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author | Erik Gilling | 2013-03-01 01:43:10 +0100 |
---|---|---|
committer | Greg Kroah-Hartman | 2013-03-04 10:44:07 +0100 |
commit | 01544170e1959dd261ceec6413674a528221669b (patch) | |
tree | 003fb10b436e06443ccbaab29b719aba549a3919 /drivers/staging/android/sync.c | |
parent | staging: sync: Optimize fence merges (diff) | |
download | kernel-qcow2-linux-01544170e1959dd261ceec6413674a528221669b.tar.gz kernel-qcow2-linux-01544170e1959dd261ceec6413674a528221669b.tar.xz kernel-qcow2-linux-01544170e1959dd261ceec6413674a528221669b.zip |
staging: sync: Add internal refcounting to fences
If a fence is released while a timeline that one of it's pts is on is being
signaled, it is possible for that fence to be deleted before it is signaled.
This patch adds a refcount for internal references such as signaled pt
processing.
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Erik Gilling <konkers@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/android/sync.c')
-rw-r--r-- | drivers/staging/android/sync.c | 54 |
1 files changed, 46 insertions, 8 deletions
diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c index 6cb7c883fad0..7d4e9aaa5368 100644 --- a/drivers/staging/android/sync.c +++ b/drivers/staging/android/sync.c @@ -30,6 +30,7 @@ static void sync_fence_signal_pt(struct sync_pt *pt); static int _sync_pt_has_signaled(struct sync_pt *pt); +static void sync_fence_free(struct kref *kref); static LIST_HEAD(sync_timeline_list_head); static DEFINE_SPINLOCK(sync_timeline_list_lock); @@ -113,7 +114,7 @@ static void sync_timeline_remove_pt(struct sync_pt *pt) { struct sync_timeline *obj = pt->parent; unsigned long flags; - bool needs_freeing; + bool needs_freeing = false; spin_lock_irqsave(&obj->active_list_lock, flags); if (!list_empty(&pt->active_list)) @@ -121,8 +122,11 @@ static void sync_timeline_remove_pt(struct sync_pt *pt) spin_unlock_irqrestore(&obj->active_list_lock, flags); spin_lock_irqsave(&obj->child_list_lock, flags); - list_del(&pt->child_list); - needs_freeing = obj->destroyed && list_empty(&obj->child_list_head); + if (!list_empty(&pt->child_list)) { + list_del_init(&pt->child_list); + needs_freeing = obj->destroyed && + list_empty(&obj->child_list_head); + } spin_unlock_irqrestore(&obj->child_list_lock, flags); if (needs_freeing) @@ -141,18 +145,22 @@ void sync_timeline_signal(struct sync_timeline *obj) struct sync_pt *pt = container_of(pos, struct sync_pt, active_list); - if (_sync_pt_has_signaled(pt)) - list_move(pos, &signaled_pts); + if (_sync_pt_has_signaled(pt)) { + list_del_init(pos); + list_add(&pt->signaled_list, &signaled_pts); + kref_get(&pt->fence->kref); + } } spin_unlock_irqrestore(&obj->active_list_lock, flags); list_for_each_safe(pos, n, &signaled_pts) { struct sync_pt *pt = - container_of(pos, struct sync_pt, active_list); + container_of(pos, struct sync_pt, signaled_list); list_del_init(pos); sync_fence_signal_pt(pt); + kref_put(&pt->fence->kref, sync_fence_free); } } EXPORT_SYMBOL(sync_timeline_signal); @@ -253,6 +261,7 @@ static struct sync_fence *sync_fence_alloc(const char *name) if (fence->file == NULL) goto err; + kref_init(&fence->kref); strlcpy(fence->name, name, sizeof(fence->name)); INIT_LIST_HEAD(&fence->pt_list_head); @@ -362,6 +371,16 @@ static int sync_fence_merge_pts(struct sync_fence *dst, struct sync_fence *src) return 0; } +static void sync_fence_detach_pts(struct sync_fence *fence) +{ + struct list_head *pos, *n; + + list_for_each_safe(pos, n, &fence->pt_list_head) { + struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list); + sync_timeline_remove_pt(pt); + } +} + static void sync_fence_free_pts(struct sync_fence *fence) { struct list_head *pos, *n; @@ -565,18 +584,37 @@ int sync_fence_wait(struct sync_fence *fence, long timeout) } EXPORT_SYMBOL(sync_fence_wait); +static void sync_fence_free(struct kref *kref) +{ + struct sync_fence *fence = container_of(kref, struct sync_fence, kref); + + sync_fence_free_pts(fence); + + kfree(fence); +} + static int sync_fence_release(struct inode *inode, struct file *file) { struct sync_fence *fence = file->private_data; unsigned long flags; + /* + * We need to remove all ways to access this fence before droping + * our ref. + * + * start with its membership in the global fence list + */ spin_lock_irqsave(&sync_fence_list_lock, flags); list_del(&fence->sync_fence_list); spin_unlock_irqrestore(&sync_fence_list_lock, flags); - sync_fence_free_pts(fence); + /* + * remove its pts from their parents so that sync_timeline_signal() + * can't reference the fence. + */ + sync_fence_detach_pts(fence); - kfree(fence); + kref_put(&fence->kref, sync_fence_free); return 0; } |