Move the list of shared fences to a struct, and return it in reservation_object_get_list(). Add reservation_object_get_excl to get the exclusive fence.
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
Changes since v1: - Add reservation_object_get_excl, reorder code a bit. --- Documentation/DocBook/device-drivers.tmpl | 1 drivers/dma-buf/dma-buf.c | 35 ++++--- drivers/dma-buf/reservation.c | 156 +++++++++++++++++++++++++++++ include/linux/reservation.h | 56 +++++++++- 4 files changed, 229 insertions(+), 19 deletions(-)
diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl index ed0ef00cd7bc..dd3f278faa8a 100644 --- a/Documentation/DocBook/device-drivers.tmpl +++ b/Documentation/DocBook/device-drivers.tmpl @@ -133,6 +133,7 @@ X!Edrivers/base/interface.c !Edrivers/dma-buf/seqno-fence.c !Iinclude/linux/fence.h !Iinclude/linux/seqno-fence.h +!Edrivers/dma-buf/reservation.c !Iinclude/linux/reservation.h !Edrivers/base/dma-coherent.c !Edrivers/base/dma-mapping.c diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 25e8c4165936..cb8379dfeed5 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -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); }
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index a73fbf3b8e56..e6166723a9ae 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2012-2013 Canonical Ltd + * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst) * * Based on bo.c which bears the following copyright notice, * but is dual licensed: @@ -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; + } else + 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); diff --git a/include/linux/reservation.h b/include/linux/reservation.h index f3f57460a205..2affe67dea6e 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -45,36 +45,78 @@
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; +} + +static inline struct fence * +reservation_object_get_excl(struct reservation_object *obj) +{ + reservation_object_assert_held(obj); + + return obj->fence_excl; +} + +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 */