ops drm_crtc_fence_ops;
+
+static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
+{
+	BUG_ON(fence->ops != &drm_crtc_fence_ops);
+	return container_of(fence->lock, struct drm_crtc, fence_lock);
+}
+
+/**
  * struct drm_mode_set - new values for a CRTC config change
  * @fb: framebuffer to use for new config
  * @crtc: CRTC whose configuration we're about to change
-- 
2.5.5

[PATCH v8 3/3] drm/fence: add out-fences support

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Support DRM out-fences by creating a sync_file with a fence for each CRTC
that sets the OUT_FENCE_PTR property.

We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
the sync_file fd back to userspace.

The sync_file and fd are allocated/created before commit, but the
fd_install operation only happens after we know that commit succeed.

v2: Comment by Rob Clark:
	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.

    Comment by Daniel Vetter:
	- Add clean up code for out_fences

v3: Comments by Daniel Vetter:
	- create DRM_MODE_ATOMIC_EVENT_MASK
	- userspace should fill out_fences_ptr with the crtc_ids for which
	it wants fences back.

v4: Create OUT_FENCE_PTR properties and remove old approach.

v5: Comments by Brian Starkey:
	- Remove extra fence_get() in atomic_ioctl()
	- Check ret before iterating on the crtc_state
	- check ret before fd_install
	- set fence_state to NULL at the beginning
	- check fence_state->out_fence_ptr before put_user()
	- change order of fput() and put_unused_fd() on failure

     - Add access_ok() check to the out_fence_ptr received
     - Rebase after fence -> dma_fence rename
     - Store out_fence_ptr in the drm_atomic_state
     - Split crtc_setup_out_fence()
     - return -1 as out_fence with TEST_ONLY flag

v6: Comments by Daniel Vetter
	- Add prepare/unprepare_crtc_signaling()
	- move struct drm_out_fence_state to drm_atomic.c
	- mark get_crtc_fence() as static

    Comments by Brian Starkey
	- proper set fence_ptr fence_state array
	- isolate fence_idx increment

    - improve error handling

v7: Comments by Daniel Vetter
	- remove prefix from internal functions
	- make out_fence_ptr an s64 pointer
	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
	- fix doc issues
	- filter out OUT_FENCE_PTR == NULL and do not fail in this case
	- add complete_crtc_signalling()
	- krealloc fence_state on demand

    Comment by Brian Starkey
	- remove unused crtc_state arg from get_out_fence()

v8: Comment by Brian Starkey
	- cancel events before check for !fence_state
	- convert a few lefovers u64 types for out_fence_ptr
	- fix memleak by assign fence_state earlier after realloc
	- proper accout num_fences in case of error

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
 drivers/gpu/drm/drm_atomic.c | 243 +++++++++++++++++++++++++++++++++++--------
 drivers/gpu/drm/drm_crtc.c   |   8 ++
 include/drm/drm_atomic.h     |   1 +
 include/drm/drm_crtc.h       |   6 ++
 4 files changed, 213 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 8e26ad1..34cdc6e 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_atomic_get_crtc_state);
 
+static void set_out_fence_for_crtc(struct drm_atomic_state *state,
+				   struct drm_crtc *crtc, s64 __user *fence_ptr)
+{
+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
+}
+
+static s64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
+					   struct drm_crtc *crtc)
+{
+	s64 __user *fence_ptr;
+
+	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
+
+	return fence_ptr;
+}
+
 /**
  * drm_atomic_set_mode_for_crtc - set mode for CRTC
  * @state: the CRTC whose incoming state to update
@@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					&replaced);
 		state->color_mgmt_changed |= replaced;
 		return ret;
+	} else if (property == config->prop_out_fence_ptr) {
+		s64 __user *fence_ptr = u64_to_user_ptr(val);
+
+		if (!fence_ptr)
+			return 0;
+
+		if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
+			return -EFAULT;
+
+		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
 	} else if (crtc->funcs->atomic_set_property)
 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
 	else
@@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
 		*val = (state->ctm) ? state->ctm->base.id : 0;
 	else if (property == config->gamma_lut_property)
 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
+	else if (property == config->prop_out_fence_ptr)
+		*val = 0;
 	else if (crtc->funcs->atomic_get_property)
 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
 	else
@@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
  */
 
 static struct drm_pending_vblank_event *create_vblank_event(
-		struct drm_device *dev, struct drm_file *file_priv,
-		struct dma_fence *fence, uint64_t user_data)
+		struct drm_device *dev, uint64_t user_data)
 {
 	struct drm_pending_vblank_event *e = NULL;
-	int ret;
 
 	e = kzalloc(sizeof *e, GFP_KERNEL);
 	if (!e)
@@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
 	e->event.base.length = sizeof(e->event);
 	e->event.user_data = user_data;
 
-	if (file_priv) {
-		ret = drm_event_reserve_init(dev, file_priv, &e->base,
-					     &e->event.base);
-		if (ret) {
-			kfree(e);
-			return NULL;
-		}
-	}
-
-	e->base.fence = fence;
-
 	return e;
 }
 
@@ -1788,6 +1804,167 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_clean_old_fb);
 
+static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
+{
+	struct dma_fence *fence;
+
+	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+	if (!fence)
+		return NULL;
+
+	dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
+		       crtc->fence_context, ++crtc->fence_seqno);
+
+	return fence;
+}
+
+struct drm_out_fence_state {
+	s64 __user *out_fence_ptr;
+	struct sync_file *sync_file;
+	int fd;
+};
+
+static int setup_out_fence(struct drm_out_fence_state *fence_state,
+			   struct dma_fence *fence)
+{
+	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fence_state->fd < 0)
+		return fence_state->fd;
+
+	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
+		return -EFAULT;
+
+	fence_state->sync_file = sync_file_create(fence);
+	if(!fence_state->sync_file)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int prepare_crtc_signaling(struct drm_device *dev,
+				  struct drm_atomic_state *state,
+				  struct drm_mode_atomic *arg,
+				  struct drm_file *file_priv,
+				  struct drm_out_fence_state **fence_state,
+				  unsigned int *num_fences)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i, ret;
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		u64 __user *fence_ptr;
+
+		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
+
+		if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) {
+			if (put_user(-1, fence_ptr))
+				return -EFAULT;
+
+			continue;
+		}
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
+			struct drm_pending_vblank_event *e;
+
+			e = create_vblank_event(dev, arg->user_data);
+			if (!e)
+				return -ENOMEM;
+
+			crtc_state->event = e;
+		}
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
+			struct drm_pending_vblank_event *e = crtc_state->event;
+
+			if (!file_priv)
+				continue;
+
+			ret = drm_event_reserve_init(dev, file_priv, &e->base,
+						     &e->event.base);
+			if (ret) {
+				kfree(e);
+				crtc_state->event = NULL;
+				return ret;
+			}
+		}
+
+		if (fence_ptr) {
+			struct dma_fence *fence;
+			struct drm_out_fence_state *f;
+
+			f = krealloc(*fence_state, sizeof(**fence_state) *
+				     (*num_fences + 1), GFP_KERNEL);
+			if (!f)
+				return -ENOMEM;
+
+			f[*num_fences].out_fence_ptr = fence_ptr;
+			*fence_state = f;
+
+			fence = get_crtc_fence(crtc);
+			if (!fence) {
+				(*num_fences)++;
+				return -ENOMEM;
+			}
+
+			ret = setup_out_fence(&f[(*num_fences)++], fence);
+			if (ret) {
+				dma_fence_put(fence);
+				return ret;
+			}
+
+			crtc_state->event->base.fence = fence;
+
+		}
+	}
+
+	return 0;
+}
+
+static void complete_crtc_signaling(struct drm_device *dev,
+				     struct drm_atomic_state *state,
+				     struct drm_out_fence_state *fence_state,
+				     unsigned int num_fences, int ret)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i;
+
+	if (!ret) {
+		for (i = 0; i < num_fences; i++)
+			fd_install(fence_state[i].fd,
+				   fence_state[i].sync_file->file);
+		return;
+	}
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		/*
+		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
+		 * exclusive, if they weren't, this code should be
+		 * called on success for TEST_ONLY too.
+		 */
+		if (crtc_state->event)
+			drm_event_cancel_free(dev, &crtc_state->event->base);
+	}
+
+	if (!fence_state)
+		return;
+
+	for (i = 0; i < num_fences; i++) {
+		if (fence_state[i].sync_file)
+			fput(fence_state[i].sync_file->file);
+		if (fence_state[i].fd >= 0)
+			put_unused_fd(fence_state[i].fd);
+
+		/* If this fails log error to the user */
+		if (fence_state[i].out_fence_ptr &&
+		    put_user(-1, fence_state[i].out_fence_ptr))
+			DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
+	}
+
+	kfree(fence_state);
+}
+
 int drm_mode_atomic_ioctl(struct drm_device *dev,
 			  void *data, struct drm_file *file_priv)
 {
@@ -1800,11 +1977,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 	struct drm_atomic_state *state;
 	struct drm_modeset_acquire_ctx ctx;
 	struct drm_plane *plane;
-	struct drm_crtc *crtc;
-	struct drm_crtc_state *crtc_state;
+	struct drm_out_fence_state *fence_state = NULL;
 	unsigned plane_mask;
 	int ret = 0;
-	unsigned int i, j;
+	unsigned int i, j, num_fences = 0;
 
 	/* disallow for drivers not supporting atomic: */
 	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -1919,20 +2095,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 		drm_mode_object_unreference(obj);
 	}
 
-	if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			struct drm_pending_vblank_event *e;
-
-			e = create_vblank_event(dev, file_priv, NULL,
-						arg->user_data);
-			if (!e) {
-				ret = -ENOMEM;
-				goto out;
-			}
-
-			crtc_state->event = e;
-		}
-	}
+	ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
+				     &num_fences);
+	if (ret)
+		goto out;
 
 	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
 		/*
@@ -1952,20 +2118,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 out:
 	drm_atomic_clean_old_fb(dev, plane_mask, ret);
 
-	if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		/*
-		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
-		 * if they weren't, this code should be called on success
-		 * for TEST_ONLY too.
-		 */
-
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			if (!crtc_state->event)
-				continue;
-
-			drm_event_cancel_free(dev, &crtc_state->event->base);
-		}
-	}
+	complete_crtc_signaling(dev, state, fence_state, num_fences, ret);
 
 	if (ret == -EDEADLK) {
 		drm_atomic_state_clear(state);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 9b9881b..e8bc1ae 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
 		drm_object_attach_property(&crtc->base, config->prop_active, 0);
 		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
+		drm_object_attach_property(&crtc->base,
+					   config->prop_out_fence_ptr, 0);
 	}
 
 	return 0;
@@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.prop_in_fence_fd = prop;
 
+	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+			"OUT_FENCE_PTR", 0, U64_MAX);
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.prop_out_fence_ptr = prop;
+
 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
 	if (!prop)
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 331bb10..c0eaec7 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
 	struct drm_crtc *ptr;
 	struct drm_crtc_state *state;
 	struct drm_crtc_commit *commit;
+	s64 __user *out_fence_ptr;
 };
 
 struct __drm_connnectors_state {
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 0870de1..44571bc 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1264,6 +1264,12 @@ struct drm_mode_config {
 	 */
 	struct drm_property *prop_in_fence_fd;
 	/**
+	 * @prop_out_fence_ptr: Sync File fd pointer representing the
+	 * outgoing fences for a CRTC. Userspace should provide a pointer to a
+	 * value of type s64, and then cast that pointer to u64.
+	 */
+	struct drm_property *prop_out_fence_ptr;
+	/**
 	 * @prop_crtc_id: Default atomic plane property to specify the
 	 * &drm_crtc.
 	 */
-- 
2.5.5

Re: [PATCH v8 3/3] drm/fence: add out-fences support

[Sean Paul]

On Fri, Nov 11, 2016 at 9:15 AM, Gustavo Padovan <gustavo@padovan.org> wrote:
> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
> Support DRM out-fences by creating a sync_file with a fence for each CRTC
> that sets the OUT_FENCE_PTR property.
>
> We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
> the sync_file fd back to userspace.
>
> The sync_file and fd are allocated/created before commit, but the
> fd_install operation only happens after we know that commit succeed.
>
> v2: Comment by Rob Clark:
>         - Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.
>
>     Comment by Daniel Vetter:
>         - Add clean up code for out_fences
>
> v3: Comments by Daniel Vetter:
>         - create DRM_MODE_ATOMIC_EVENT_MASK
>         - userspace should fill out_fences_ptr with the crtc_ids for which
>         it wants fences back.
>
> v4: Create OUT_FENCE_PTR properties and remove old approach.
>
> v5: Comments by Brian Starkey:
>         - Remove extra fence_get() in atomic_ioctl()
>         - Check ret before iterating on the crtc_state
>         - check ret before fd_install
>         - set fence_state to NULL at the beginning
>         - check fence_state->out_fence_ptr before put_user()
>         - change order of fput() and put_unused_fd() on failure
>
>      - Add access_ok() check to the out_fence_ptr received
>      - Rebase after fence -> dma_fence rename
>      - Store out_fence_ptr in the drm_atomic_state
>      - Split crtc_setup_out_fence()
>      - return -1 as out_fence with TEST_ONLY flag
>
> v6: Comments by Daniel Vetter
>         - Add prepare/unprepare_crtc_signaling()
>         - move struct drm_out_fence_state to drm_atomic.c
>         - mark get_crtc_fence() as static
>
>     Comments by Brian Starkey
>         - proper set fence_ptr fence_state array
>         - isolate fence_idx increment
>
>     - improve error handling
>
> v7: Comments by Daniel Vetter
>         - remove prefix from internal functions
>         - make out_fence_ptr an s64 pointer
>         - degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
>         - fix doc issues
>         - filter out OUT_FENCE_PTR == NULL and do not fail in this case
>         - add complete_crtc_signalling()
>         - krealloc fence_state on demand
>
>     Comment by Brian Starkey
>         - remove unused crtc_state arg from get_out_fence()
>
> v8: Comment by Brian Starkey
>         - cancel events before check for !fence_state
>         - convert a few lefovers u64 types for out_fence_ptr
>         - fix memleak by assign fence_state earlier after realloc
>         - proper accout num_fences in case of error
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

A couple of nits below, other than that, looks good to me

> ---
>  drivers/gpu/drm/drm_atomic.c | 243 +++++++++++++++++++++++++++++++++++--------
>  drivers/gpu/drm/drm_crtc.c   |   8 ++
>  include/drm/drm_atomic.h     |   1 +
>  include/drm/drm_crtc.h       |   6 ++
>  4 files changed, 213 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 8e26ad1..34cdc6e 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
>  }
>  EXPORT_SYMBOL(drm_atomic_get_crtc_state);
>
> +static void set_out_fence_for_crtc(struct drm_atomic_state *state,
> +                                  struct drm_crtc *crtc, s64 __user *fence_ptr)
> +{
> +       state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
> +}
> +
> +static s64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
> +                                          struct drm_crtc *crtc)
> +{
> +       s64 __user *fence_ptr;
> +
> +       fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
> +       state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
> +
> +       return fence_ptr;
> +}
> +
>  /**
>   * drm_atomic_set_mode_for_crtc - set mode for CRTC
>   * @state: the CRTC whose incoming state to update
> @@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
>                                         &replaced);
>                 state->color_mgmt_changed |= replaced;
>                 return ret;
> +       } else if (property == config->prop_out_fence_ptr) {
> +               s64 __user *fence_ptr = u64_to_user_ptr(val);
> +
> +               if (!fence_ptr)
> +                       return 0;
> +
> +               if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
> +                       return -EFAULT;
> +
> +               set_out_fence_for_crtc(state->state, crtc, fence_ptr);
>         } else if (crtc->funcs->atomic_set_property)
>                 return crtc->funcs->atomic_set_property(crtc, state, property, val);
>         else
> @@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
>                 *val = (state->ctm) ? state->ctm->base.id : 0;
>         else if (property == config->gamma_lut_property)
>                 *val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
> +       else if (property == config->prop_out_fence_ptr)
> +               *val = 0;
>         else if (crtc->funcs->atomic_get_property)
>                 return crtc->funcs->atomic_get_property(crtc, state, property, val);
>         else
> @@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
>   */
>
>  static struct drm_pending_vblank_event *create_vblank_event(
> -               struct drm_device *dev, struct drm_file *file_priv,
> -               struct dma_fence *fence, uint64_t user_data)
> +               struct drm_device *dev, uint64_t user_data)
>  {
>         struct drm_pending_vblank_event *e = NULL;
> -       int ret;
>
>         e = kzalloc(sizeof *e, GFP_KERNEL);
>         if (!e)
> @@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
>         e->event.base.length = sizeof(e->event);
>         e->event.user_data = user_data;
>
> -       if (file_priv) {
> -               ret = drm_event_reserve_init(dev, file_priv, &e->base,
> -                                            &e->event.base);
> -               if (ret) {
> -                       kfree(e);
> -                       return NULL;
> -               }
> -       }
> -
> -       e->base.fence = fence;
> -
>         return e;
>  }
>
> @@ -1788,6 +1804,167 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL(drm_atomic_clean_old_fb);
>
> +static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
> +{
> +       struct dma_fence *fence;
> +
> +       fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> +       if (!fence)
> +               return NULL;
> +
> +       dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
> +                      crtc->fence_context, ++crtc->fence_seqno);
> +
> +       return fence;
> +}
> +
> +struct drm_out_fence_state {
> +       s64 __user *out_fence_ptr;
> +       struct sync_file *sync_file;
> +       int fd;
> +};
> +
> +static int setup_out_fence(struct drm_out_fence_state *fence_state,
> +                          struct dma_fence *fence)
> +{
> +       fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
> +       if (fence_state->fd < 0)
> +               return fence_state->fd;
> +
> +       if (put_user(fence_state->fd, fence_state->out_fence_ptr))
> +               return -EFAULT;
> +
> +       fence_state->sync_file = sync_file_create(fence);
> +       if(!fence_state->sync_file)
> +               return -ENOMEM;
> +
> +       return 0;
> +}
> +
> +static int prepare_crtc_signaling(struct drm_device *dev,
> +                                 struct drm_atomic_state *state,
> +                                 struct drm_mode_atomic *arg,
> +                                 struct drm_file *file_priv,
> +                                 struct drm_out_fence_state **fence_state,
> +                                 unsigned int *num_fences)
> +{
> +       struct drm_crtc *crtc;
> +       struct drm_crtc_state *crtc_state;
> +       int i, ret;
> +
> +       for_each_crtc_in_state(state, crtc, crtc_state, i) {
> +               u64 __user *fence_ptr;
> +
> +               fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
> +
> +               if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) {
> +                       if (put_user(-1, fence_ptr))
> +                               return -EFAULT;
> +
> +                       continue;
> +               }
> +
> +               if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {

pedantic suggestion: If you did the inverse, you could just continue
and save yourself some indentation (and instantiate e once). ie:

if (!(arg->flags & DRM_MODE_PAGE_FLIP_EVENT) && !fence_ptr)
        continue;

...


> +                       struct drm_pending_vblank_event *e;
> +
> +                       e = create_vblank_event(dev, arg->user_data);
> +                       if (!e)
> +                               return -ENOMEM;
> +
> +                       crtc_state->event = e;
> +               }
> +
> +               if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
> +                       struct drm_pending_vblank_event *e = crtc_state->event;
> +
> +                       if (!file_priv)
> +                               continue;
> +
> +                       ret = drm_event_reserve_init(dev, file_priv, &e->base,
> +                                                    &e->event.base);
> +                       if (ret) {
> +                               kfree(e);
> +                               crtc_state->event = NULL;
> +                               return ret;
> +                       }
> +               }
> +
> +               if (fence_ptr) {
> +                       struct dma_fence *fence;
> +                       struct drm_out_fence_state *f;
> +
> +                       f = krealloc(*fence_state, sizeof(**fence_state) *
> +                                    (*num_fences + 1), GFP_KERNEL);
> +                       if (!f)
> +                               return -ENOMEM;
> +
> +                       f[*num_fences].out_fence_ptr = fence_ptr;
> +                       *fence_state = f;
> +
> +                       fence = get_crtc_fence(crtc);
> +                       if (!fence) {
> +                               (*num_fences)++;
> +                               return -ENOMEM;
> +                       }
> +
> +                       ret = setup_out_fence(&f[(*num_fences)++], fence);
> +                       if (ret) {
> +                               dma_fence_put(fence);
> +                               return ret;
> +                       }
> +
> +                       crtc_state->event->base.fence = fence;
> +
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static void complete_crtc_signaling(struct drm_device *dev,
> +                                    struct drm_atomic_state *state,
> +                                    struct drm_out_fence_state *fence_state,
> +                                    unsigned int num_fences, int ret)
> +{
> +       struct drm_crtc *crtc;
> +       struct drm_crtc_state *crtc_state;
> +       int i;
> +
> +       if (!ret) {

I don't think there's any reason to smash the fd install and clean-up
into one function. I think splitting into 2 functions and calling the
right one from atomic_ioctl would be better.

> +               for (i = 0; i < num_fences; i++)
> +                       fd_install(fence_state[i].fd,
> +                                  fence_state[i].sync_file->file);
> +               return;
> +       }
> +
> +       for_each_crtc_in_state(state, crtc, crtc_state, i) {
> +               /*
> +                * TEST_ONLY and PAGE_FLIP_EVENT are mutually
> +                * exclusive, if they weren't, this code should be
> +                * called on success for TEST_ONLY too.
> +                */
> +               if (crtc_state->event)
> +                       drm_event_cancel_free(dev, &crtc_state->event->base);
> +       }
> +
> +       if (!fence_state)
> +               return;
> +
> +       for (i = 0; i < num_fences; i++) {
> +               if (fence_state[i].sync_file)
> +                       fput(fence_state[i].sync_file->file);
> +               if (fence_state[i].fd >= 0)
> +                       put_unused_fd(fence_state[i].fd);
> +
> +               /* If this fails log error to the user */
> +               if (fence_state[i].out_fence_ptr &&
> +                   put_user(-1, fence_state[i].out_fence_ptr))
> +                       DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
> +       }
> +
> +       kfree(fence_state);
> +}
> +
>  int drm_mode_atomic_ioctl(struct drm_device *dev,
>                           void *data, struct drm_file *file_priv)
>  {
> @@ -1800,11 +1977,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
>         struct drm_atomic_state *state;
>         struct drm_modeset_acquire_ctx ctx;
>         struct drm_plane *plane;
> -       struct drm_crtc *crtc;
> -       struct drm_crtc_state *crtc_state;
> +       struct drm_out_fence_state *fence_state = NULL;
>         unsigned plane_mask;
>         int ret = 0;
> -       unsigned int i, j;
> +       unsigned int i, j, num_fences = 0;
>
>         /* disallow for drivers not supporting atomic: */
>         if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
> @@ -1919,20 +2095,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
>                 drm_mode_object_unreference(obj);
>         }
>
> -       if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
> -               for_each_crtc_in_state(state, crtc, crtc_state, i) {
> -                       struct drm_pending_vblank_event *e;
> -
> -                       e = create_vblank_event(dev, file_priv, NULL,
> -                                               arg->user_data);
> -                       if (!e) {
> -                               ret = -ENOMEM;
> -                               goto out;
> -                       }
> -
> -                       crtc_state->event = e;
> -               }
> -       }
> +       ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
> +                                    &num_fences);
> +       if (ret)
> +               goto out;
>
>         if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
>                 /*
> @@ -1952,20 +2118,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
>  out:
>         drm_atomic_clean_old_fb(dev, plane_mask, ret);
>
> -       if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
> -               /*
> -                * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
> -                * if they weren't, this code should be called on success
> -                * for TEST_ONLY too.
> -                */
> -
> -               for_each_crtc_in_state(state, crtc, crtc_state, i) {
> -                       if (!crtc_state->event)
> -                               continue;
> -
> -                       drm_event_cancel_free(dev, &crtc_state->event->base);
> -               }
> -       }
> +       complete_crtc_signaling(dev, state, fence_state, num_fences, ret);
>
>         if (ret == -EDEADLK) {
>                 drm_atomic_state_clear(state);
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 9b9881b..e8bc1ae 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
>         if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
>                 drm_object_attach_property(&crtc->base, config->prop_active, 0);
>                 drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
> +               drm_object_attach_property(&crtc->base,
> +                                          config->prop_out_fence_ptr, 0);
>         }
>
>         return 0;
> @@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>                 return -ENOMEM;
>         dev->mode_config.prop_in_fence_fd = prop;
>
> +       prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
> +                       "OUT_FENCE_PTR", 0, U64_MAX);
> +       if (!prop)
> +               return -ENOMEM;
> +       dev->mode_config.prop_out_fence_ptr = prop;
> +
>         prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
>                         "CRTC_ID", DRM_MODE_OBJECT_CRTC);
>         if (!prop)
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index 331bb10..c0eaec7 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -144,6 +144,7 @@ struct __drm_crtcs_state {
>         struct drm_crtc *ptr;
>         struct drm_crtc_state *state;
>         struct drm_crtc_commit *commit;
> +       s64 __user *out_fence_ptr;
>  };
>
>  struct __drm_connnectors_state {
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 0870de1..44571bc 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1264,6 +1264,12 @@ struct drm_mode_config {
>          */
>         struct drm_property *prop_in_fence_fd;
>         /**
> +        * @prop_out_fence_ptr: Sync File fd pointer representing the
> +        * outgoing fences for a CRTC. Userspace should provide a pointer to a
> +        * value of type s64, and then cast that pointer to u64.
> +        */
> +       struct drm_property *prop_out_fence_ptr;
> +       /**
>          * @prop_crtc_id: Default atomic plane property to specify the
>          * &drm_crtc.
>          */
> --
> 2.5.5
>

Re: [PATCH v8 3/3] drm/fence: add out-fences support

[Daniel Vetter]

On Fri, Nov 11, 2016 at 11:48:09AM -0500, Sean Paul wrote:
> On Fri, Nov 11, 2016 at 9:15 AM, Gustavo Padovan <gustavo@padovan.org> wrote:
> > +static void complete_crtc_signaling(struct drm_device *dev,
> > +                                    struct drm_atomic_state *state,
> > +                                    struct drm_out_fence_state *fence_state,
> > +                                    unsigned int num_fences, int ret)
> > +{
> > +       struct drm_crtc *crtc;
> > +       struct drm_crtc_state *crtc_state;
> > +       int i;
> > +
> > +       if (!ret) {
> 
> I don't think there's any reason to smash the fd install and clean-up
> into one function. I think splitting into 2 functions and calling the
> right one from atomic_ioctl would be better.

Hm, I suggested this because the control flow in one of Gustavo's earlier
patches look really funny. I guess it could be split up again, but with
both callers in the current position. tbh I don't care whether it's this
or that, both are clear improvement over the older version.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v8 3/3] drm/fence: add out-fences support

[Sean Paul]

On Fri, Nov 11, 2016 at 12:11 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Nov 11, 2016 at 11:48:09AM -0500, Sean Paul wrote:
>> On Fri, Nov 11, 2016 at 9:15 AM, Gustavo Padovan <gustavo@padovan.org> wrote:
>> > +static void complete_crtc_signaling(struct drm_device *dev,
>> > +                                    struct drm_atomic_state *state,
>> > +                                    struct drm_out_fence_state *fence_state,
>> > +                                    unsigned int num_fences, int ret)
>> > +{
>> > +       struct drm_crtc *crtc;
>> > +       struct drm_crtc_state *crtc_state;
>> > +       int i;
>> > +
>> > +       if (!ret) {
>>
>> I don't think there's any reason to smash the fd install and clean-up
>> into one function. I think splitting into 2 functions and calling the
>> right one from atomic_ioctl would be better.
>
> Hm, I suggested this because the control flow in one of Gustavo's earlier
> patches look really funny. I guess it could be split up again, but with
> both callers in the current position. tbh I don't care whether it's this
> or that, both are clear improvement over the older version.

I really don't have a strong opinion either. Perhaps meet in the
middle and pass bool install_fds instead of ret (since that's kind of
an anti-pattern)?

Sean


> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

Re: [PATCH v8 3/3] drm/fence: add out-fences support

[Brian Starkey]

Spotted one more thing on a cleanup path...

On Fri, Nov 11, 2016 at 11:15:59PM +0900, Gustavo Padovan wrote:
>From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
>Support DRM out-fences by creating a sync_file with a fence for each CRTC
>that sets the OUT_FENCE_PTR property.
>
>We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
>the sync_file fd back to userspace.
>
>The sync_file and fd are allocated/created before commit, but the
>fd_install operation only happens after we know that commit succeed.
>
>v2: Comment by Rob Clark:
>	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.
>
>    Comment by Daniel Vetter:
>	- Add clean up code for out_fences
>
>v3: Comments by Daniel Vetter:
>	- create DRM_MODE_ATOMIC_EVENT_MASK
>	- userspace should fill out_fences_ptr with the crtc_ids for which
>	it wants fences back.
>
>v4: Create OUT_FENCE_PTR properties and remove old approach.
>
>v5: Comments by Brian Starkey:
>	- Remove extra fence_get() in atomic_ioctl()
>	- Check ret before iterating on the crtc_state
>	- check ret before fd_install
>	- set fence_state to NULL at the beginning
>	- check fence_state->out_fence_ptr before put_user()
>	- change order of fput() and put_unused_fd() on failure
>
>     - Add access_ok() check to the out_fence_ptr received
>     - Rebase after fence -> dma_fence rename
>     - Store out_fence_ptr in the drm_atomic_state
>     - Split crtc_setup_out_fence()
>     - return -1 as out_fence with TEST_ONLY flag
>
>v6: Comments by Daniel Vetter
>	- Add prepare/unprepare_crtc_signaling()
>	- move struct drm_out_fence_state to drm_atomic.c
>	- mark get_crtc_fence() as static
>
>    Comments by Brian Starkey
>	- proper set fence_ptr fence_state array
>	- isolate fence_idx increment
>
>    - improve error handling
>
>v7: Comments by Daniel Vetter
>	- remove prefix from internal functions
>	- make out_fence_ptr an s64 pointer
>	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
>	- fix doc issues
>	- filter out OUT_FENCE_PTR == NULL and do not fail in this case
>	- add complete_crtc_signalling()
>	- krealloc fence_state on demand
>
>    Comment by Brian Starkey
>	- remove unused crtc_state arg from get_out_fence()
>
>v8: Comment by Brian Starkey
>	- cancel events before check for !fence_state
>	- convert a few lefovers u64 types for out_fence_ptr
>	- fix memleak by assign fence_state earlier after realloc
>	- proper accout num_fences in case of error
>
>Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>---
> drivers/gpu/drm/drm_atomic.c | 243 +++++++++++++++++++++++++++++++++++--------
> drivers/gpu/drm/drm_crtc.c   |   8 ++
> include/drm/drm_atomic.h     |   1 +
> include/drm/drm_crtc.h       |   6 ++
> 4 files changed, 213 insertions(+), 45 deletions(-)
>
>diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>index 8e26ad1..34cdc6e 100644
>--- a/drivers/gpu/drm/drm_atomic.c
>+++ b/drivers/gpu/drm/drm_atomic.c
>@@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
> }
> EXPORT_SYMBOL(drm_atomic_get_crtc_state);
>
>+static void set_out_fence_for_crtc(struct drm_atomic_state *state,
>+				   struct drm_crtc *crtc, s64 __user *fence_ptr)
>+{
>+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
>+}
>+
>+static s64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
>+					   struct drm_crtc *crtc)
>+{
>+	s64 __user *fence_ptr;
>+
>+	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
>+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
>+
>+	return fence_ptr;
>+}
>+
> /**
>  * drm_atomic_set_mode_for_crtc - set mode for CRTC
>  * @state: the CRTC whose incoming state to update
>@@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
> 					&replaced);
> 		state->color_mgmt_changed |= replaced;
> 		return ret;
>+	} else if (property == config->prop_out_fence_ptr) {
>+		s64 __user *fence_ptr = u64_to_user_ptr(val);
>+
>+		if (!fence_ptr)
>+			return 0;
>+
>+		if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
>+			return -EFAULT;
>+
>+		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
> 	} else if (crtc->funcs->atomic_set_property)
> 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
> 	else
>@@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
> 		*val = (state->ctm) ? state->ctm->base.id : 0;
> 	else if (property == config->gamma_lut_property)
> 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
>+	else if (property == config->prop_out_fence_ptr)
>+		*val = 0;
> 	else if (crtc->funcs->atomic_get_property)
> 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
> 	else
>@@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
>  */
>
> static struct drm_pending_vblank_event *create_vblank_event(
>-		struct drm_device *dev, struct drm_file *file_priv,
>-		struct dma_fence *fence, uint64_t user_data)
>+		struct drm_device *dev, uint64_t user_data)
> {
> 	struct drm_pending_vblank_event *e = NULL;
>-	int ret;
>
> 	e = kzalloc(sizeof *e, GFP_KERNEL);
> 	if (!e)
>@@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
> 	e->event.base.length = sizeof(e->event);
> 	e->event.user_data = user_data;
>
>-	if (file_priv) {
>-		ret = drm_event_reserve_init(dev, file_priv, &e->base,
>-					     &e->event.base);
>-		if (ret) {
>-			kfree(e);
>-			return NULL;
>-		}
>-	}
>-
>-	e->base.fence = fence;
>-
> 	return e;
> }
>
>@@ -1788,6 +1804,167 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
> }
> EXPORT_SYMBOL(drm_atomic_clean_old_fb);
>
>+static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
>+{
>+	struct dma_fence *fence;
>+
>+	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>+	if (!fence)
>+		return NULL;
>+
>+	dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
>+		       crtc->fence_context, ++crtc->fence_seqno);
>+
>+	return fence;
>+}
>+
>+struct drm_out_fence_state {
>+	s64 __user *out_fence_ptr;
>+	struct sync_file *sync_file;
>+	int fd;
>+};
>+
>+static int setup_out_fence(struct drm_out_fence_state *fence_state,
>+			   struct dma_fence *fence)
>+{
>+	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
>+	if (fence_state->fd < 0)
>+		return fence_state->fd;
>+
>+	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
>+		return -EFAULT;
>+
>+	fence_state->sync_file = sync_file_create(fence);
>+	if(!fence_state->sync_file)
>+		return -ENOMEM;
>+
>+	return 0;
>+}
>+
>+static int prepare_crtc_signaling(struct drm_device *dev,
>+				  struct drm_atomic_state *state,
>+				  struct drm_mode_atomic *arg,
>+				  struct drm_file *file_priv,
>+				  struct drm_out_fence_state **fence_state,
>+				  unsigned int *num_fences)
>+{
>+	struct drm_crtc *crtc;
>+	struct drm_crtc_state *crtc_state;
>+	int i, ret;
>+
>+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
>+		u64 __user *fence_ptr;
>+
>+		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
>+
>+		if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) {
>+			if (put_user(-1, fence_ptr))
>+				return -EFAULT;
>+
>+			continue;
>+		}
>+
>+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
>+			struct drm_pending_vblank_event *e;
>+
>+			e = create_vblank_event(dev, arg->user_data);
>+			if (!e)
>+				return -ENOMEM;
>+
>+			crtc_state->event = e;
>+		}
>+
>+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
>+			struct drm_pending_vblank_event *e = crtc_state->event;
>+
>+			if (!file_priv)
>+				continue;
>+
>+			ret = drm_event_reserve_init(dev, file_priv, &e->base,
>+						     &e->event.base);
>+			if (ret) {
>+				kfree(e);
>+				crtc_state->event = NULL;
>+				return ret;
>+			}
>+		}
>+
>+		if (fence_ptr) {
>+			struct dma_fence *fence;
>+			struct drm_out_fence_state *f;
>+
>+			f = krealloc(*fence_state, sizeof(**fence_state) *
>+				     (*num_fences + 1), GFP_KERNEL);
>+			if (!f)
>+				return -ENOMEM;

We have to make sure the new bit of fence_state is zeroed, otherwise
failing after the (*num_fences)++ could lead to fput/put_unused_fd on
random numbers.

-Brian

>+
>+			f[*num_fences].out_fence_ptr = fence_ptr;
>+			*fence_state = f;
>+
>+			fence = get_crtc_fence(crtc);
>+			if (!fence) {
>+				(*num_fences)++;
>+				return -ENOMEM;
>+			}
>+
>+			ret = setup_out_fence(&f[(*num_fences)++], fence);
>+			if (ret) {
>+				dma_fence_put(fence);
>+				return ret;
>+			}
>+
>+			crtc_state->event->base.fence = fence;
>+
>+		}
>+	}
>+
>+	return 0;
>+}
>+
>+static void complete_crtc_signaling(struct drm_device *dev,
>+				     struct drm_atomic_state *state,
>+				     struct drm_out_fence_state *fence_state,
>+				     unsigned int num_fences, int ret)
>+{
>+	struct drm_crtc *crtc;
>+	struct drm_crtc_state *crtc_state;
>+	int i;
>+
>+	if (!ret) {
>+		for (i = 0; i < num_fences; i++)
>+			fd_install(fence_state[i].fd,
>+				   fence_state[i].sync_file->file);
>+		return;
>+	}
>+
>+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
>+		/*
>+		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
>+		 * exclusive, if they weren't, this code should be
>+		 * called on success for TEST_ONLY too.
>+		 */
>+		if (crtc_state->event)
>+			drm_event_cancel_free(dev, &crtc_state->event->base);
>+	}
>+
>+	if (!fence_state)
>+		return;
>+
>+	for (i = 0; i < num_fences; i++) {
>+		if (fence_state[i].sync_file)
>+			fput(fence_state[i].sync_file->file);
>+		if (fence_state[i].fd >= 0)
>+			put_unused_fd(fence_state[i].fd);
>+
>+		/* If this fails log error to the user */
>+		if (fence_state[i].out_fence_ptr &&
>+		    put_user(-1, fence_state[i].out_fence_ptr))
>+			DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
>+	}
>+
>+	kfree(fence_state);
>+}
>+
> int drm_mode_atomic_ioctl(struct drm_device *dev,
> 			  void *data, struct drm_file *file_priv)
> {
>@@ -1800,11 +1977,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> 	struct drm_atomic_state *state;
> 	struct drm_modeset_acquire_ctx ctx;
> 	struct drm_plane *plane;
>-	struct drm_crtc *crtc;
>-	struct drm_crtc_state *crtc_state;
>+	struct drm_out_fence_state *fence_state = NULL;
> 	unsigned plane_mask;
> 	int ret = 0;
>-	unsigned int i, j;
>+	unsigned int i, j, num_fences = 0;
>
> 	/* disallow for drivers not supporting atomic: */
> 	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
>@@ -1919,20 +2095,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> 		drm_mode_object_unreference(obj);
> 	}
>
>-	if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
>-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
>-			struct drm_pending_vblank_event *e;
>-
>-			e = create_vblank_event(dev, file_priv, NULL,
>-						arg->user_data);
>-			if (!e) {
>-				ret = -ENOMEM;
>-				goto out;
>-			}
>-
>-			crtc_state->event = e;
>-		}
>-	}
>+	ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
>+				     &num_fences);
>+	if (ret)
>+		goto out;
>
> 	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
> 		/*
>@@ -1952,20 +2118,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> out:
> 	drm_atomic_clean_old_fb(dev, plane_mask, ret);
>
>-	if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
>-		/*
>-		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
>-		 * if they weren't, this code should be called on success
>-		 * for TEST_ONLY too.
>-		 */
>-
>-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
>-			if (!crtc_state->event)
>-				continue;
>-
>-			drm_event_cancel_free(dev, &crtc_state->event->base);
>-		}
>-	}
>+	complete_crtc_signaling(dev, state, fence_state, num_fences, ret);
>
> 	if (ret == -EDEADLK) {
> 		drm_atomic_state_clear(state);
>diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>index 9b9881b..e8bc1ae 100644
>--- a/drivers/gpu/drm/drm_crtc.c
>+++ b/drivers/gpu/drm/drm_crtc.c
>@@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
> 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
> 		drm_object_attach_property(&crtc->base, config->prop_active, 0);
> 		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
>+		drm_object_attach_property(&crtc->base,
>+					   config->prop_out_fence_ptr, 0);
> 	}
>
> 	return 0;
>@@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> 		return -ENOMEM;
> 	dev->mode_config.prop_in_fence_fd = prop;
>
>+	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
>+			"OUT_FENCE_PTR", 0, U64_MAX);
>+	if (!prop)
>+		return -ENOMEM;
>+	dev->mode_config.prop_out_fence_ptr = prop;
>+
> 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
> 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
> 	if (!prop)
>diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
>index 331bb10..c0eaec7 100644
>--- a/include/drm/drm_atomic.h
>+++ b/include/drm/drm_atomic.h
>@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
> 	struct drm_crtc *ptr;
> 	struct drm_crtc_state *state;
> 	struct drm_crtc_commit *commit;
>+	s64 __user *out_fence_ptr;
> };
>
> struct __drm_connnectors_state {
>diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>index 0870de1..44571bc 100644
>--- a/include/drm/drm_crtc.h
>+++ b/include/drm/drm_crtc.h
>@@ -1264,6 +1264,12 @@ struct drm_mode_config {
> 	 */
> 	struct drm_property *prop_in_fence_fd;
> 	/**
>+	 * @prop_out_fence_ptr: Sync File fd pointer representing the
>+	 * outgoing fences for a CRTC. Userspace should provide a pointer to a
>+	 * value of type s64, and then cast that pointer to u64.
>+	 */
>+	struct drm_property *prop_out_fence_ptr;
>+	/**
> 	 * @prop_crtc_id: Default atomic plane property to specify the
> 	 * &drm_crtc.
> 	 */
>-- 
>2.5.5
>

Re: [PATCH v8 0/3] drm: add explict fencing

[Gustavo Padovan]

Subject was supposed to be v9! sorry about that.

2016-11-11 Gustavo Padovan <gustavo@padovan.org>:

> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> 
> Hi,
> 
> Another iteration after Brian comments. Please refer to the cover letter[1] in
> a previous version to check for more details.
> 
> The changes since the last version can be seen in commit message on each patch.
> 
> Robert Foss managed to port Android's drm_hwcomposer to the new HWC2 API and
> added support to fences. Current patches can be seen here:
> 
> https://git.collabora.com/cgit/user/robertfoss/drm_hwcomposer.git/log/?h=hwc2_fence_v1
> 
> He ran AOSP on top of padovan/fences kernel branch with full fence support on
> qemu/virgl and msm db410c. That means we already have a working open source
> userspace using the explicit fencing implementation.
> 
> Also i-g-t testing are available with all tests suggested in v7 included:
> 
> https://git.collabora.com/cgit/user/padovan/intel-gpu-tools.git/log/
> 
> Please review!
> 
> Gustavo
> 
> [1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1253822.html
> 
> ---
> Gustavo Padovan (3):
>   drm/fence: add in-fences support
>   drm/fence: add fence timeline to drm_crtc
>   drm/fence: add out-fences support
> 
>  drivers/gpu/drm/Kconfig             |   1 +
>  drivers/gpu/drm/drm_atomic.c        | 257 +++++++++++++++++++++++++++++-------
>  drivers/gpu/drm/drm_atomic_helper.c |   5 +
>  drivers/gpu/drm/drm_crtc.c          |  45 +++++++
>  drivers/gpu/drm/drm_plane.c         |   1 +
>  include/drm/drm_atomic.h            |   1 +
>  include/drm/drm_crtc.h              |  56 ++++++++
>  7 files changed, 321 insertions(+), 45 deletions(-)
> 
> -- 
> 2.5.5
> 

Re: [PATCH v8 0/3] drm: add explict fencing

[Robert Foss]

I tested this series on the db410c platform and I've seen no
regressions from previous versions of this series.

Tested-by: Robert Foss <robert.foss@collabora.com>

[PATCH v8 0/3] drm: add explict fencing

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Hi,

New version of the DRM fences patches with all comments on v7 adressed. Please
refer to the cover letter[1] in a previous version to check for more details.

The changes since the last version can be seen in commit message on each patch.

Robert Foss managed to port Android's drm_hwcomposer to the new HWC2 API and
added support to fences. Current patches can be seen here:

https://git.collabora.com/cgit/user/robertfoss/drm_hwcomposer.git/log/?h=hwc2_fence_v1

He ran AOSP on top of padovan/fences kernel branch with full fence support on
qemu/virgl and msm db410c. That means we already have a working open source
userspace using the explicit fencing implementation.

Also i-g-t testing are available with all tests suggested in v7 included:

https://git.collabora.com/cgit/user/padovan/intel-gpu-tools.git/log/

Please review!

Gustavo

[1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1253822.html

---
Gustavo Padovan (3):
  drm/fence: add in-fences support
  drm/fence: add fence timeline to drm_crtc
  drm/fence: add out-fences support

 drivers/gpu/drm/Kconfig             |   1 +
 drivers/gpu/drm/drm_atomic.c        | 256 +++++++++++++++++++++++++++++-------
 drivers/gpu/drm/drm_atomic_helper.c |   5 +
 drivers/gpu/drm/drm_crtc.c          |  45 +++++++
 drivers/gpu/drm/drm_plane.c         |   1 +
 include/drm/drm_atomic.h            |   1 +
 include/drm/drm_crtc.h              |  56 ++++++++
 7 files changed, 320 insertions(+), 45 deletions(-)

-- 
2.5.5

[PATCH v8 3/3] drm/fence: add out-fences support

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Support DRM out-fences by creating a sync_file with a fence for each CRTC
that sets the OUT_FENCE_PTR property.

We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
the sync_file fd back to userspace.

The sync_file and fd are allocated/created before commit, but the
fd_install operation only happens after we know that commit succeed.

v2: Comment by Rob Clark:
	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.

    Comment by Daniel Vetter:
	- Add clean up code for out_fences

v3: Comments by Daniel Vetter:
	- create DRM_MODE_ATOMIC_EVENT_MASK
	- userspace should fill out_fences_ptr with the crtc_ids for which
	it wants fences back.

v4: Create OUT_FENCE_PTR properties and remove old approach.

v5: Comments by Brian Starkey:
	- Remove extra fence_get() in atomic_ioctl()
	- Check ret before iterating on the crtc_state
	- check ret before fd_install
	- set fence_state to NULL at the beginning
	- check fence_state->out_fence_ptr before put_user()
	- change order of fput() and put_unused_fd() on failure

     - Add access_ok() check to the out_fence_ptr received
     - Rebase after fence -> dma_fence rename
     - Store out_fence_ptr in the drm_atomic_state
     - Split crtc_setup_out_fence()
     - return -1 as out_fence with TEST_ONLY flag

v6: Comments by Daniel Vetter
	- Add prepare/unprepare_crtc_signaling()
	- move struct drm_out_fence_state to drm_atomic.c
	- mark get_crtc_fence() as static

    Comments by Brian Starkey
	- proper set fence_ptr fence_state array
	- isolate fence_idx increment

    - improve error handling

v7: Comments by Daniel Vetter
	- remove prefix from internal functions
	- make out_fence_ptr an s64 pointer
	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
	- fix doc issues
	- filter out OUT_FENCE_PTR == NULL and do fail in this case
	- add complete_crtc_signalling()
	- krealloc fence_state on demand

    Comment by Brian Starkey
	- remove unused crtc_state arg from get_out_fence()

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
 drivers/gpu/drm/drm_atomic.c | 242 +++++++++++++++++++++++++++++++++++--------
 drivers/gpu/drm/drm_crtc.c   |   8 ++
 include/drm/drm_atomic.h     |   1 +
 include/drm/drm_crtc.h       |   6 ++
 4 files changed, 212 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 8e26ad1..cd39f13 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_atomic_get_crtc_state);
 
+static void set_out_fence_for_crtc(struct drm_atomic_state *state,
+				   struct drm_crtc *crtc, u64 __user *fence_ptr)
+{
+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
+}
+
+static u64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
+					   struct drm_crtc *crtc)
+{
+	u64 __user *fence_ptr;
+
+	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
+
+	return fence_ptr;
+}
+
 /**
  * drm_atomic_set_mode_for_crtc - set mode for CRTC
  * @state: the CRTC whose incoming state to update
@@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					&replaced);
 		state->color_mgmt_changed |= replaced;
 		return ret;
+	} else if (property == config->prop_out_fence_ptr) {
+		s64 __user *fence_ptr = u64_to_user_ptr(val);
+
+		if (!fence_ptr)
+			return 0;
+
+		if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
+			return -EFAULT;
+
+		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
 	} else if (crtc->funcs->atomic_set_property)
 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
 	else
@@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
 		*val = (state->ctm) ? state->ctm->base.id : 0;
 	else if (property == config->gamma_lut_property)
 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
+	else if (property == config->prop_out_fence_ptr)
+		*val = 0;
 	else if (crtc->funcs->atomic_get_property)
 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
 	else
@@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
  */
 
 static struct drm_pending_vblank_event *create_vblank_event(
-		struct drm_device *dev, struct drm_file *file_priv,
-		struct dma_fence *fence, uint64_t user_data)
+		struct drm_device *dev, uint64_t user_data)
 {
 	struct drm_pending_vblank_event *e = NULL;
-	int ret;
 
 	e = kzalloc(sizeof *e, GFP_KERNEL);
 	if (!e)
@@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
 	e->event.base.length = sizeof(e->event);
 	e->event.user_data = user_data;
 
-	if (file_priv) {
-		ret = drm_event_reserve_init(dev, file_priv, &e->base,
-					     &e->event.base);
-		if (ret) {
-			kfree(e);
-			return NULL;
-		}
-	}
-
-	e->base.fence = fence;
-
 	return e;
 }
 
@@ -1788,6 +1804,166 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_clean_old_fb);
 
+static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
+{
+	struct dma_fence *fence;
+
+	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+	if (!fence)
+		return NULL;
+
+	dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
+		       crtc->fence_context, ++crtc->fence_seqno);
+
+	return fence;
+}
+
+struct drm_out_fence_state {
+	s64 __user *out_fence_ptr;
+	struct sync_file *sync_file;
+	int fd;
+};
+
+static int setup_out_fence(struct drm_out_fence_state *fence_state,
+			   struct dma_fence *fence)
+{
+	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fence_state->fd < 0)
+		return fence_state->fd;
+
+	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
+		return -EFAULT;
+
+	fence_state->sync_file = sync_file_create(fence);
+	if(!fence_state->sync_file)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int prepare_crtc_signaling(struct drm_device *dev,
+				  struct drm_atomic_state *state,
+				  struct drm_mode_atomic *arg,
+				  struct drm_file *file_priv,
+				  struct drm_out_fence_state **fence_state,
+				  unsigned int *num_fences)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i, ret;
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		u64 __user *fence_ptr;
+
+		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
+
+		if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) {
+			if (put_user(-1, fence_ptr))
+				return -EFAULT;
+
+			continue;
+		}
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
+			struct drm_pending_vblank_event *e;
+
+			e = create_vblank_event(dev, arg->user_data);
+			if (!e)
+				return -ENOMEM;
+
+			crtc_state->event = e;
+		}
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
+			struct drm_pending_vblank_event *e = crtc_state->event;
+
+			if (!file_priv)
+				continue;
+
+			ret = drm_event_reserve_init(dev, file_priv, &e->base,
+						     &e->event.base);
+			if (ret) {
+				kfree(e);
+				crtc_state->event = NULL;
+				return ret;
+			}
+		}
+
+		if (fence_ptr) {
+			struct dma_fence *fence;
+			struct drm_out_fence_state *f;
+
+			f = krealloc(*fence_state, sizeof(**fence_state) *
+				     (*num_fences + 1), GFP_KERNEL);
+			if (!f)
+				return -ENOMEM;
+
+			f[*num_fences].out_fence_ptr = fence_ptr;
+
+			fence = get_crtc_fence(crtc);
+			if (!fence)
+				return -ENOMEM;
+
+			ret = setup_out_fence(&f[*num_fences], fence);
+			if (ret) {
+				dma_fence_put(fence);
+				return ret;
+			}
+
+			(*num_fences)++;
+
+			*fence_state = f;
+			crtc_state->event->base.fence = fence;
+		}
+	}
+
+	return 0;
+}
+
+static void complete_crtc_signaling(struct drm_device *dev,
+				     struct drm_atomic_state *state,
+				     struct drm_out_fence_state *fence_state,
+				     unsigned int num_fences, int ret)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i;
+
+	if (!ret) {
+		for (i = 0; i < num_fences; i++)
+			fd_install(fence_state[i].fd,
+				   fence_state[i].sync_file->file);
+		return;
+	}
+
+	if (!fence_state)
+		return;
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		/*
+		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
+		 * exclusive, if they weren't, this code should be
+		 * called on success for TEST_ONLY too.
+		 */
+		if (crtc_state->event)
+			drm_event_cancel_free(dev, &crtc_state->event->base);
+	}
+
+	for (i = 0; i < num_fences; i++) {
+		if (fence_state[i].sync_file)
+			fput(fence_state[i].sync_file->file);
+		if (fence_state[i].fd >= 0)
+			put_unused_fd(fence_state[i].fd);
+
+		/* If this fails log error to the user */
+		if (fence_state[i].out_fence_ptr &&
+		    put_user(-1, fence_state[i].out_fence_ptr))
+			DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
+	}
+
+	kfree(fence_state);
+}
+
 int drm_mode_atomic_ioctl(struct drm_device *dev,
 			  void *data, struct drm_file *file_priv)
 {
@@ -1800,11 +1976,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 	struct drm_atomic_state *state;
 	struct drm_modeset_acquire_ctx ctx;
 	struct drm_plane *plane;
-	struct drm_crtc *crtc;
-	struct drm_crtc_state *crtc_state;
+	struct drm_out_fence_state *fence_state = NULL;
 	unsigned plane_mask;
 	int ret = 0;
-	unsigned int i, j;
+	unsigned int i, j, num_fences = 0;
 
 	/* disallow for drivers not supporting atomic: */
 	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -1919,20 +2094,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 		drm_mode_object_unreference(obj);
 	}
 
-	if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			struct drm_pending_vblank_event *e;
-
-			e = create_vblank_event(dev, file_priv, NULL,
-						arg->user_data);
-			if (!e) {
-				ret = -ENOMEM;
-				goto out;
-			}
-
-			crtc_state->event = e;
-		}
-	}
+	ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
+				     &num_fences);
+	if (ret)
+		goto out;
 
 	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
 		/*
@@ -1952,20 +2117,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 out:
 	drm_atomic_clean_old_fb(dev, plane_mask, ret);
 
-	if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		/*
-		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
-		 * if they weren't, this code should be called on success
-		 * for TEST_ONLY too.
-		 */
-
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			if (!crtc_state->event)
-				continue;
-
-			drm_event_cancel_free(dev, &crtc_state->event->base);
-		}
-	}
+	complete_crtc_signaling(dev, state, fence_state, num_fences, ret);
 
 	if (ret == -EDEADLK) {
 		drm_atomic_state_clear(state);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 9b9881b..e8bc1ae 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
 		drm_object_attach_property(&crtc->base, config->prop_active, 0);
 		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
+		drm_object_attach_property(&crtc->base,
+					   config->prop_out_fence_ptr, 0);
 	}
 
 	return 0;
@@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.prop_in_fence_fd = prop;
 
+	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+			"OUT_FENCE_PTR", 0, U64_MAX);
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.prop_out_fence_ptr = prop;
+
 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
 	if (!prop)
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 331bb10..c0eaec7 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
 	struct drm_crtc *ptr;
 	struct drm_crtc_state *state;
 	struct drm_crtc_commit *commit;
+	s64 __user *out_fence_ptr;
 };
 
 struct __drm_connnectors_state {
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 0870de1..44571bc 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1264,6 +1264,12 @@ struct drm_mode_config {
 	 */
 	struct drm_property *prop_in_fence_fd;
 	/**
+	 * @prop_out_fence_ptr: Sync File fd pointer representing the
+	 * outgoing fences for a CRTC. Userspace should provide a pointer to a
+	 * value of type s64, and then cast that pointer to u64.
+	 */
+	struct drm_property *prop_out_fence_ptr;
+	/**
 	 * @prop_crtc_id: Default atomic plane property to specify the
 	 * &drm_crtc.
 	 */
-- 
2.5.5

Re: [PATCH v8 3/3] drm/fence: add out-fences support

[Brian Starkey]

Hi Gustavo,

On Fri, Nov 11, 2016 at 02:16:09PM +0900, Gustavo Padovan wrote:
>From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
>Support DRM out-fences by creating a sync_file with a fence for each CRTC
>that sets the OUT_FENCE_PTR property.
>
>We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
>the sync_file fd back to userspace.
>
>The sync_file and fd are allocated/created before commit, but the
>fd_install operation only happens after we know that commit succeed.
>
>v2: Comment by Rob Clark:
>	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.
>
>    Comment by Daniel Vetter:
>	- Add clean up code for out_fences
>
>v3: Comments by Daniel Vetter:
>	- create DRM_MODE_ATOMIC_EVENT_MASK
>	- userspace should fill out_fences_ptr with the crtc_ids for which
>	it wants fences back.
>
>v4: Create OUT_FENCE_PTR properties and remove old approach.
>
>v5: Comments by Brian Starkey:
>	- Remove extra fence_get() in atomic_ioctl()
>	- Check ret before iterating on the crtc_state
>	- check ret before fd_install
>	- set fence_state to NULL at the beginning
>	- check fence_state->out_fence_ptr before put_user()
>	- change order of fput() and put_unused_fd() on failure
>
>     - Add access_ok() check to the out_fence_ptr received
>     - Rebase after fence -> dma_fence rename
>     - Store out_fence_ptr in the drm_atomic_state
>     - Split crtc_setup_out_fence()
>     - return -1 as out_fence with TEST_ONLY flag
>
>v6: Comments by Daniel Vetter
>	- Add prepare/unprepare_crtc_signaling()
>	- move struct drm_out_fence_state to drm_atomic.c
>	- mark get_crtc_fence() as static
>
>    Comments by Brian Starkey
>	- proper set fence_ptr fence_state array
>	- isolate fence_idx increment
>
>    - improve error handling
>
>v7: Comments by Daniel Vetter
>	- remove prefix from internal functions
>	- make out_fence_ptr an s64 pointer
>	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
>	- fix doc issues
>	- filter out OUT_FENCE_PTR == NULL and do fail in this case

Do *not* fail in this case?

>	- add complete_crtc_signalling()
>	- krealloc fence_state on demand
>
>    Comment by Brian Starkey
>	- remove unused crtc_state arg from get_out_fence()
>
>Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

 From an integration with writeback point of view, this looks fine to
me - I can add writeback to this easily.

A few comments below though:

>---
> drivers/gpu/drm/drm_atomic.c | 242 +++++++++++++++++++++++++++++++++++--------
> drivers/gpu/drm/drm_crtc.c   |   8 ++
> include/drm/drm_atomic.h     |   1 +
> include/drm/drm_crtc.h       |   6 ++
> 4 files changed, 212 insertions(+), 45 deletions(-)
>
>diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>index 8e26ad1..cd39f13 100644
>--- a/drivers/gpu/drm/drm_atomic.c
>+++ b/drivers/gpu/drm/drm_atomic.c
>@@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
> }
> EXPORT_SYMBOL(drm_atomic_get_crtc_state);
>
>+static void set_out_fence_for_crtc(struct drm_atomic_state *state,
>+				   struct drm_crtc *crtc, u64 __user *fence_ptr)
>+{
>+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
>+}
>+
>+static u64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
>+					   struct drm_crtc *crtc)
>+{
>+	u64 __user *fence_ptr;
>+
>+	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
>+	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
>+
>+	return fence_ptr;
>+}
>+

You missed a couple of s/u64/s64/ in the two functions above.

> /**
>  * drm_atomic_set_mode_for_crtc - set mode for CRTC
>  * @state: the CRTC whose incoming state to update
>@@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
> 					&replaced);
> 		state->color_mgmt_changed |= replaced;
> 		return ret;
>+	} else if (property == config->prop_out_fence_ptr) {
>+		s64 __user *fence_ptr = u64_to_user_ptr(val);
>+
>+		if (!fence_ptr)
>+			return 0;
>+
>+		if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
>+			return -EFAULT;
>+
>+		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
> 	} else if (crtc->funcs->atomic_set_property)
> 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
> 	else
>@@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
> 		*val = (state->ctm) ? state->ctm->base.id : 0;
> 	else if (property == config->gamma_lut_property)
> 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
>+	else if (property == config->prop_out_fence_ptr)
>+		*val = 0;
> 	else if (crtc->funcs->atomic_get_property)
> 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
> 	else
>@@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
>  */
>
> static struct drm_pending_vblank_event *create_vblank_event(
>-		struct drm_device *dev, struct drm_file *file_priv,
>-		struct dma_fence *fence, uint64_t user_data)
>+		struct drm_device *dev, uint64_t user_data)
> {
> 	struct drm_pending_vblank_event *e = NULL;
>-	int ret;
>
> 	e = kzalloc(sizeof *e, GFP_KERNEL);
> 	if (!e)
>@@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
> 	e->event.base.length = sizeof(e->event);
> 	e->event.user_data = user_data;
>
>-	if (file_priv) {
>-		ret = drm_event_reserve_init(dev, file_priv, &e->base,
>-					     &e->event.base);
>-		if (ret) {
>-			kfree(e);
>-			return NULL;
>-		}
>-	}
>-
>-	e->base.fence = fence;
>-
> 	return e;
> }
>
>@@ -1788,6 +1804,166 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
> }
> EXPORT_SYMBOL(drm_atomic_clean_old_fb);
>
>+static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
>+{
>+	struct dma_fence *fence;
>+
>+	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>+	if (!fence)
>+		return NULL;
>+
>+	dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
>+		       crtc->fence_context, ++crtc->fence_seqno);
>+
>+	return fence;
>+}
>+
>+struct drm_out_fence_state {
>+	s64 __user *out_fence_ptr;
>+	struct sync_file *sync_file;
>+	int fd;
>+};
>+
>+static int setup_out_fence(struct drm_out_fence_state *fence_state,
>+			   struct dma_fence *fence)
>+{
>+	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
>+	if (fence_state->fd < 0)
>+		return fence_state->fd;
>+
>+	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
>+		return -EFAULT;
>+
>+	fence_state->sync_file = sync_file_create(fence);
>+	if(!fence_state->sync_file)
>+		return -ENOMEM;
>+
>+	return 0;
>+}
>+
>+static int prepare_crtc_signaling(struct drm_device *dev,
>+				  struct drm_atomic_state *state,
>+				  struct drm_mode_atomic *arg,
>+				  struct drm_file *file_priv,
>+				  struct drm_out_fence_state **fence_state,
>+				  unsigned int *num_fences)
>+{
>+	struct drm_crtc *crtc;
>+	struct drm_crtc_state *crtc_state;
>+	int i, ret;
>+
>+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
>+		u64 __user *fence_ptr;
>+
>+		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
>+
>+		if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) {
>+			if (put_user(-1, fence_ptr))
>+				return -EFAULT;
>+
>+			continue;
>+		}
>+
>+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
>+			struct drm_pending_vblank_event *e;
>+
>+			e = create_vblank_event(dev, arg->user_data);
>+			if (!e)
>+				return -ENOMEM;
>+
>+			crtc_state->event = e;
>+		}
>+
>+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
>+			struct drm_pending_vblank_event *e = crtc_state->event;
>+
>+			if (!file_priv)
>+				continue;
>+
>+			ret = drm_event_reserve_init(dev, file_priv, &e->base,
>+						     &e->event.base);
>+			if (ret) {
>+				kfree(e);
>+				crtc_state->event = NULL;
>+				return ret;
>+			}
>+		}
>+
>+		if (fence_ptr) {
>+			struct dma_fence *fence;
>+			struct drm_out_fence_state *f;
>+
>+			f = krealloc(*fence_state, sizeof(**fence_state) *
>+				     (*num_fences + 1), GFP_KERNEL);
>+			if (!f)
>+				return -ENOMEM;
>+
>+			f[*num_fences].out_fence_ptr = fence_ptr;
>+
>+			fence = get_crtc_fence(crtc);
>+			if (!fence)
>+				return -ENOMEM;
>+
>+			ret = setup_out_fence(&f[*num_fences], fence);
>+			if (ret) {
>+				dma_fence_put(fence);
>+				return ret;
>+			}

Looks to me that the cleanup path doesn't work here. If
setup_out_fence fails, you bail out before incrementing num_fences,
and so the cleanup loop will be an iteration short.

>+
>+			(*num_fences)++;
>+
>+			*fence_state = f;

I think this is problematic too. If I understand krealloc right, when
you bail out before here and f != *fence_state, then the old
*fence_state will have been already freed, and f is going to leak.

>+			crtc_state->event->base.fence = fence;
>+		}
>+	}
>+
>+	return 0;
>+}
>+
>+static void complete_crtc_signaling(struct drm_device *dev,
>+				     struct drm_atomic_state *state,
>+				     struct drm_out_fence_state *fence_state,
>+				     unsigned int num_fences, int ret)
>+{
>+	struct drm_crtc *crtc;
>+	struct drm_crtc_state *crtc_state;
>+	int i;
>+
>+	if (!ret) {
>+		for (i = 0; i < num_fences; i++)
>+			fd_install(fence_state[i].fd,
>+				   fence_state[i].sync_file->file);
>+		return;
>+	}
>+
>+	if (!fence_state)
>+		return;
>+
>+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
>+		/*
>+		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
>+		 * exclusive, if they weren't, this code should be
>+		 * called on success for TEST_ONLY too.
>+		 */
>+		if (crtc_state->event)
>+			drm_event_cancel_free(dev, &crtc_state->event->base);
>+	}

I think this event cleanup needs to be before the !fence_state check;
userspace can ask for events but no fences, and if that fails then the
events need to be freed.

Cheers,
-Brian

>+
>+	for (i = 0; i < num_fences; i++) {
>+		if (fence_state[i].sync_file)
>+			fput(fence_state[i].sync_file->file);
>+		if (fence_state[i].fd >= 0)
>+			put_unused_fd(fence_state[i].fd);
>+
>+		/* If this fails log error to the user */
>+		if (fence_state[i].out_fence_ptr &&
>+		    put_user(-1, fence_state[i].out_fence_ptr))
>+			DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
>+	}
>+
>+	kfree(fence_state);
>+}
>+
> int drm_mode_atomic_ioctl(struct drm_device *dev,
> 			  void *data, struct drm_file *file_priv)
> {
>@@ -1800,11 +1976,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> 	struct drm_atomic_state *state;
> 	struct drm_modeset_acquire_ctx ctx;
> 	struct drm_plane *plane;
>-	struct drm_crtc *crtc;
>-	struct drm_crtc_state *crtc_state;
>+	struct drm_out_fence_state *fence_state = NULL;
> 	unsigned plane_mask;
> 	int ret = 0;
>-	unsigned int i, j;
>+	unsigned int i, j, num_fences = 0;
>
> 	/* disallow for drivers not supporting atomic: */
> 	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
>@@ -1919,20 +2094,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> 		drm_mode_object_unreference(obj);
> 	}
>
>-	if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
>-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
>-			struct drm_pending_vblank_event *e;
>-
>-			e = create_vblank_event(dev, file_priv, NULL,
>-						arg->user_data);
>-			if (!e) {
>-				ret = -ENOMEM;
>-				goto out;
>-			}
>-
>-			crtc_state->event = e;
>-		}
>-	}
>+	ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
>+				     &num_fences);
>+	if (ret)
>+		goto out;
>
> 	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
> 		/*
>@@ -1952,20 +2117,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> out:
> 	drm_atomic_clean_old_fb(dev, plane_mask, ret);
>
>-	if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
>-		/*
>-		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
>-		 * if they weren't, this code should be called on success
>-		 * for TEST_ONLY too.
>-		 */
>-
>-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
>-			if (!crtc_state->event)
>-				continue;
>-
>-			drm_event_cancel_free(dev, &crtc_state->event->base);
>-		}
>-	}
>+	complete_crtc_signaling(dev, state, fence_state, num_fences, ret);
>
> 	if (ret == -EDEADLK) {
> 		drm_atomic_state_clear(state);
>diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>index 9b9881b..e8bc1ae 100644
>--- a/drivers/gpu/drm/drm_crtc.c
>+++ b/drivers/gpu/drm/drm_crtc.c
>@@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
> 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
> 		drm_object_attach_property(&crtc->base, config->prop_active, 0);
> 		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
>+		drm_object_attach_property(&crtc->base,
>+					   config->prop_out_fence_ptr, 0);
> 	}
>
> 	return 0;
>@@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> 		return -ENOMEM;
> 	dev->mode_config.prop_in_fence_fd = prop;
>
>+	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
>+			"OUT_FENCE_PTR", 0, U64_MAX);
>+	if (!prop)
>+		return -ENOMEM;
>+	dev->mode_config.prop_out_fence_ptr = prop;
>+
> 	prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
> 			"CRTC_ID", DRM_MODE_OBJECT_CRTC);
> 	if (!prop)
>diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
>index 331bb10..c0eaec7 100644
>--- a/include/drm/drm_atomic.h
>+++ b/include/drm/drm_atomic.h
>@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
> 	struct drm_crtc *ptr;
> 	struct drm_crtc_state *state;
> 	struct drm_crtc_commit *commit;
>+	s64 __user *out_fence_ptr;
> };
>
> struct __drm_connnectors_state {
>diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>index 0870de1..44571bc 100644
>--- a/include/drm/drm_crtc.h
>+++ b/include/drm/drm_crtc.h
>@@ -1264,6 +1264,12 @@ struct drm_mode_config {
> 	 */
> 	struct drm_property *prop_in_fence_fd;
> 	/**
>+	 * @prop_out_fence_ptr: Sync File fd pointer representing the
>+	 * outgoing fences for a CRTC. Userspace should provide a pointer to a
>+	 * value of type s64, and then cast that pointer to u64.
>+	 */
>+	struct drm_property *prop_out_fence_ptr;
>+	/**
> 	 * @prop_crtc_id: Default atomic plane property to specify the
> 	 * &drm_crtc.
> 	 */
>-- 
>2.5.5
>

Re: [PATCH v8 3/3] drm/fence: add out-fences support

[Gustavo Padovan]

Hi Brian,

2016-11-11 Brian Starkey <brian.starkey@arm.com>:

> Hi Gustavo,
> 
> On Fri, Nov 11, 2016 at 02:16:09PM +0900, Gustavo Padovan wrote:
> > From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> > 
> > Support DRM out-fences by creating a sync_file with a fence for each CRTC
> > that sets the OUT_FENCE_PTR property.
> > 
> > We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
> > the sync_file fd back to userspace.
> > 
> > The sync_file and fd are allocated/created before commit, but the
> > fd_install operation only happens after we know that commit succeed.
> > 
> > v2: Comment by Rob Clark:
> > 	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.
> > 
> >    Comment by Daniel Vetter:
> > 	- Add clean up code for out_fences
> > 
> > v3: Comments by Daniel Vetter:
> > 	- create DRM_MODE_ATOMIC_EVENT_MASK
> > 	- userspace should fill out_fences_ptr with the crtc_ids for which
> > 	it wants fences back.
> > 
> > v4: Create OUT_FENCE_PTR properties and remove old approach.
> > 
> > v5: Comments by Brian Starkey:
> > 	- Remove extra fence_get() in atomic_ioctl()
> > 	- Check ret before iterating on the crtc_state
> > 	- check ret before fd_install
> > 	- set fence_state to NULL at the beginning
> > 	- check fence_state->out_fence_ptr before put_user()
> > 	- change order of fput() and put_unused_fd() on failure
> > 
> >     - Add access_ok() check to the out_fence_ptr received
> >     - Rebase after fence -> dma_fence rename
> >     - Store out_fence_ptr in the drm_atomic_state
> >     - Split crtc_setup_out_fence()
> >     - return -1 as out_fence with TEST_ONLY flag
> > 
> > v6: Comments by Daniel Vetter
> > 	- Add prepare/unprepare_crtc_signaling()
> > 	- move struct drm_out_fence_state to drm_atomic.c
> > 	- mark get_crtc_fence() as static
> > 
> >    Comments by Brian Starkey
> > 	- proper set fence_ptr fence_state array
> > 	- isolate fence_idx increment
> > 
> >    - improve error handling
> > 
> > v7: Comments by Daniel Vetter
> > 	- remove prefix from internal functions
> > 	- make out_fence_ptr an s64 pointer
> > 	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
> > 	- fix doc issues
> > 	- filter out OUT_FENCE_PTR == NULL and do fail in this case
> 
> Do *not* fail in this case?
> 
> > 	- add complete_crtc_signalling()
> > 	- krealloc fence_state on demand
> > 
> >    Comment by Brian Starkey
> > 	- remove unused crtc_state arg from get_out_fence()
> > 
> > Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> 
> From an integration with writeback point of view, this looks fine to
> me - I can add writeback to this easily.
> 
> A few comments below though:
> 
> > ---
> > drivers/gpu/drm/drm_atomic.c | 242 +++++++++++++++++++++++++++++++++++--------
> > drivers/gpu/drm/drm_crtc.c   |   8 ++
> > include/drm/drm_atomic.h     |   1 +
> > include/drm/drm_crtc.h       |   6 ++
> > 4 files changed, 212 insertions(+), 45 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> > index 8e26ad1..cd39f13 100644
> > --- a/drivers/gpu/drm/drm_atomic.c
> > +++ b/drivers/gpu/drm/drm_atomic.c
> > @@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
> > }
> > EXPORT_SYMBOL(drm_atomic_get_crtc_state);
> > 
> > +static void set_out_fence_for_crtc(struct drm_atomic_state *state,
> > +				   struct drm_crtc *crtc, u64 __user *fence_ptr)
> > +{
> > +	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
> > +}
> > +
> > +static u64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state,
> > +					   struct drm_crtc *crtc)
> > +{
> > +	u64 __user *fence_ptr;
> > +
> > +	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
> > +	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
> > +
> > +	return fence_ptr;
> > +}
> > +
> 
> You missed a couple of s/u64/s64/ in the two functions above.
> 
> > /**
> >  * drm_atomic_set_mode_for_crtc - set mode for CRTC
> >  * @state: the CRTC whose incoming state to update
> > @@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
> > 					&replaced);
> > 		state->color_mgmt_changed |= replaced;
> > 		return ret;
> > +	} else if (property == config->prop_out_fence_ptr) {
> > +		s64 __user *fence_ptr = u64_to_user_ptr(val);
> > +
> > +		if (!fence_ptr)
> > +			return 0;
> > +
> > +		if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
> > +			return -EFAULT;
> > +
> > +		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
> > 	} else if (crtc->funcs->atomic_set_property)
> > 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
> > 	else
> > @@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
> > 		*val = (state->ctm) ? state->ctm->base.id : 0;
> > 	else if (property == config->gamma_lut_property)
> > 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
> > +	else if (property == config->prop_out_fence_ptr)
> > +		*val = 0;
> > 	else if (crtc->funcs->atomic_get_property)
> > 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
> > 	else
> > @@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
> >  */
> > 
> > static struct drm_pending_vblank_event *create_vblank_event(
> > -		struct drm_device *dev, struct drm_file *file_priv,
> > -		struct dma_fence *fence, uint64_t user_data)
> > +		struct drm_device *dev, uint64_t user_data)
> > {
> > 	struct drm_pending_vblank_event *e = NULL;
> > -	int ret;
> > 
> > 	e = kzalloc(sizeof *e, GFP_KERNEL);
> > 	if (!e)
> > @@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
> > 	e->event.base.length = sizeof(e->event);
> > 	e->event.user_data = user_data;
> > 
> > -	if (file_priv) {
> > -		ret = drm_event_reserve_init(dev, file_priv, &e->base,
> > -					     &e->event.base);
> > -		if (ret) {
> > -			kfree(e);
> > -			return NULL;
> > -		}
> > -	}
> > -
> > -	e->base.fence = fence;
> > -
> > 	return e;
> > }
> > 
> > @@ -1788,6 +1804,166 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
> > }
> > EXPORT_SYMBOL(drm_atomic_clean_old_fb);
> > 
> > +static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
> > +{
> > +	struct dma_fence *fence;
> > +
> > +	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> > +	if (!fence)
> > +		return NULL;
> > +
> > +	dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
> > +		       crtc->fence_context, ++crtc->fence_seqno);
> > +
> > +	return fence;
> > +}
> > +
> > +struct drm_out_fence_state {
> > +	s64 __user *out_fence_ptr;
> > +	struct sync_file *sync_file;
> > +	int fd;
> > +};
> > +
> > +static int setup_out_fence(struct drm_out_fence_state *fence_state,
> > +			   struct dma_fence *fence)
> > +{
> > +	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
> > +	if (fence_state->fd < 0)
> > +		return fence_state->fd;
> > +
> > +	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
> > +		return -EFAULT;
> > +
> > +	fence_state->sync_file = sync_file_create(fence);
> > +	if(!fence_state->sync_file)
> > +		return -ENOMEM;
> > +
> > +	return 0;
> > +}
> > +
> > +static int prepare_crtc_signaling(struct drm_device *dev,
> > +				  struct drm_atomic_state *state,
> > +				  struct drm_mode_atomic *arg,
> > +				  struct drm_file *file_priv,
> > +				  struct drm_out_fence_state **fence_state,
> > +				  unsigned int *num_fences)
> > +{
> > +	struct drm_crtc *crtc;
> > +	struct drm_crtc_state *crtc_state;
> > +	int i, ret;
> > +
> > +	for_each_crtc_in_state(state, crtc, crtc_state, i) {
> > +		u64 __user *fence_ptr;
> > +
> > +		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
> > +
> > +		if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) {
> > +			if (put_user(-1, fence_ptr))
> > +				return -EFAULT;
> > +
> > +			continue;
> > +		}
> > +
> > +		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
> > +			struct drm_pending_vblank_event *e;
> > +
> > +			e = create_vblank_event(dev, arg->user_data);
> > +			if (!e)
> > +				return -ENOMEM;
> > +
> > +			crtc_state->event = e;
> > +		}
> > +
> > +		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
> > +			struct drm_pending_vblank_event *e = crtc_state->event;
> > +
> > +			if (!file_priv)
> > +				continue;
> > +
> > +			ret = drm_event_reserve_init(dev, file_priv, &e->base,
> > +						     &e->event.base);
> > +			if (ret) {
> > +				kfree(e);
> > +				crtc_state->event = NULL;
> > +				return ret;
> > +			}
> > +		}
> > +
> > +		if (fence_ptr) {
> > +			struct dma_fence *fence;
> > +			struct drm_out_fence_state *f;
> > +
> > +			f = krealloc(*fence_state, sizeof(**fence_state) *
> > +				     (*num_fences + 1), GFP_KERNEL);
> > +			if (!f)
> > +				return -ENOMEM;
> > +
> > +			f[*num_fences].out_fence_ptr = fence_ptr;
> > +
> > +			fence = get_crtc_fence(crtc);
> > +			if (!fence)
> > +				return -ENOMEM;
> > +
> > +			ret = setup_out_fence(&f[*num_fences], fence);
> > +			if (ret) {
> > +				dma_fence_put(fence);
> > +				return ret;
> > +			}
> 
> Looks to me that the cleanup path doesn't work here. If
> setup_out_fence fails, you bail out before incrementing num_fences,
> and so the cleanup loop will be an iteration short.
> 
> > +
> > +			(*num_fences)++;
> > +
> > +			*fence_state = f;
> 
> I think this is problematic too. If I understand krealloc right, when
> you bail out before here and f != *fence_state, then the old
> *fence_state will have been already freed, and f is going to leak.

Yes, it is broken, I missed that. I think for fence_state I can just
move the assignment a few lines above and for num_fences one way is to
increment it before returning on error.

> 
> > +			crtc_state->event->base.fence = fence;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void complete_crtc_signaling(struct drm_device *dev,
> > +				     struct drm_atomic_state *state,
> > +				     struct drm_out_fence_state *fence_state,
> > +				     unsigned int num_fences, int ret)
> > +{
> > +	struct drm_crtc *crtc;
> > +	struct drm_crtc_state *crtc_state;
> > +	int i;
> > +
> > +	if (!ret) {
> > +		for (i = 0; i < num_fences; i++)
> > +			fd_install(fence_state[i].fd,
> > +				   fence_state[i].sync_file->file);
> > +		return;
> > +	}
> > +
> > +	if (!fence_state)
> > +		return;
> > +
> > +	for_each_crtc_in_state(state, crtc, crtc_state, i) {
> > +		/*
> > +		 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
> > +		 * exclusive, if they weren't, this code should be
> > +		 * called on success for TEST_ONLY too.
> > +		 */
> > +		if (crtc_state->event)
> > +			drm_event_cancel_free(dev, &crtc_state->event->base);
> > +	}
> 
> I think this event cleanup needs to be before the !fence_state check;
> userspace can ask for events but no fences, and if that fails then the
> events need to be freed.

Yes. In the previous version this was the correct flow, but with v8 the
clean up actually needs to happen before.

Gustavo