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dma-buf/sw-sync: Fix locking around sync_timeline lists 

The sync_pt were not adding themselves atomically to the timeline lists,
corruption imminent.  Only a single list is required to track the
unsignaled sync_pt, so reduce it and rename the lock more appropriately
along with using idiomatic names to distinguish a list from links along
it.

v2: Prevent spinlock recursion on free during create (next patch) and
fixup crossref in kerneldoc

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170629210532.5617-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2017-06-29 22:05:32 +01:00 committed by Gustavo Padovan
parent 3b52ce44e7
commit d3862e44da
3 changed files with 31 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/dma-buf/sw_sync.c
View File

@ -96,9 +96,8 @@ static struct sync_timeline *sync_timeline_create(const char *name)
obj->context = dma_fence_context_alloc(1);
strlcpy(obj->name, name, sizeof(obj->name));
INIT_LIST_HEAD(&obj->child_list_head);
INIT_LIST_HEAD(&obj->active_list_head);
spin_lock_init(&obj->child_list_lock);
INIT_LIST_HEAD(&obj->pt_list);
spin_lock_init(&obj->lock);
sync_timeline_debug_add(obj);
@ -139,17 +138,15 @@ static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
trace_sync_timeline(obj);
spin_lock_irq(&obj->child_list_lock);
spin_lock_irq(&obj->lock);
obj->value += inc;
list_for_each_entry_safe(pt, next, &obj->active_list_head,
active_list) {
list_for_each_entry_safe(pt, next, &obj->pt_list, link)
if (dma_fence_is_signaled_locked(&pt->base))
list_del_init(&pt->active_list);
}
list_del_init(&pt->link);
spin_unlock_irq(&obj->child_list_lock);
spin_unlock_irq(&obj->lock);
}
/**
@ -171,15 +168,15 @@ static struct sync_pt *sync_pt_create(struct sync_timeline *obj,
if (!pt)
return NULL;
spin_lock_irq(&obj->child_list_lock);
sync_timeline_get(obj);
dma_fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock,
dma_fence_init(&pt->base, &timeline_fence_ops, &obj->lock,
obj->context, value);
list_add_tail(&pt->child_list, &obj->child_list_head);
INIT_LIST_HEAD(&pt->active_list);
INIT_LIST_HEAD(&pt->link);
spin_unlock_irq(&obj->child_list_lock);
spin_lock_irq(&obj->lock);
if (!dma_fence_is_signaled_locked(&pt->base))
list_add_tail(&pt->link, &obj->pt_list);
spin_unlock_irq(&obj->lock);
return pt;
}
@ -200,15 +197,15 @@ static void timeline_fence_release(struct dma_fence *fence)
{
struct sync_pt *pt = dma_fence_to_sync_pt(fence);
struct sync_timeline *parent = dma_fence_parent(fence);
unsigned long flags;
spin_lock_irqsave(fence->lock, flags);
if (!list_empty(&pt->link)) {
unsigned long flags;
list_del(&pt->child_list);
if (!list_empty(&pt->active_list))
list_del(&pt->active_list);
spin_unlock_irqrestore(fence->lock, flags);
spin_lock_irqsave(fence->lock, flags);
if (!list_empty(&pt->link))
list_del(&pt->link);
spin_unlock_irqrestore(fence->lock, flags);
}
sync_timeline_put(parent);
dma_fence_free(fence);
@ -223,13 +220,6 @@ static bool timeline_fence_signaled(struct dma_fence *fence)
static bool timeline_fence_enable_signaling(struct dma_fence *fence)
{
struct sync_pt *pt = dma_fence_to_sync_pt(fence);
struct sync_timeline *parent = dma_fence_parent(fence);
if (timeline_fence_signaled(fence))
return false;
list_add_tail(&pt->active_list, &parent->active_list_head);
return true;
}

9
drivers/dma-buf/sync_debug.c
View File

@ -119,13 +119,12 @@ static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
seq_printf(s, "%s: %d\n", obj->name, obj->value);
spin_lock_irq(&obj->child_list_lock);
list_for_each(pos, &obj->child_list_head) {
struct sync_pt *pt =
container_of(pos, struct sync_pt, child_list);
spin_lock_irq(&obj->lock);
list_for_each(pos, &obj->pt_list) {
struct sync_pt *pt = container_of(pos, struct sync_pt, link);
sync_print_fence(s, &pt->base, false);
}
spin_unlock_irq(&obj->child_list_lock);
spin_unlock_irq(&obj->lock);
}
static void sync_print_sync_file(struct seq_file *s,

21
drivers/dma-buf/sync_debug.h
View File

@ -24,42 +24,37 @@
* struct sync_timeline - sync object
* @kref: reference count on fence.
* @name: name of the sync_timeline. Useful for debugging
* @child_list_head: list of children sync_pts for this sync_timeline
* @child_list_lock: lock protecting @child_list_head and fence.status
* @active_list_head: list of active (unsignaled/errored) sync_pts
* @lock: lock protecting @pt_list and @value
* @pt_list: list of active (unsignaled/errored) sync_pts
* @sync_timeline_list: membership in global sync_timeline_list
*/
struct sync_timeline {
struct kref kref;
char name[32];
/* protected by child_list_lock */
/* protected by lock */
u64 context;
int value;
struct list_head child_list_head;
spinlock_t child_list_lock;
struct list_head active_list_head;
struct list_head pt_list;
spinlock_t lock;
struct list_head sync_timeline_list;
};
static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
{
return container_of(fence->lock, struct sync_timeline, child_list_lock);
return container_of(fence->lock, struct sync_timeline, lock);
}
/**
* struct sync_pt - sync_pt object
* @base: base fence object
* @child_list: sync timeline child's list
* @active_list: sync timeline active child's list
* @link: link on the sync timeline's list
*/
struct sync_pt {
struct dma_fence base;
struct list_head child_list;
struct list_head active_list;
struct list_head link;
};
#ifdef CONFIG_SW_SYNC