/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2016 Intel Corporation
*/
#include <linux/dma-fence-array.h>
#include <linux/dma-fence-chain.h>
#include <linux/jiffies.h>
#include "gt/intel_engine.h"
#include "gt/intel_rps.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_timeout(to_request(fence), flags, timeout);
return dma_fence_wait_timeout(fence,
flags & I915_WAIT_INTERRUPTIBLE,
timeout);
}
static void
i915_gem_object_boost(struct dma_resv *resv, unsigned int flags)
{
struct dma_resv_iter cursor;
struct dma_fence *fence;
/*
* Prescan all fences for potential boosting before we begin waiting.
*
* When we wait, we wait on outstanding fences serially. If the
* dma-resv contains a sequence such as 1:1, 1:2 instead of a reduced
* form 1:2, then as we look at each wait in turn we see that each
* request is currently executing and not worthy of boosting. But if
* we only happen to look at the final fence in the sequence (because
* of request coalescing or splitting between read/write arrays by
* the iterator), then we would boost. As such our decision to boost
* or not is delicately balanced on the order we wait on fences.
*
* So instead of looking for boosts sequentially, look for all boosts
* upfront and then wait on the outstanding fences.
*/
dma_resv_iter_begin(&cursor, resv,
dma_resv_usage_rw(flags & I915_WAIT_ALL));
dma_resv_for_each_fence_unlocked(&cursor, fence)
if (dma_fence_is_i915(fence) &&
!i915_request_started(to_request(fence)))
intel_rps_boost(to_request(fence));
dma_resv_iter_end(&cursor);
}
static long
i915_gem_object_wait_reservation(struct dma_resv *resv,
unsigned int flags,
long timeout)
{
struct dma_resv_iter cursor;
struct dma_fence *fence;
long ret = timeout ?: 1;
i915_gem_object_boost(resv, flags);
dma_resv_iter_begin(&cursor, resv,
dma_resv_usage_rw(flags & I915_WAIT_ALL));
dma_resv_for_each_fence_unlocked(&cursor, fence) {
ret = i915_gem_object_wait_fence(fence, flags, timeout);
if (ret <= 0)
break;
if (timeout)
timeout = ret;
}
dma_resv_iter_end(&cursor);
return ret;
}
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;
rcu_read_lock(); /* RCU serialisation for set-wedged protection */
if (engine->sched_engine->schedule)
engine->sched_engine->schedule(rq, attr);
rcu_read_unlock();
}
static inline bool __dma_fence_is_chain(const struct dma_fence *fence)
{
return fence->ops == &dma_fence_chain_ops;
}
void i915_gem_fence_wait_priority(struct dma_fence *fence,
const struct i915_sched_attr *attr)
{
if (dma_fence_is_signaled(fence))
return;
local_bh_disable();
/* 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 if (__dma_fence_is_chain(fence)) {
struct dma_fence *iter;
/* The chain is ordered; if we boost the last, we boost all */
dma_fence_chain_for_each(iter, fence) {
fence_set_priority(to_dma_fence_chain(iter)->fence,
attr);
break;
}
dma_fence_put(iter);
} else {
fence_set_priority(fence, attr);
}
local_bh_enable(); /* kick the tasklets if queues were reprioritised */
}
int
i915_gem_object_wait_priority(struct drm_i915_gem_object *obj,
unsigned int flags,
const struct i915_sched_attr *attr)
{
struct dma_resv_iter cursor;
struct dma_fence *fence;
dma_resv_iter_begin(&cursor, obj->base.resv,
dma_resv_usage_rw(flags & I915_WAIT_ALL));
dma_resv_for_each_fence_unlocked(&cursor, fence)
i915_gem_fence_wait_priority(fence, attr);
dma_resv_iter_end(&cursor);
return 0;
}
/**
* i915_gem_object_wait - 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);
if (timeout < 0)
return timeout;
return !timeout ? -ETIME : 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) != 0 &&
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 jiffy/scheduler precision? */
if (ret == -ETIME && args->timeout_ns)
ret = -EAGAIN;
}
i915_gem_object_put(obj);
return ret;
}
/**
* i915_gem_object_wait_migration - Sync an accelerated migration operation
* @obj: The migrating object.
* @flags: waiting flags. Currently supports only I915_WAIT_INTERRUPTIBLE.
*
* Wait for any pending async migration operation on the object,
* whether it's explicitly (i915_gem_object_migrate()) or implicitly
* (swapin, initial clearing) initiated.
*
* Return: 0 if successful, -ERESTARTSYS if a signal was hit during waiting.
*/
int i915_gem_object_wait_migration(struct drm_i915_gem_object *obj,
unsigned int flags)
{
might_sleep();
return i915_gem_object_wait_moving_fence(obj, !!(flags & I915_WAIT_INTERRUPTIBLE));
}
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