dma-buf: Rename struct fence to dma_fence
I plan to usurp the short name of struct fence for a core kernel struct,
and so I need to rename the specialised fence/timeline for DMA
operations to make room.
A consensus was reached in
https://lists.freedesktop.org/archives/dri-devel/2016-July/113083.html
that making clear this fence applies to DMA operations was a good thing.
Since then the patch has grown a bit as usage increases, so hopefully it
remains a good thing!
(v2...: rebase, rerun spatch)
v3: Compile on msm, spotted a manual fixup that I broke.
v4: Try again for msm, sorry Daniel
coccinelle script:
@@
@@
- struct fence
+ struct dma_fence
@@
@@
- struct fence_ops
+ struct dma_fence_ops
@@
@@
- struct fence_cb
+ struct dma_fence_cb
@@
@@
- struct fence_array
+ struct dma_fence_array
@@
@@
- enum fence_flag_bits
+ enum dma_fence_flag_bits
@@
@@
(
- fence_init
+ dma_fence_init
|
- fence_release
+ dma_fence_release
|
- fence_free
+ dma_fence_free
|
- fence_get
+ dma_fence_get
|
- fence_get_rcu
+ dma_fence_get_rcu
|
- fence_put
+ dma_fence_put
|
- fence_signal
+ dma_fence_signal
|
- fence_signal_locked
+ dma_fence_signal_locked
|
- fence_default_wait
+ dma_fence_default_wait
|
- fence_add_callback
+ dma_fence_add_callback
|
- fence_remove_callback
+ dma_fence_remove_callback
|
- fence_enable_sw_signaling
+ dma_fence_enable_sw_signaling
|
- fence_is_signaled_locked
+ dma_fence_is_signaled_locked
|
- fence_is_signaled
+ dma_fence_is_signaled
|
- fence_is_later
+ dma_fence_is_later
|
- fence_later
+ dma_fence_later
|
- fence_wait_timeout
+ dma_fence_wait_timeout
|
- fence_wait_any_timeout
+ dma_fence_wait_any_timeout
|
- fence_wait
+ dma_fence_wait
|
- fence_context_alloc
+ dma_fence_context_alloc
|
- fence_array_create
+ dma_fence_array_create
|
- to_fence_array
+ to_dma_fence_array
|
- fence_is_array
+ dma_fence_is_array
|
- trace_fence_emit
+ trace_dma_fence_emit
|
- FENCE_TRACE
+ DMA_FENCE_TRACE
|
- FENCE_WARN
+ DMA_FENCE_WARN
|
- FENCE_ERR
+ DMA_FENCE_ERR
)
(
...
)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
new file mode 100644
index 0000000..3a7bf00
--- /dev/null
+++ b/drivers/dma-buf/dma-fence.c
@@ -0,0 +1,537 @@
+/*
+ * Fence mechanism for dma-buf and to allow for asynchronous dma access
+ *
+ * Copyright (C) 2012 Canonical Ltd
+ * Copyright (C) 2012 Texas Instruments
+ *
+ * Authors:
+ * Rob Clark <robdclark@gmail.com>
+ * Maarten Lankhorst <maarten.lankhorst@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/atomic.h>
+#include <linux/dma-fence.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/dma_fence.h>
+
+EXPORT_TRACEPOINT_SYMBOL(dma_fence_annotate_wait_on);
+EXPORT_TRACEPOINT_SYMBOL(dma_fence_emit);
+
+/*
+ * fence context counter: each execution context should have its own
+ * fence context, this allows checking if fences belong to the same
+ * context or not. One device can have multiple separate contexts,
+ * and they're used if some engine can run independently of another.
+ */
+static atomic64_t dma_fence_context_counter = ATOMIC64_INIT(0);
+
+/**
+ * dma_fence_context_alloc - allocate an array of fence contexts
+ * @num: [in] amount of contexts to allocate
+ *
+ * This function will return the first index of the number of fences allocated.
+ * The fence context is used for setting fence->context to a unique number.
+ */
+u64 dma_fence_context_alloc(unsigned num)
+{
+ BUG_ON(!num);
+ return atomic64_add_return(num, &dma_fence_context_counter) - num;
+}
+EXPORT_SYMBOL(dma_fence_context_alloc);
+
+/**
+ * dma_fence_signal_locked - signal completion of a fence
+ * @fence: the fence to signal
+ *
+ * Signal completion for software callbacks on a fence, this will unblock
+ * dma_fence_wait() calls and run all the callbacks added with
+ * dma_fence_add_callback(). Can be called multiple times, but since a fence
+ * can only go from unsignaled to signaled state, it will only be effective
+ * the first time.
+ *
+ * Unlike dma_fence_signal, this function must be called with fence->lock held.
+ */
+int dma_fence_signal_locked(struct dma_fence *fence)
+{
+ struct dma_fence_cb *cur, *tmp;
+ int ret = 0;
+
+ lockdep_assert_held(fence->lock);
+
+ if (WARN_ON(!fence))
+ return -EINVAL;
+
+ if (!ktime_to_ns(fence->timestamp)) {
+ fence->timestamp = ktime_get();
+ smp_mb__before_atomic();
+ }
+
+ if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
+ ret = -EINVAL;
+
+ /*
+ * we might have raced with the unlocked dma_fence_signal,
+ * still run through all callbacks
+ */
+ } else
+ trace_dma_fence_signaled(fence);
+
+ list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
+ list_del_init(&cur->node);
+ cur->func(fence, cur);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(dma_fence_signal_locked);
+
+/**
+ * dma_fence_signal - signal completion of a fence
+ * @fence: the fence to signal
+ *
+ * Signal completion for software callbacks on a fence, this will unblock
+ * dma_fence_wait() calls and run all the callbacks added with
+ * dma_fence_add_callback(). Can be called multiple times, but since a fence
+ * can only go from unsignaled to signaled state, it will only be effective
+ * the first time.
+ */
+int dma_fence_signal(struct dma_fence *fence)
+{
+ unsigned long flags;
+
+ if (!fence)
+ return -EINVAL;
+
+ if (!ktime_to_ns(fence->timestamp)) {
+ fence->timestamp = ktime_get();
+ smp_mb__before_atomic();
+ }
+
+ if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+ return -EINVAL;
+
+ trace_dma_fence_signaled(fence);
+
+ if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) {
+ struct dma_fence_cb *cur, *tmp;
+
+ spin_lock_irqsave(fence->lock, flags);
+ list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
+ list_del_init(&cur->node);
+ cur->func(fence, cur);
+ }
+ spin_unlock_irqrestore(fence->lock, flags);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(dma_fence_signal);
+
+/**
+ * dma_fence_wait_timeout - sleep until the fence gets signaled
+ * or until timeout elapses
+ * @fence: [in] the fence to wait on
+ * @intr: [in] if true, do an interruptible wait
+ * @timeout: [in] timeout value in jiffies, or MAX_SCHEDULE_TIMEOUT
+ *
+ * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or the
+ * remaining timeout in jiffies on success. Other error values may be
+ * returned on custom implementations.
+ *
+ * Performs a synchronous wait on this fence. It is assumed the caller
+ * directly or indirectly (buf-mgr between reservation and committing)
+ * holds a reference to the fence, otherwise the fence might be
+ * freed before return, resulting in undefined behavior.
+ */
+signed long
+dma_fence_wait_timeout(struct dma_fence *fence, bool intr, signed long timeout)
+{
+ signed long ret;
+
+ if (WARN_ON(timeout < 0))
+ return -EINVAL;
+
+ if (timeout == 0)
+ return dma_fence_is_signaled(fence);
+
+ trace_dma_fence_wait_start(fence);
+ ret = fence->ops->wait(fence, intr, timeout);
+ trace_dma_fence_wait_end(fence);
+ return ret;
+}
+EXPORT_SYMBOL(dma_fence_wait_timeout);
+
+void dma_fence_release(struct kref *kref)
+{
+ struct dma_fence *fence =
+ container_of(kref, struct dma_fence, refcount);
+
+ trace_dma_fence_destroy(fence);
+
+ BUG_ON(!list_empty(&fence->cb_list));
+
+ if (fence->ops->release)
+ fence->ops->release(fence);
+ else
+ dma_fence_free(fence);
+}
+EXPORT_SYMBOL(dma_fence_release);
+
+void dma_fence_free(struct dma_fence *fence)
+{
+ kfree_rcu(fence, rcu);
+}
+EXPORT_SYMBOL(dma_fence_free);
+
+/**
+ * dma_fence_enable_sw_signaling - enable signaling on fence
+ * @fence: [in] the fence to enable
+ *
+ * this will request for sw signaling to be enabled, to make the fence
+ * complete as soon as possible
+ */
+void dma_fence_enable_sw_signaling(struct dma_fence *fence)
+{
+ unsigned long flags;
+
+ if (!test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
+ &fence->flags) &&
+ !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
+ trace_dma_fence_enable_signal(fence);
+
+ spin_lock_irqsave(fence->lock, flags);
+
+ if (!fence->ops->enable_signaling(fence))
+ dma_fence_signal_locked(fence);
+
+ spin_unlock_irqrestore(fence->lock, flags);
+ }
+}
+EXPORT_SYMBOL(dma_fence_enable_sw_signaling);
+
+/**
+ * dma_fence_add_callback - add a callback to be called when the fence
+ * is signaled
+ * @fence: [in] the fence to wait on
+ * @cb: [in] the callback to register
+ * @func: [in] the function to call
+ *
+ * cb will be initialized by dma_fence_add_callback, no initialization
+ * by the caller is required. Any number of callbacks can be registered
+ * to a fence, but a callback can only be registered to one fence at a time.
+ *
+ * Note that the callback can be called from an atomic context. If
+ * fence is already signaled, this function will return -ENOENT (and
+ * *not* call the callback)
+ *
+ * Add a software callback to the fence. Same restrictions apply to
+ * refcount as it does to dma_fence_wait, however the caller doesn't need to
+ * keep a refcount to fence afterwards: when software access is enabled,
+ * the creator of the fence is required to keep the fence alive until
+ * after it signals with dma_fence_signal. The callback itself can be called
+ * from irq context.
+ *
+ */
+int dma_fence_add_callback(struct dma_fence *fence, struct dma_fence_cb *cb,
+ dma_fence_func_t func)
+{
+ unsigned long flags;
+ int ret = 0;
+ bool was_set;
+
+ if (WARN_ON(!fence || !func))
+ return -EINVAL;
+
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
+ INIT_LIST_HEAD(&cb->node);
+ return -ENOENT;
+ }
+
+ spin_lock_irqsave(fence->lock, flags);
+
+ was_set = test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
+ &fence->flags);
+
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+ ret = -ENOENT;
+ else if (!was_set) {
+ trace_dma_fence_enable_signal(fence);
+
+ if (!fence->ops->enable_signaling(fence)) {
+ dma_fence_signal_locked(fence);
+ ret = -ENOENT;
+ }
+ }
+
+ if (!ret) {
+ cb->func = func;
+ list_add_tail(&cb->node, &fence->cb_list);
+ } else
+ INIT_LIST_HEAD(&cb->node);
+ spin_unlock_irqrestore(fence->lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(dma_fence_add_callback);
+
+/**
+ * dma_fence_remove_callback - remove a callback from the signaling list
+ * @fence: [in] the fence to wait on
+ * @cb: [in] the callback to remove
+ *
+ * Remove a previously queued callback from the fence. This function returns
+ * true if the callback is successfully removed, or false if the fence has
+ * already been signaled.
+ *
+ * *WARNING*:
+ * Cancelling a callback should only be done if you really know what you're
+ * doing, since deadlocks and race conditions could occur all too easily. For
+ * this reason, it should only ever be done on hardware lockup recovery,
+ * with a reference held to the fence.
+ */
+bool
+dma_fence_remove_callback(struct dma_fence *fence, struct dma_fence_cb *cb)
+{
+ unsigned long flags;
+ bool ret;
+
+ spin_lock_irqsave(fence->lock, flags);
+
+ ret = !list_empty(&cb->node);
+ if (ret)
+ list_del_init(&cb->node);
+
+ spin_unlock_irqrestore(fence->lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(dma_fence_remove_callback);
+
+struct default_wait_cb {
+ struct dma_fence_cb base;
+ struct task_struct *task;
+};
+
+static void
+dma_fence_default_wait_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
+{
+ struct default_wait_cb *wait =
+ container_of(cb, struct default_wait_cb, base);
+
+ wake_up_state(wait->task, TASK_NORMAL);
+}
+
+/**
+ * dma_fence_default_wait - default sleep until the fence gets signaled
+ * or until timeout elapses
+ * @fence: [in] the fence to wait on
+ * @intr: [in] if true, do an interruptible wait
+ * @timeout: [in] timeout value in jiffies, or MAX_SCHEDULE_TIMEOUT
+ *
+ * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or the
+ * remaining timeout in jiffies on success.
+ */
+signed long
+dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
+{
+ struct default_wait_cb cb;
+ unsigned long flags;
+ signed long ret = timeout;
+ bool was_set;
+
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+ return timeout;
+
+ spin_lock_irqsave(fence->lock, flags);
+
+ if (intr && signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ goto out;
+ }
+
+ was_set = test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
+ &fence->flags);
+
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+ goto out;
+
+ if (!was_set) {
+ trace_dma_fence_enable_signal(fence);
+
+ if (!fence->ops->enable_signaling(fence)) {
+ dma_fence_signal_locked(fence);
+ goto out;
+ }
+ }
+
+ cb.base.func = dma_fence_default_wait_cb;
+ cb.task = current;
+ list_add(&cb.base.node, &fence->cb_list);
+
+ while (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) && ret > 0) {
+ if (intr)
+ __set_current_state(TASK_INTERRUPTIBLE);
+ else
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ spin_unlock_irqrestore(fence->lock, flags);
+
+ ret = schedule_timeout(ret);
+
+ spin_lock_irqsave(fence->lock, flags);
+ if (ret > 0 && intr && signal_pending(current))
+ ret = -ERESTARTSYS;
+ }
+
+ if (!list_empty(&cb.base.node))
+ list_del(&cb.base.node);
+ __set_current_state(TASK_RUNNING);
+
+out:
+ spin_unlock_irqrestore(fence->lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(dma_fence_default_wait);
+
+static bool
+dma_fence_test_signaled_any(struct dma_fence **fences, uint32_t count)
+{
+ int i;
+
+ for (i = 0; i < count; ++i) {
+ struct dma_fence *fence = fences[i];
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+ return true;
+ }
+ return false;
+}
+
+/**
+ * dma_fence_wait_any_timeout - sleep until any fence gets signaled
+ * or until timeout elapses
+ * @fences: [in] array of fences to wait on
+ * @count: [in] number of fences to wait on
+ * @intr: [in] if true, do an interruptible wait
+ * @timeout: [in] timeout value in jiffies, or MAX_SCHEDULE_TIMEOUT
+ *
+ * Returns -EINVAL on custom fence wait implementation, -ERESTARTSYS if
+ * interrupted, 0 if the wait timed out, or the remaining timeout in jiffies
+ * on success.
+ *
+ * Synchronous waits for the first fence in the array to be signaled. The
+ * caller needs to hold a reference to all fences in the array, otherwise a
+ * fence might be freed before return, resulting in undefined behavior.
+ */
+signed long
+dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count,
+ bool intr, signed long timeout)
+{
+ struct default_wait_cb *cb;
+ signed long ret = timeout;
+ unsigned i;
+
+ if (WARN_ON(!fences || !count || timeout < 0))
+ return -EINVAL;
+
+ if (timeout == 0) {
+ for (i = 0; i < count; ++i)
+ if (dma_fence_is_signaled(fences[i]))
+ return 1;
+
+ return 0;
+ }
+
+ cb = kcalloc(count, sizeof(struct default_wait_cb), GFP_KERNEL);
+ if (cb == NULL) {
+ ret = -ENOMEM;
+ goto err_free_cb;
+ }
+
+ for (i = 0; i < count; ++i) {
+ struct dma_fence *fence = fences[i];
+
+ if (fence->ops->wait != dma_fence_default_wait) {
+ ret = -EINVAL;
+ goto fence_rm_cb;
+ }
+
+ cb[i].task = current;
+ if (dma_fence_add_callback(fence, &cb[i].base,
+ dma_fence_default_wait_cb)) {
+ /* This fence is already signaled */
+ goto fence_rm_cb;
+ }
+ }
+
+ while (ret > 0) {
+ if (intr)
+ set_current_state(TASK_INTERRUPTIBLE);
+ else
+ set_current_state(TASK_UNINTERRUPTIBLE);
+
+ if (dma_fence_test_signaled_any(fences, count))
+ break;
+
+ ret = schedule_timeout(ret);
+
+ if (ret > 0 && intr && signal_pending(current))
+ ret = -ERESTARTSYS;
+ }
+
+ __set_current_state(TASK_RUNNING);
+
+fence_rm_cb:
+ while (i-- > 0)
+ dma_fence_remove_callback(fences[i], &cb[i].base);
+
+err_free_cb:
+ kfree(cb);
+
+ return ret;
+}
+EXPORT_SYMBOL(dma_fence_wait_any_timeout);
+
+/**
+ * dma_fence_init - Initialize a custom fence.
+ * @fence: [in] the fence to initialize
+ * @ops: [in] the dma_fence_ops for operations on this fence
+ * @lock: [in] the irqsafe spinlock to use for locking this fence
+ * @context: [in] the execution context this fence is run on
+ * @seqno: [in] a linear increasing sequence number for this context
+ *
+ * Initializes an allocated fence, the caller doesn't have to keep its
+ * refcount after committing with this fence, but it will need to hold a
+ * refcount again if dma_fence_ops.enable_signaling gets called. This can
+ * be used for other implementing other types of fence.
+ *
+ * context and seqno are used for easy comparison between fences, allowing
+ * to check which fence is later by simply using dma_fence_later.
+ */
+void
+dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
+ spinlock_t *lock, u64 context, unsigned seqno)
+{
+ BUG_ON(!lock);
+ BUG_ON(!ops || !ops->wait || !ops->enable_signaling ||
+ !ops->get_driver_name || !ops->get_timeline_name);
+
+ kref_init(&fence->refcount);
+ fence->ops = ops;
+ INIT_LIST_HEAD(&fence->cb_list);
+ fence->lock = lock;
+ fence->context = context;
+ fence->seqno = seqno;
+ fence->flags = 0UL;
+
+ trace_dma_fence_init(fence);
+}
+EXPORT_SYMBOL(dma_fence_init);
