@@ -134,7 +134,10 @@ static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
{
struct dma_buf *dmabuf;
struct reservation_object *resv;
+ struct reservation_object_list *fobj;
+ struct fence *fence_excl;
unsigned long events;
+ unsigned shared_count;
dmabuf = file->private_data;
if (!dmabuf || !dmabuf->resv)
@@ -150,12 +153,18 @@ static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
ww_mutex_lock(&resv->lock, NULL);
- if (resv->fence_excl && (!(events & POLLOUT) ||
- resv->fence_shared_count == 0)) {
+ fobj = resv->fence;
+ if (!fobj)
+ goto out;
+
+ shared_count = fobj->shared_count;
+ fence_excl = resv->fence_excl;
+
+ if (fence_excl && (!(events & POLLOUT) || shared_count == 0)) {
struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl;
unsigned long pevents = POLLIN;
- if (resv->fence_shared_count == 0)
+ if (shared_count == 0)
pevents |= POLLOUT;
spin_lock_irq(&dmabuf->poll.lock);
@@ -167,19 +176,20 @@ static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
spin_unlock_irq(&dmabuf->poll.lock);
if (events & pevents) {
- if (!fence_add_callback(resv->fence_excl,
- &dcb->cb, dma_buf_poll_cb))
+ if (!fence_add_callback(fence_excl, &dcb->cb,
+ dma_buf_poll_cb)) {
events &= ~pevents;
- else
+ } else {
/*
* No callback queued, wake up any additional
* waiters.
*/
dma_buf_poll_cb(NULL, &dcb->cb);
+ }
}
}
- if ((events & POLLOUT) && resv->fence_shared_count > 0) {
+ if ((events & POLLOUT) && shared_count > 0) {
struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
int i;
@@ -194,15 +204,18 @@ static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
if (!(events & POLLOUT))
goto out;
- for (i = 0; i < resv->fence_shared_count; ++i)
- if (!fence_add_callback(resv->fence_shared[i],
- &dcb->cb, dma_buf_poll_cb)) {
+ for (i = 0; i < shared_count; ++i) {
+ struct fence *fence = fobj->shared[i];
+
+ if (!fence_add_callback(fence, &dcb->cb,
+ dma_buf_poll_cb)) {
events &= ~POLLOUT;
break;
}
+ }
/* No callback queued, wake up any additional waiters. */
- if (i == resv->fence_shared_count)
+ if (i == shared_count)
dma_buf_poll_cb(NULL, &dcb->cb);
}
@@ -170,7 +170,7 @@ void release_fence(struct kref *kref)
if (fence->ops->release)
fence->ops->release(fence);
else
- kfree(fence);
+ free_fence(fence);
}
EXPORT_SYMBOL(release_fence);
@@ -448,7 +448,7 @@ static void seqno_release(struct fence *fence)
if (f->ops->release)
f->ops->release(fence);
else
- kfree(f);
+ free_fence(fence);
}
static long seqno_wait(struct fence *fence, bool intr, signed long timeout)
@@ -37,3 +37,157 @@
DEFINE_WW_CLASS(reservation_ww_class);
EXPORT_SYMBOL(reservation_ww_class);
+
+/*
+ * Reserve space to add a shared fence to a reservation_object,
+ * must be called with obj->lock held.
+ */
+int reservation_object_reserve_shared(struct reservation_object *obj)
+{
+ struct reservation_object_list *fobj, *old;
+ u32 max;
+
+ old = reservation_object_get_list(obj);
+
+ if (old && old->shared_max) {
+ if (old->shared_count < old->shared_max) {
+ /* perform an in-place update */
+ kfree(obj->staged);
+ obj->staged = NULL;
+ return 0;
+ }
+ max = old->shared_max * 2;
+ } else
+ max = 4;
+
+ /*
+ * resize obj->staged or allocate if it doesn't exist,
+ * noop if already correct size
+ */
+ fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
+ GFP_KERNEL);
+ if (!fobj)
+ return -ENOMEM;
+
+ obj->staged = fobj;
+ fobj->shared_max = max;
+ return 0;
+}
+EXPORT_SYMBOL(reservation_object_reserve_shared);
+
+static void
+reservation_object_add_shared_inplace(struct reservation_object *obj,
+ struct reservation_object_list *fobj,
+ struct fence *fence)
+{
+ u32 i;
+
+ for (i = 0; i < fobj->shared_count; ++i) {
+ if (fobj->shared[i]->context == fence->context) {
+ struct fence *old_fence = fobj->shared[i];
+
+ fence_get(fence);
+
+ fobj->shared[i] = fence;
+
+ fence_put(old_fence);
+ return;
+ }
+ }
+
+ fence_get(fence);
+ fobj->shared[fobj->shared_count] = fence;
+ /*
+ * make the new fence visible before incrementing
+ * fobj->shared_count
+ */
+ smp_wmb();
+ fobj->shared_count++;
+}
+
+static void
+reservation_object_add_shared_replace(struct reservation_object *obj,
+ struct reservation_object_list *old,
+ struct reservation_object_list *fobj,
+ struct fence *fence)
+{
+ unsigned i;
+
+ fence_get(fence);
+
+ if (!old) {
+ fobj->shared[0] = fence;
+ fobj->shared_count = 1;
+ goto done;
+ }
+
+ /*
+ * no need to bump fence refcounts, rcu_read access
+ * requires the use of kref_get_unless_zero, and the
+ * references from the old struct are carried over to
+ * the new.
+ */
+ fobj->shared_count = old->shared_count;
+
+ for (i = 0; i < old->shared_count; ++i) {
+ if (fence && old->shared[i]->context == fence->context) {
+ fence_put(old->shared[i]);
+ fobj->shared[i] = fence;
+ fence = NULL;
+ } else
+ fobj->shared[i] = old->shared[i];
+ }
+ if (fence)
+ fobj->shared[fobj->shared_count++] = fence;
+
+done:
+ obj->fence = fobj;
+ kfree(old);
+}
+
+/*
+ * Add a fence to a shared slot, obj->lock must be held, and
+ * reservation_object_reserve_shared_fence has been called.
+ */
+void reservation_object_add_shared_fence(struct reservation_object *obj,
+ struct fence *fence)
+{
+ struct reservation_object_list *old, *fobj = obj->staged;
+
+ old = reservation_object_get_list(obj);
+ obj->staged = NULL;
+
+ if (!fobj) {
+ BUG_ON(old->shared_count == old->shared_max);
+ reservation_object_add_shared_inplace(obj, old, fence);
+ } else
+ reservation_object_add_shared_replace(obj, old, fobj, fence);
+}
+EXPORT_SYMBOL(reservation_object_add_shared_fence);
+
+void reservation_object_add_excl_fence(struct reservation_object *obj,
+ struct fence *fence)
+{
+ struct fence *old_fence = obj->fence_excl;
+ struct reservation_object_list *old;
+ u32 i = 0;
+
+ old = reservation_object_get_list(obj);
+ if (old) {
+ i = old->shared_count;
+ old->shared_count = 0;
+ }
+
+ if (fence)
+ fence_get(fence);
+
+ obj->fence_excl = fence;
+
+ /* inplace update, no shared fences */
+ while (i--)
+ fence_put(old->shared[i]);
+
+ if (old_fence)
+ fence_put(old_fence);
+}
+EXPORT_SYMBOL(reservation_object_add_excl_fence);
@@ -31,6 +31,7 @@
#include <linux/kref.h>
#include <linux/sched.h>
#include <linux/printk.h>
+#include <linux/slab.h>
struct fence;
struct fence_ops;
@@ -191,6 +192,11 @@ static inline void fence_get(struct fence *fence)
extern void release_fence(struct kref *kref);
+static inline void free_fence(struct fence *fence)
+{
+ kfree(fence);
+}
+
/**
* fence_put - decreases refcount of the fence
* @fence: [in] fence to reduce refcount of
@@ -45,36 +45,70 @@
extern struct ww_class reservation_ww_class;
+struct reservation_object_list {
+ u32 shared_count, shared_max;
+ struct fence *shared[];
+};
+
struct reservation_object {
struct ww_mutex lock;
struct fence *fence_excl;
- struct fence **fence_shared;
- u32 fence_shared_count, fence_shared_max;
+ struct reservation_object_list *fence;
+ struct reservation_object_list *staged;
};
+#define reservation_object_assert_held(obj) \
+ lockdep_assert_held(&(obj)->lock.base)
+
static inline void
reservation_object_init(struct reservation_object *obj)
{
ww_mutex_init(&obj->lock, &reservation_ww_class);
- obj->fence_shared_count = obj->fence_shared_max = 0;
- obj->fence_shared = NULL;
obj->fence_excl = NULL;
+ obj->fence = NULL;
+ obj->staged = NULL;
}
static inline void
reservation_object_fini(struct reservation_object *obj)
{
int i;
+ struct reservation_object_list *fobj;
+ /*
+ * This object should be dead and all references must have
+ * been released to it.
+ */
if (obj->fence_excl)
fence_put(obj->fence_excl);
- for (i = 0; i < obj->fence_shared_count; ++i)
- fence_put(obj->fence_shared[i]);
- kfree(obj->fence_shared);
+
+ fobj = obj->fence;
+ if (fobj) {
+ for (i = 0; i < fobj->shared_count; ++i)
+ fence_put(fobj->shared[i]);
+
+ kfree(fobj);
+ }
+ kfree(obj->staged);
ww_mutex_destroy(&obj->lock);
}
+static inline struct reservation_object_list *
+reservation_object_get_list(struct reservation_object *obj)
+{
+ reservation_object_assert_held(obj);
+
+ return obj->fence;
+}
+
+int reservation_object_reserve_shared(struct reservation_object *obj);
+void reservation_object_add_shared_fence(struct reservation_object *obj,
+ struct fence *fence);
+
+void reservation_object_add_excl_fence(struct reservation_object *obj,
+ struct fence *fence);
+
#endif /* _LINUX_RESERVATION_H */
@@ -1694,6 +1694,7 @@ int wake_up_state(struct task_struct *p, unsigned int state)
{
return try_to_wake_up(p, state, 0);
}
+EXPORT_SYMBOL(wake_up_state);
/*
* Perform scheduler related setup for a newly forked process p.
Move the list of shared fences to a struct, and return it in reservation_object_get_list(). Add reservation_object_reserve_shared(), which reserves space in the reservation_object for 1 more shared fence. reservation_object_add_shared_fence() and reservation_object_add_excl_fence() are used to assign a new fence to a reservation_object pointer, to complete a reservation. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> --- drivers/base/dma-buf.c | 35 +++++++--- drivers/base/fence.c | 4 + drivers/base/reservation.c | 154 +++++++++++++++++++++++++++++++++++++++++++ include/linux/fence.h | 6 ++ include/linux/reservation.h | 48 +++++++++++-- kernel/sched/core.c | 1 6 files changed, 228 insertions(+), 20 deletions(-)