Re: [PATCH v8 3/3] drm/fence: add out-fences support
From: Brian Starkey
Date: Fri Nov 11 2016 - 06:41:50 EST
Hi Gustavo,
On Fri, Nov 11, 2016 at 02:16:09PM +0900, Gustavo Padovan wrote:
From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
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