[RFC v2 8/8] drm/fence: add out-fences support
Daniel Vetter
daniel at ffwll.ch
Tue Apr 26 14:53:05 UTC 2016
On Mon, Apr 25, 2016 at 07:33:28PM -0300, Gustavo Padovan wrote:
> From: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
>
> Support DRM out-fences creating a sync_file with a fence for each crtc
> update with the DRM_MODE_ATOMIC_OUT_FENCE flag.
>
> We then send an struct drm_out_fences array with the out-fences fds back in
> the drm_atomic_ioctl() as an out arg in the out_fences_ptr field.
>
> struct drm_out_fences {
> __u32 crtc_id;
> __u32 fd;
> };
>
> 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
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
> ---
> drivers/gpu/drm/drm_atomic.c | 163 +++++++++++++++++++++++++++++++++++++++++--
> include/drm/drm_crtc.h | 10 +++
> include/uapi/drm/drm_mode.h | 11 ++-
> 3 files changed, 179 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 5f9d434..06c6007 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -1566,6 +1566,133 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
> }
> EXPORT_SYMBOL(drm_atomic_clean_old_fb);
>
> +static struct drm_out_fence_state *get_out_fence(struct drm_device *dev,
> + struct drm_atomic_state *state,
> + uint32_t __user *out_fences_ptr,
> + uint64_t count_out_fences,
> + uint64_t user_data)
> +{
> + struct drm_crtc *crtc;
> + struct drm_crtc_state *crtc_state;
> + struct drm_out_fences *out_fences;
> + struct drm_out_fence_state *fence_state;
> + int num_fences = 0;
> + int i, ret;
> +
> + if (count_out_fences > dev->mode_config.num_crtc)
> + return ERR_PTR(-EINVAL);
> +
> + out_fences = kcalloc(count_out_fences, sizeof(*out_fences),
> + GFP_KERNEL);
> + if (!out_fences)
> + return ERR_PTR(-ENOMEM);
A bit tricky, but the above kcalloc is the only thing that catches integer
overflows in count_out_fences. Needs a comment imo since this could be a
security exploit if we accidentally screw it up.
Also needs a testcase imo.
> +
> + fence_state = kcalloc(count_out_fences, sizeof(*fence_state),
> + GFP_KERNEL);
> + if (!fence_state) {
> + kfree(out_fences);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + for (i = 0 ; i < count_out_fences ; i++)
> + fence_state[i].fd = -1;
> +
> + for_each_crtc_in_state(state, crtc, crtc_state, i) {
> + struct drm_pending_vblank_event *e;
> + struct fence *fence;
> + char name[32];
> +
> + fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> + if (!fence) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
> + crtc->fence_context, crtc->fence_seqno);
> +
> + snprintf(name, sizeof(name), "crtc-%d_%lu",
> + drm_crtc_index(crtc), crtc->fence_seqno++);
Hm ... fence_init_with_name? I'm kinda confused why we only name fences
that are exported though, and why not all of them. Debugging fence
deadlocks is real hard, so giving them all names might be a good idea.
Anyway, seems like more room for a bit more sync_file/struct fence
merging.
> +
> + fence_state[i].fd = get_unused_fd_flags(O_CLOEXEC);
> + if (fence_state[i].fd < 0) {
> + fence_put(fence);
> + ret = fence_state[i].fd;
> + goto out;
> + }
> +
> + fence_state[i].sync_file = sync_file_create(name, fence);
> + if(!fence_state[i].sync_file) {
> + fence_put(fence);
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + if (crtc_state->event) {
> + crtc_state->event->base.fence = fence;
> + } else {
This looks a bit funny - I'd change the create event logic to create an
event either if we have the either drm event or out-fence flag set.
> + e = create_vblank_event(dev, NULL, fence, user_data);
> + if (!e) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + crtc_state->event = e;
> + }
> +
> + out_fences[num_fences].crtc_id = crtc->base.id;
> + out_fences[num_fences].fd = fence_state[i].fd;
> + num_fences++;
> + }
> +
> + if (copy_to_user(out_fences_ptr, out_fences,
> + num_fences * sizeof(*out_fences))) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + kfree(out_fences);
> +
> + return fence_state;
> +
> +out:
> + for (i = 0 ; i < count_out_fences ; i++) {
> + if (fence_state[i].sync_file)
> + sync_file_put(fence_state[i].sync_file);
> + if (fence_state[i].fd >= 0)
> + put_unused_fd(fence_state[i].fd);
> + }
> +
> + kfree(fence_state);
> + kfree(out_fences);
> +
> + return ERR_PTR(ret);
> +}
> +
> +static void install_out_fence(uint64_t count_out_fences,
> + struct drm_out_fence_state *state)
> +{
> + int i;
> +
> + for (i = 0 ; i < count_out_fences ; i++) {
> + if (state[i].sync_file)
> + sync_file_install(state[i].sync_file, state[i].fd);
Is sync_file_install anything more than fd_install? Imo a wrapper for
just that function is overkill and just hides stuff. I'd nuke it (another
sync_file patch though). In dma-buf we also don't wrap it, we only have a
convenience wrapper for users who want to combine the
get_unused_flags+fd_install in one go. And maybe even that is silly.
Ok, I unlazied and it's indeed just a silly wrapper. Please nuke it.
> + }
> +}
> +
> +static void release_out_fence(uint64_t count_out_fences,
> + struct drm_out_fence_state *state)
> +{
> + int i;
> +
> + for (i = 0 ; i < count_out_fences ; i++) {
> + if (state->sync_file)
> + sync_file_put(state->sync_file);
> + if (state->fd >= 0)
> + put_unused_fd(state->fd);
> + }
> +}
> +
> int drm_mode_atomic_ioctl(struct drm_device *dev,
> void *data, struct drm_file *file_priv)
> {
> @@ -1574,12 +1701,14 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> uint32_t __user *count_props_ptr = (uint32_t __user *)(unsigned long)(arg->count_props_ptr);
> uint32_t __user *props_ptr = (uint32_t __user *)(unsigned long)(arg->props_ptr);
> uint64_t __user *prop_values_ptr = (uint64_t __user *)(unsigned long)(arg->prop_values_ptr);
> + uint32_t __user *out_fences_ptr = (uint32_t __user *)(unsigned long)(arg->out_fences_ptr);
> unsigned int copied_objs, copied_props;
> 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;
> @@ -1605,9 +1734,13 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
> !dev->mode_config.async_page_flip)
> return -EINVAL;
>
> + if ((arg->flags & DRM_MODE_ATOMIC_OUT_FENCE) && !arg->count_out_fences)
> + return -EINVAL;
We need testcases which check that arg->count_out_fences and
arg->out_fences are 0 when the OUT_FENCE flag is not set.
Definitely needs an igt testcase for this invalid input case. Ofc we also
need tests that give the kernel nonsens in count_out_fences and out_fences
with the flag set.
> +
> /* can't test and expect an event at the same time. */
> if ((arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) &&
> - (arg->flags & DRM_MODE_PAGE_FLIP_EVENT))
> + (arg->flags & (DRM_MODE_PAGE_FLIP_EVENT
> + | DRM_MODE_ATOMIC_OUT_FENCE)))
If you go with my suggestion above to create the event if either is set,
maybe a DRM_MODE_ATOMIC_EVENT_MASK with both? Would read easier.
> return -EINVAL;
>
> drm_modeset_acquire_init(&ctx, 0);
> @@ -1699,16 +1832,30 @@ retry:
> }
> }
>
> + if (arg->flags & DRM_MODE_ATOMIC_OUT_FENCE) {
> + fence_state = get_out_fence(dev, state, out_fences_ptr,
> + arg->count_out_fences,
> + arg->user_data);
> + if (IS_ERR(fence_state)) {
> + ret = PTR_ERR(fence_state);
> + goto out;
> + }
> + }
> +
> if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
> /*
> * Unlike commit, check_only does not clean up state.
> * Below we call drm_atomic_state_free for it.
> */
> ret = drm_atomic_check_only(state);
> - } else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
> - ret = drm_atomic_async_commit(state);
> } else {
> - ret = drm_atomic_commit(state);
> + if (arg->flags & DRM_MODE_ATOMIC_OUT_FENCE)
> + install_out_fence(arg->count_out_fences, fence_state);
> +
> + if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK)
> + ret = drm_atomic_async_commit(state);
> + else
> + ret = drm_atomic_commit(state);
> }
>
> out:
> @@ -1729,6 +1876,14 @@ out:
> }
> }
>
> + if ((arg->flags & DRM_MODE_ATOMIC_OUT_FENCE) &&
> + !IS_ERR_OR_NULL(fence_state)) {
> + if (ret)
> + release_out_fence(arg->count_out_fences, fence_state);
> +
> + kfree(fence_state);
> + }
> +
> if (ret == -EDEADLK) {
> drm_atomic_state_clear(state);
> drm_modeset_backoff(&ctx);
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index d8c32c8..5f7c272 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -798,6 +798,16 @@ static inline struct drm_crtc *fence_to_crtc(struct fence *fence)
> }
>
> /**
> + * struct drm_out_fence_state - store out_fence data for clean up
> + * @sync_file: sync_file related to the out_fence
> + * @fd: file descriptor to installed on the sync_file.
> + */
> +struct drm_out_fence_state {
> + struct sync_file *sync_file;
> + int fd;
> +};
> +
> +/**
> * struct drm_connector_state - mutable connector state
> * @connector: backpointer to the connector
> * @crtc: CRTC to connect connector to, NULL if disabled
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 7a7856e..4cdcd22 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -582,13 +582,20 @@ struct drm_mode_destroy_dumb {
> #define DRM_MODE_ATOMIC_TEST_ONLY 0x0100
> #define DRM_MODE_ATOMIC_NONBLOCK 0x0200
> #define DRM_MODE_ATOMIC_ALLOW_MODESET 0x0400
> +#define DRM_MODE_ATOMIC_OUT_FENCE 0x0800
>
> #define DRM_MODE_ATOMIC_FLAGS (\
> DRM_MODE_PAGE_FLIP_EVENT |\
> DRM_MODE_PAGE_FLIP_ASYNC |\
> DRM_MODE_ATOMIC_TEST_ONLY |\
> DRM_MODE_ATOMIC_NONBLOCK |\
> - DRM_MODE_ATOMIC_ALLOW_MODESET)
> + DRM_MODE_ATOMIC_ALLOW_MODESET |\
> + DRM_MODE_ATOMIC_OUT_FENCE)
> +
> +struct drm_out_fences {
> + __u32 crtc_id;
> + __u32 fd;
> +};
>
> struct drm_mode_atomic {
> __u32 flags;
> @@ -599,6 +606,8 @@ struct drm_mode_atomic {
> __u64 prop_values_ptr;
> __u64 reserved;
> __u64 user_data;
> + __u64 count_out_fences;
> + __u64 out_fences_ptr;
> };
>
> /**
> --
> 2.5.5
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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