From fd921693fe989afe82600d97b37f54c942a6db6c Mon Sep 17 00:00:00 2001 From: David Stevens Date: Thu, 8 Apr 2021 18:54:28 +0900 Subject: [PATCH] drm/syncobj: use newly allocated stub fences MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens Link: https://patchwork.freedesktop.org/patch/msgid/20210408095428.3983055-1-stevensd@google.com Reviewed-by: Christian König Signed-off-by: Christian König --- drivers/dma-buf/dma-fence.c | 27 ++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 25 +++++++++++++++++++------ include/linux/dma-fence.h | 1 + 3 files changed, 46 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03..ce0f5ef 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -123,7 +123,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -142,6 +144,29 @@ struct dma_fence *dma_fence_get_stub(void) EXPORT_SYMBOL(dma_fence_get_stub); /** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct dma_fence *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + dma_fence_init(fence, + &dma_fence_stub_ops, + &dma_fence_stub_lock, + 0, 0); + dma_fence_signal(fence); + + return fence; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + +/** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate * diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 6231a82..fdd2ec8 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,16 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + + if (IS_ERR(fence)) + return PTR_ERR(fence); drm_syncobj_replace_fence(syncobj, fence); dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -478,6 +482,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -488,8 +493,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1334,8 +1344,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efa..6ffb4b2 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.7.4