[PATCH 3/6] drm: add support of syncobj timeline point wait v2

Zhou, David(ChunMing) David1.Zhou at amd.com
Fri Sep 21 07:15:28 UTC 2018



> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Christian K?nig
> Sent: Thursday, September 20, 2018 7:11 PM
> To: Zhou, David(ChunMing) <David1.Zhou at amd.com>; dri-
> devel at lists.freedesktop.org
> Cc: amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH 3/6] drm: add support of syncobj timeline point wait v2
> 
> Am 20.09.2018 um 13:03 schrieb Chunming Zhou:
> > points array is one-to-one match with syncobjs array.
> > v2:
> > add seperate ioctl for timeline point wait, otherwise break uapi.
> >
> > Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
> > ---
> >   drivers/gpu/drm/drm_internal.h |  2 +
> >   drivers/gpu/drm/drm_ioctl.c    |  2 +
> >   drivers/gpu/drm/drm_syncobj.c  | 99
> +++++++++++++++++++++++++++++-----
> >   include/uapi/drm/drm.h         | 14 +++++
> >   4 files changed, 103 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_internal.h
> > b/drivers/gpu/drm/drm_internal.h index 0c4eb4a9ab31..566d44e3c782
> > 100644
> > --- a/drivers/gpu/drm/drm_internal.h
> > +++ b/drivers/gpu/drm/drm_internal.h
> > @@ -183,6 +183,8 @@ int drm_syncobj_fd_to_handle_ioctl(struct
> drm_device *dev, void *data,
> >   				   struct drm_file *file_private);
> >   int drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
> >   			   struct drm_file *file_private);
> > +int drm_syncobj_timeline_wait_ioctl(struct drm_device *dev, void *data,
> > +				    struct drm_file *file_private);
> >   int drm_syncobj_reset_ioctl(struct drm_device *dev, void *data,
> >   			    struct drm_file *file_private);
> >   int drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
> > diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> > index 6b4a633b4240..c0891614f516 100644
> > --- a/drivers/gpu/drm/drm_ioctl.c
> > +++ b/drivers/gpu/drm/drm_ioctl.c
> > @@ -669,6 +669,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
> >   		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
> >   	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_WAIT,
> drm_syncobj_wait_ioctl,
> >   		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
> > +	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT,
> drm_syncobj_timeline_wait_ioctl,
> > +		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
> >   	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_RESET,
> drm_syncobj_reset_ioctl,
> >   		      DRM_UNLOCKED|DRM_RENDER_ALLOW),
> >   	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_SIGNAL,
> drm_syncobj_signal_ioctl,
> > diff --git a/drivers/gpu/drm/drm_syncobj.c
> > b/drivers/gpu/drm/drm_syncobj.c index 67472bd77c83..a43de0e4616c
> > 100644
> > --- a/drivers/gpu/drm/drm_syncobj.c
> > +++ b/drivers/gpu/drm/drm_syncobj.c
> > @@ -126,13 +126,14 @@ static void
> drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
> >   }
> >
> >   static int drm_syncobj_fence_get_or_add_callback(struct drm_syncobj
> > *syncobj,
> > +						 u64 point,
> >   						 struct dma_fence **fence,
> >   						 struct drm_syncobj_cb *cb,
> >   						 drm_syncobj_func_t func)
> >   {
> >   	int ret;
> >
> > -	ret = drm_syncobj_search_fence(syncobj, 0, 0, fence);
> > +	ret = drm_syncobj_search_fence(syncobj, point, 0, fence);
> >   	if (!ret)
> >   		return 1;
> >
> > @@ -143,7 +144,7 @@ static int
> drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj,
> >   	 */
> >   	if (!list_empty(&syncobj->signal_pt_list)) {
> >   		spin_unlock(&syncobj->lock);
> > -		drm_syncobj_search_fence(syncobj, 0, 0, fence);
> > +		drm_syncobj_search_fence(syncobj, point, 0, fence);
> >   		if (*fence)
> >   			return 1;
> >   		spin_lock(&syncobj->lock);
> > @@ -358,7 +359,9 @@ void drm_syncobj_replace_fence(struct
> drm_syncobj *syncobj,
> >   		spin_lock(&syncobj->lock);
> >   		list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node)
> {
> >   			list_del_init(&cur->node);
> > +			spin_unlock(&syncobj->lock);
> >   			cur->func(syncobj, cur);
> > +			spin_lock(&syncobj->lock);
> 
> That looks fishy to me. Why do we need to unlock 

Cb func will call _search_fence, which will need to grab the lock, otherwise deadlock.


>and who guarantees that
> tmp is still valid when we grab the lock again?

Sorry for that, quickly  fix deadlock and forget to care that when debug.
How about splice to a tmp list, and then list_for _xxx without lock?

Any other comment on patch series and libdrm patches?   That one comment increases a patch set version seems be overcommit. 

Thanks,
David Zhou

> 
> Apart from that can't see anything obvious wrong, but I certainly need to
> take a closer look.
> 
> Christian.
> 
> >   		}
> >   		spin_unlock(&syncobj->lock);
> >   	}
> > @@ -856,6 +859,7 @@ struct syncobj_wait_entry {
> >   	struct dma_fence *fence;
> >   	struct dma_fence_cb fence_cb;
> >   	struct drm_syncobj_cb syncobj_cb;
> > +	u64    point;
> >   };
> >
> >   static void syncobj_wait_fence_func(struct dma_fence *fence, @@
> > -873,12 +877,13 @@ static void syncobj_wait_syncobj_func(struct
> drm_syncobj *syncobj,
> >   	struct syncobj_wait_entry *wait =
> >   		container_of(cb, struct syncobj_wait_entry, syncobj_cb);
> >
> > -	drm_syncobj_search_fence(syncobj, 0, 0, &wait->fence);
> > +	drm_syncobj_search_fence(syncobj, wait->point, 0, &wait->fence);
> >
> >   	wake_up_process(wait->task);
> >   }
> >
> >   static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj
> > **syncobjs,
> > +						  void __user *user_points,
> >   						  uint32_t count,
> >   						  uint32_t flags,
> >   						  signed long timeout,
> > @@ -886,13 +891,27 @@ static signed long
> drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
> >   {
> >   	struct syncobj_wait_entry *entries;
> >   	struct dma_fence *fence;
> > +	uint64_t *points;
> >   	signed long ret;
> >   	uint32_t signaled_count, i;
> >
> > -	entries = kcalloc(count, sizeof(*entries), GFP_KERNEL);
> > -	if (!entries)
> > +	points = kmalloc_array(count, sizeof(*points), GFP_KERNEL);
> > +	if (points == NULL)
> >   		return -ENOMEM;
> >
> > +	if (!user_points) {
> > +		memset(points, 0, count * sizeof(uint64_t));
> > +	} else if (copy_from_user(points, user_points, sizeof(uint64_t) *
> count)) {
> > +		ret = -EFAULT;
> > +		goto err_free_points;
> > +	}
> > +
> > +
> > +	entries = kcalloc(count, sizeof(*entries), GFP_KERNEL);
> > +	if (!entries) {
> > +		ret = -ENOMEM;
> > +		goto err_free_points;
> > +	}
> >   	/* Walk the list of sync objects and initialize entries.  We do
> >   	 * this up-front so that we can properly return -EINVAL if there is
> >   	 * a syncobj with a missing fence and then never have the chance of
> > @@ -901,7 +920,8 @@ static signed long
> drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
> >   	signaled_count = 0;
> >   	for (i = 0; i < count; ++i) {
> >   		entries[i].task = current;
> > -		ret = drm_syncobj_search_fence(syncobjs[i], 0, 0,
> > +		entries[i].point = points[i];
> > +		ret = drm_syncobj_search_fence(syncobjs[i], points[i], 0,
> >   					       &entries[i].fence);
> >   		if (!entries[i].fence) {
> >   			if (flags &
> DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) { @@ -940,6
> > +960,7 @@ static signed long drm_syncobj_array_wait_timeout(struct
> drm_syncobj **syncobjs,
> >   	if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
> >   		for (i = 0; i < count; ++i) {
> >
> 	drm_syncobj_fence_get_or_add_callback(syncobjs[i],
> > +							      entries[i].point,
> >   							      &entries[i].fence,
> >
> &entries[i].syncobj_cb,
> >
> syncobj_wait_syncobj_func); @@ -1003,6 +1024,9 @@
> > static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj
> **syncobjs,
> >   	}
> >   	kfree(entries);
> >
> > +err_free_points:
> > +	kfree(points);
> > +
> >   	return ret;
> >   }
> >
> > @@ -1041,20 +1065,33 @@ static signed long
> drm_timeout_abs_to_jiffies(int64_t timeout_nsec)
> >   static int drm_syncobj_array_wait(struct drm_device *dev,
> >   				  struct drm_file *file_private,
> >   				  struct drm_syncobj_wait *wait,
> > -				  struct drm_syncobj **syncobjs)
> > +				  struct drm_syncobj_timeline_wait
> *timeline_wait,
> > +				  struct drm_syncobj **syncobjs, bool
> timeline)
> >   {
> > -	signed long timeout = drm_timeout_abs_to_jiffies(wait-
> >timeout_nsec);
> > +	signed long timeout = 0;
> >   	signed long ret = 0;
> >   	uint32_t first = ~0;
> >
> > -	ret = drm_syncobj_array_wait_timeout(syncobjs,
> > -					     wait->count_handles,
> > -					     wait->flags,
> > -					     timeout, &first);
> > +	if (!timeline) {
> > +		timeout = drm_timeout_abs_to_jiffies(wait->timeout_nsec);
> > +		ret = drm_syncobj_array_wait_timeout(syncobjs,
> > +						     NULL,
> > +						     wait->count_handles,
> > +						     wait->flags,
> > +						     timeout, &first);
> > +		wait->first_signaled = first;
> > +	} else {
> > +		timeout = drm_timeout_abs_to_jiffies(timeline_wait-
> >timeout_nsec);
> > +		ret = drm_syncobj_array_wait_timeout(syncobjs,
> > +
> u64_to_user_ptr(timeline_wait->points),
> > +						     timeline_wait-
> >count_handles,
> > +						     timeline_wait->flags,
> > +						     timeout, &first);
> > +		timeline_wait->first_signaled = first;
> > +	}
> >   	if (ret < 0)
> >   		return ret;
> >
> > -	wait->first_signaled = first;
> >   	if (ret == 0)
> >   		return -ETIME;
> >   	return 0;
> > @@ -1142,13 +1179,47 @@ drm_syncobj_wait_ioctl(struct drm_device
> *dev, void *data,
> >   		return ret;
> >
> >   	ret = drm_syncobj_array_wait(dev, file_private,
> > -				     args, syncobjs);
> > +				     args, NULL, syncobjs, false);
> >
> >   	drm_syncobj_array_free(syncobjs, args->count_handles);
> >
> >   	return ret;
> >   }
> >
> > +int
> > +drm_syncobj_timeline_wait_ioctl(struct drm_device *dev, void *data,
> > +				struct drm_file *file_private)
> > +{
> > +	struct drm_syncobj_timeline_wait *args = data;
> > +	struct drm_syncobj **syncobjs;
> > +	int ret = 0;
> > +
> > +	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
> > +		return -ENODEV;
> > +
> > +	if (args->flags & ~(DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL |
> > +
> DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT))
> > +		return -EINVAL;
> > +
> > +	if (args->count_handles == 0)
> > +		return -EINVAL;
> > +
> > +	ret = drm_syncobj_array_find(file_private,
> > +				     u64_to_user_ptr(args->handles),
> > +				     args->count_handles,
> > +				     &syncobjs);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = drm_syncobj_array_wait(dev, file_private,
> > +				     NULL, args, syncobjs, true);
> > +
> > +	drm_syncobj_array_free(syncobjs, args->count_handles);
> > +
> > +	return ret;
> > +}
> > +
> > +
> >   int
> >   drm_syncobj_reset_ioctl(struct drm_device *dev, void *data,
> >   			struct drm_file *file_private)
> > diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index
> > cebdb2541eb7..501e86d81f47 100644
> > --- a/include/uapi/drm/drm.h
> > +++ b/include/uapi/drm/drm.h
> > @@ -748,6 +748,19 @@ struct drm_syncobj_wait {
> >   	__u32 pad;
> >   };
> >
> > +struct drm_syncobj_timeline_wait {
> > +	__u64 handles;
> > +	/* wait on specific timeline point for every handles*/
> > +	__u64 points;
> > +	/* absolute timeout */
> > +	__s64 timeout_nsec;
> > +	__u32 count_handles;
> > +	__u32 flags;
> > +	__u32 first_signaled; /* only valid when not waiting all */
> > +	__u32 pad;
> > +};
> > +
> > +
> >   struct drm_syncobj_array {
> >   	__u64 handles;
> >   	__u32 count_handles;
> > @@ -910,6 +923,7 @@ extern "C" {
> >   #define DRM_IOCTL_MODE_GET_LEASE	DRM_IOWR(0xC8, struct
> drm_mode_get_lease)
> >   #define DRM_IOCTL_MODE_REVOKE_LEASE	DRM_IOWR(0xC9,
> struct drm_mode_revoke_lease)
> >
> > +#define DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT	DRM_IOWR(0xCA,
> struct drm_syncobj_timeline_wait)
> >   /**
> >    * Device specific ioctls should only be in their respective headers
> >    * The device specific ioctl range is from 0x40 to 0x9f.
> 
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