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Diffstat (limited to 'drivers/gpu/drm/i915/gem/i915_gem_wait.c')
-rw-r--r--drivers/gpu/drm/i915/gem/i915_gem_wait.c278
1 files changed, 278 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_wait.c b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
new file mode 100644
index 000000000000..26ec6579b7cd
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
@@ -0,0 +1,278 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2016 Intel Corporation
+ */
+
+#include <linux/dma-fence-array.h>
+#include <linux/jiffies.h>
+
+#include "gt/intel_engine.h"
+
+#include "i915_gem_ioctls.h"
+#include "i915_gem_object.h"
+
+static long
+i915_gem_object_wait_fence(struct dma_fence *fence,
+ unsigned int flags,
+ long timeout)
+{
+ BUILD_BUG_ON(I915_WAIT_INTERRUPTIBLE != 0x1);
+
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+ return timeout;
+
+ if (dma_fence_is_i915(fence))
+ return i915_request_wait(to_request(fence), flags, timeout);
+
+ return dma_fence_wait_timeout(fence,
+ flags & I915_WAIT_INTERRUPTIBLE,
+ timeout);
+}
+
+static long
+i915_gem_object_wait_reservation(struct reservation_object *resv,
+ unsigned int flags,
+ long timeout)
+{
+ unsigned int seq = __read_seqcount_begin(&resv->seq);
+ struct dma_fence *excl;
+ bool prune_fences = false;
+
+ if (flags & I915_WAIT_ALL) {
+ struct dma_fence **shared;
+ unsigned int count, i;
+ int ret;
+
+ ret = reservation_object_get_fences_rcu(resv,
+ &excl, &count, &shared);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < count; i++) {
+ timeout = i915_gem_object_wait_fence(shared[i],
+ flags, timeout);
+ if (timeout < 0)
+ break;
+
+ dma_fence_put(shared[i]);
+ }
+
+ for (; i < count; i++)
+ dma_fence_put(shared[i]);
+ kfree(shared);
+
+ /*
+ * If both shared fences and an exclusive fence exist,
+ * then by construction the shared fences must be later
+ * than the exclusive fence. If we successfully wait for
+ * all the shared fences, we know that the exclusive fence
+ * must all be signaled. If all the shared fences are
+ * signaled, we can prune the array and recover the
+ * floating references on the fences/requests.
+ */
+ prune_fences = count && timeout >= 0;
+ } else {
+ excl = reservation_object_get_excl_rcu(resv);
+ }
+
+ if (excl && timeout >= 0)
+ timeout = i915_gem_object_wait_fence(excl, flags, timeout);
+
+ dma_fence_put(excl);
+
+ /*
+ * Opportunistically prune the fences iff we know they have *all* been
+ * signaled and that the reservation object has not been changed (i.e.
+ * no new fences have been added).
+ */
+ if (prune_fences && !__read_seqcount_retry(&resv->seq, seq)) {
+ if (reservation_object_trylock(resv)) {
+ if (!__read_seqcount_retry(&resv->seq, seq))
+ reservation_object_add_excl_fence(resv, NULL);
+ reservation_object_unlock(resv);
+ }
+ }
+
+ return timeout;
+}
+
+static void __fence_set_priority(struct dma_fence *fence,
+ const struct i915_sched_attr *attr)
+{
+ struct i915_request *rq;
+ struct intel_engine_cs *engine;
+
+ if (dma_fence_is_signaled(fence) || !dma_fence_is_i915(fence))
+ return;
+
+ rq = to_request(fence);
+ engine = rq->engine;
+
+ local_bh_disable();
+ rcu_read_lock(); /* RCU serialisation for set-wedged protection */
+ if (engine->schedule)
+ engine->schedule(rq, attr);
+ rcu_read_unlock();
+ local_bh_enable(); /* kick the tasklets if queues were reprioritised */
+}
+
+static void fence_set_priority(struct dma_fence *fence,
+ const struct i915_sched_attr *attr)
+{
+ /* Recurse once into a fence-array */
+ if (dma_fence_is_array(fence)) {
+ struct dma_fence_array *array = to_dma_fence_array(fence);
+ int i;
+
+ for (i = 0; i < array->num_fences; i++)
+ __fence_set_priority(array->fences[i], attr);
+ } else {
+ __fence_set_priority(fence, attr);
+ }
+}
+
+int
+i915_gem_object_wait_priority(struct drm_i915_gem_object *obj,
+ unsigned int flags,
+ const struct i915_sched_attr *attr)
+{
+ struct dma_fence *excl;
+
+ if (flags & I915_WAIT_ALL) {
+ struct dma_fence **shared;
+ unsigned int count, i;
+ int ret;
+
+ ret = reservation_object_get_fences_rcu(obj->base.resv,
+ &excl, &count, &shared);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < count; i++) {
+ fence_set_priority(shared[i], attr);
+ dma_fence_put(shared[i]);
+ }
+
+ kfree(shared);
+ } else {
+ excl = reservation_object_get_excl_rcu(obj->base.resv);
+ }
+
+ if (excl) {
+ fence_set_priority(excl, attr);
+ dma_fence_put(excl);
+ }
+ return 0;
+}
+
+/**
+ * Waits for rendering to the object to be completed
+ * @obj: i915 gem object
+ * @flags: how to wait (under a lock, for all rendering or just for writes etc)
+ * @timeout: how long to wait
+ */
+int
+i915_gem_object_wait(struct drm_i915_gem_object *obj,
+ unsigned int flags,
+ long timeout)
+{
+ might_sleep();
+ GEM_BUG_ON(timeout < 0);
+
+ timeout = i915_gem_object_wait_reservation(obj->base.resv,
+ flags, timeout);
+ return timeout < 0 ? timeout : 0;
+}
+
+static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)
+{
+ /* nsecs_to_jiffies64() does not guard against overflow */
+ if (NSEC_PER_SEC % HZ &&
+ div_u64(n, NSEC_PER_SEC) >= MAX_JIFFY_OFFSET / HZ)
+ return MAX_JIFFY_OFFSET;
+
+ return min_t(u64, MAX_JIFFY_OFFSET, nsecs_to_jiffies64(n) + 1);
+}
+
+static unsigned long to_wait_timeout(s64 timeout_ns)
+{
+ if (timeout_ns < 0)
+ return MAX_SCHEDULE_TIMEOUT;
+
+ if (timeout_ns == 0)
+ return 0;
+
+ return nsecs_to_jiffies_timeout(timeout_ns);
+}
+
+/**
+ * i915_gem_wait_ioctl - implements DRM_IOCTL_I915_GEM_WAIT
+ * @dev: drm device pointer
+ * @data: ioctl data blob
+ * @file: drm file pointer
+ *
+ * Returns 0 if successful, else an error is returned with the remaining time in
+ * the timeout parameter.
+ * -ETIME: object is still busy after timeout
+ * -ERESTARTSYS: signal interrupted the wait
+ * -ENONENT: object doesn't exist
+ * Also possible, but rare:
+ * -EAGAIN: incomplete, restart syscall
+ * -ENOMEM: damn
+ * -ENODEV: Internal IRQ fail
+ * -E?: The add request failed
+ *
+ * The wait ioctl with a timeout of 0 reimplements the busy ioctl. With any
+ * non-zero timeout parameter the wait ioctl will wait for the given number of
+ * nanoseconds on an object becoming unbusy. Since the wait itself does so
+ * without holding struct_mutex the object may become re-busied before this
+ * function completes. A similar but shorter * race condition exists in the busy
+ * ioctl
+ */
+int
+i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
+{
+ struct drm_i915_gem_wait *args = data;
+ struct drm_i915_gem_object *obj;
+ ktime_t start;
+ long ret;
+
+ if (args->flags != 0)
+ return -EINVAL;
+
+ obj = i915_gem_object_lookup(file, args->bo_handle);
+ if (!obj)
+ return -ENOENT;
+
+ start = ktime_get();
+
+ ret = i915_gem_object_wait(obj,
+ I915_WAIT_INTERRUPTIBLE |
+ I915_WAIT_PRIORITY |
+ I915_WAIT_ALL,
+ to_wait_timeout(args->timeout_ns));
+
+ if (args->timeout_ns > 0) {
+ args->timeout_ns -= ktime_to_ns(ktime_sub(ktime_get(), start));
+ if (args->timeout_ns < 0)
+ args->timeout_ns = 0;
+
+ /*
+ * Apparently ktime isn't accurate enough and occasionally has a
+ * bit of mismatch in the jiffies<->nsecs<->ktime loop. So patch
+ * things up to make the test happy. We allow up to 1 jiffy.
+ *
+ * This is a regression from the timespec->ktime conversion.
+ */
+ if (ret == -ETIME && !nsecs_to_jiffies(args->timeout_ns))
+ args->timeout_ns = 0;
+
+ /* Asked to wait beyond the jiffie/scheduler precision? */
+ if (ret == -ETIME && args->timeout_ns)
+ ret = -EAGAIN;
+ }
+
+ i915_gem_object_put(obj);
+ return ret;
+}