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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>
This commit is contained in:
Erik Gilling 2013-02-28 16:43:10 -08:00 committed by Greg Kroah-Hartman
parent c6f668ce63
commit 01544170e1
2 changed files with 51 additions and 8 deletions
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54
drivers/staging/android/sync.c
View File

@ -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;
}

5
drivers/staging/android/sync.h
View File

@ -16,6 +16,7 @@
#include <linux/types.h>
#ifdef __KERNEL__
#include <linux/kref.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/spinlock.h>
@ -109,6 +110,7 @@ struct sync_timeline {
* @parent: sync_timeline to which this sync_pt belongs
* @child_list: membership in sync_timeline.child_list_head
* @active_list: membership in sync_timeline.active_list_head
* @signaled_list: membership in temorary signaled_list on stack
* @fence: sync_fence to which the sync_pt belongs
* @pt_list: membership in sync_fence.pt_list_head
* @status: 1: signaled, 0:active, <0: error
@ -120,6 +122,7 @@ struct sync_pt {
struct list_head child_list;
struct list_head active_list;
struct list_head signaled_list;
struct sync_fence *fence;
struct list_head pt_list;
@ -133,6 +136,7 @@ struct sync_pt {
/**
* struct sync_fence - sync fence
* @file: file representing this fence
* @kref: referenace count on fence.
* @name: name of sync_fence. Useful for debugging
* @pt_list_head: list of sync_pts in ths fence. immutable once fence
* is created
@ -145,6 +149,7 @@ struct sync_pt {
*/
struct sync_fence {
struct file *file;
struct kref kref;
char name[32];
/* this list is immutable once the fence is created */