[Intel-gfx] [PATCH 20/25] drm/i915: Multi-BB execbuf

John Harrison john.c.harrison at intel.com
Thu Oct 14 18:27:52 UTC 2021


On 10/14/2021 10:20, Matthew Brost wrote:
> Allow multiple batch buffers to be submitted in a single execbuf IOCTL
> after a context has been configured with the 'set_parallel' extension.
> The number batches is implicit based on the contexts configuration.
>
> This is implemented with a series of loops. First a loop is used to find
> all the batches, a loop to pin all the HW contexts, a loop to create all
> the requests, a loop to submit (emit BB start, etc...) all the requests,
> a loop to tie the requests to the VMAs they touch, and finally a loop to
> commit the requests to the backend.
>
> A composite fence is also created for the generated requests to return
> to the user and to stick in dma resv slots.
>
> No behavior from the existing IOCTL should be changed aside from when
> throttling because the ring for a context is full. In this situation,
> i915 will now wait while holding the object locks. This change was done
> because the code is much simpler to wait while holding the locks and we
> believe there isn't a huge benefit of dropping these locks. If this
> proves false we can restructure the code to drop the locks during the
> wait.
>
> IGT: https://patchwork.freedesktop.org/patch/447008/?series=93071&rev=1
> media UMD: https://github.com/intel/media-driver/pull/1252
>
> v2:
>   (Matthew Brost)
>    - Return proper error value if i915_request_create fails
> v3:
>   (John Harrison)
>    - Add comment explaining create / add order loops + locking
>    - Update commit message explaining different in IOCTL behavior
>    - Line wrap some comments
>    - eb_add_request returns void
>    - Return -EINVAL rather triggering BUG_ON if cmd parser used
>   (Checkpatch)
>    - Check eb->batch_len[*current_batch]
> v4:
>   (CI)
>    - Set batch len if passed if via execbuf args
>    - Call __i915_request_skip after __i915_request_commit
>   (Kernel test robot)
>    - Initialize rq to NULL in eb_pin_timeline
> v5:
>   (John Harrison)
>    - Fix typo in comments near bb order loops
>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
Reviewed-by: John Harrison <John.C.Harrison at Intel.com>

> ---
>   .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 783 ++++++++++++------
>   drivers/gpu/drm/i915/gt/intel_context.h       |   8 +-
>   drivers/gpu/drm/i915/gt/intel_context_types.h |  10 +
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c |   2 +
>   drivers/gpu/drm/i915/i915_request.h           |   9 +
>   drivers/gpu/drm/i915/i915_vma.c               |  21 +-
>   drivers/gpu/drm/i915/i915_vma.h               |  13 +-
>   7 files changed, 595 insertions(+), 251 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index c75afc8784e3..fc30856e81fa 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -246,17 +246,25 @@ struct i915_execbuffer {
>   	struct drm_i915_gem_exec_object2 *exec; /** ioctl execobj[] */
>   	struct eb_vma *vma;
>   
> -	struct intel_engine_cs *engine; /** engine to queue the request to */
> +	struct intel_gt *gt; /* gt for the execbuf */
>   	struct intel_context *context; /* logical state for the request */
>   	struct i915_gem_context *gem_context; /** caller's context */
>   
> -	struct i915_request *request; /** our request to build */
> -	struct eb_vma *batch; /** identity of the batch obj/vma */
> +	/** our requests to build */
> +	struct i915_request *requests[MAX_ENGINE_INSTANCE + 1];
> +	/** identity of the batch obj/vma */
> +	struct eb_vma *batches[MAX_ENGINE_INSTANCE + 1];
>   	struct i915_vma *trampoline; /** trampoline used for chaining */
>   
> +	/** used for excl fence in dma_resv objects when > 1 BB submitted */
> +	struct dma_fence *composite_fence;
> +
>   	/** actual size of execobj[] as we may extend it for the cmdparser */
>   	unsigned int buffer_count;
>   
> +	/* number of batches in execbuf IOCTL */
> +	unsigned int num_batches;
> +
>   	/** list of vma not yet bound during reservation phase */
>   	struct list_head unbound;
>   
> @@ -283,7 +291,8 @@ struct i915_execbuffer {
>   
>   	u64 invalid_flags; /** Set of execobj.flags that are invalid */
>   
> -	u64 batch_len; /** Length of batch within object */
> +	/** Length of batch within object */
> +	u64 batch_len[MAX_ENGINE_INSTANCE + 1];
>   	u32 batch_start_offset; /** Location within object of batch */
>   	u32 batch_flags; /** Flags composed for emit_bb_start() */
>   	struct intel_gt_buffer_pool_node *batch_pool; /** pool node for batch buffer */
> @@ -301,14 +310,13 @@ struct i915_execbuffer {
>   };
>   
>   static int eb_parse(struct i915_execbuffer *eb);
> -static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb,
> -					  bool throttle);
> +static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle);
>   static void eb_unpin_engine(struct i915_execbuffer *eb);
>   
>   static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb)
>   {
> -	return intel_engine_requires_cmd_parser(eb->engine) ||
> -		(intel_engine_using_cmd_parser(eb->engine) &&
> +	return intel_engine_requires_cmd_parser(eb->context->engine) ||
> +		(intel_engine_using_cmd_parser(eb->context->engine) &&
>   		 eb->args->batch_len);
>   }
>   
> @@ -546,11 +554,21 @@ eb_validate_vma(struct i915_execbuffer *eb,
>   	return 0;
>   }
>   
> -static void
> +static inline bool
> +is_batch_buffer(struct i915_execbuffer *eb, unsigned int buffer_idx)
> +{
> +	return eb->args->flags & I915_EXEC_BATCH_FIRST ?
> +		buffer_idx < eb->num_batches :
> +		buffer_idx >= eb->args->buffer_count - eb->num_batches;
> +}
> +
> +static int
>   eb_add_vma(struct i915_execbuffer *eb,
> -	   unsigned int i, unsigned batch_idx,
> +	   unsigned int *current_batch,
> +	   unsigned int i,
>   	   struct i915_vma *vma)
>   {
> +	struct drm_i915_private *i915 = eb->i915;
>   	struct drm_i915_gem_exec_object2 *entry = &eb->exec[i];
>   	struct eb_vma *ev = &eb->vma[i];
>   
> @@ -577,15 +595,43 @@ eb_add_vma(struct i915_execbuffer *eb,
>   	 * Note that actual hangs have only been observed on gen7, but for
>   	 * paranoia do it everywhere.
>   	 */
> -	if (i == batch_idx) {
> +	if (is_batch_buffer(eb, i)) {
>   		if (entry->relocation_count &&
>   		    !(ev->flags & EXEC_OBJECT_PINNED))
>   			ev->flags |= __EXEC_OBJECT_NEEDS_BIAS;
>   		if (eb->reloc_cache.has_fence)
>   			ev->flags |= EXEC_OBJECT_NEEDS_FENCE;
>   
> -		eb->batch = ev;
> +		eb->batches[*current_batch] = ev;
> +
> +		if (unlikely(ev->flags & EXEC_OBJECT_WRITE)) {
> +			drm_dbg(&i915->drm,
> +				"Attempting to use self-modifying batch buffer\n");
> +			return -EINVAL;
> +		}
> +
> +		if (range_overflows_t(u64,
> +				      eb->batch_start_offset,
> +				      eb->args->batch_len,
> +				      ev->vma->size)) {
> +			drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
> +			return -EINVAL;
> +		}
> +
> +		if (eb->args->batch_len == 0)
> +			eb->batch_len[*current_batch] = ev->vma->size -
> +				eb->batch_start_offset;
> +		else
> +			eb->batch_len[*current_batch] = eb->args->batch_len;
> +		if (unlikely(eb->batch_len[*current_batch] == 0)) { /* impossible! */
> +			drm_dbg(&i915->drm, "Invalid batch length\n");
> +			return -EINVAL;
> +		}
> +
> +		++*current_batch;
>   	}
> +
> +	return 0;
>   }
>   
>   static inline int use_cpu_reloc(const struct reloc_cache *cache,
> @@ -729,14 +775,6 @@ static int eb_reserve(struct i915_execbuffer *eb)
>   	} while (1);
>   }
>   
> -static unsigned int eb_batch_index(const struct i915_execbuffer *eb)
> -{
> -	if (eb->args->flags & I915_EXEC_BATCH_FIRST)
> -		return 0;
> -	else
> -		return eb->buffer_count - 1;
> -}
> -
>   static int eb_select_context(struct i915_execbuffer *eb)
>   {
>   	struct i915_gem_context *ctx;
> @@ -857,9 +895,7 @@ static struct i915_vma *eb_lookup_vma(struct i915_execbuffer *eb, u32 handle)
>   
>   static int eb_lookup_vmas(struct i915_execbuffer *eb)
>   {
> -	struct drm_i915_private *i915 = eb->i915;
> -	unsigned int batch = eb_batch_index(eb);
> -	unsigned int i;
> +	unsigned int i, current_batch = 0;
>   	int err = 0;
>   
>   	INIT_LIST_HEAD(&eb->relocs);
> @@ -879,7 +915,9 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
>   			goto err;
>   		}
>   
> -		eb_add_vma(eb, i, batch, vma);
> +		err = eb_add_vma(eb, &current_batch, i, vma);
> +		if (err)
> +			return err;
>   
>   		if (i915_gem_object_is_userptr(vma->obj)) {
>   			err = i915_gem_object_userptr_submit_init(vma->obj);
> @@ -902,26 +940,6 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
>   		}
>   	}
>   
> -	if (unlikely(eb->batch->flags & EXEC_OBJECT_WRITE)) {
> -		drm_dbg(&i915->drm,
> -			"Attempting to use self-modifying batch buffer\n");
> -		return -EINVAL;
> -	}
> -
> -	if (range_overflows_t(u64,
> -			      eb->batch_start_offset, eb->batch_len,
> -			      eb->batch->vma->size)) {
> -		drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
> -		return -EINVAL;
> -	}
> -
> -	if (eb->batch_len == 0)
> -		eb->batch_len = eb->batch->vma->size - eb->batch_start_offset;
> -	if (unlikely(eb->batch_len == 0)) { /* impossible! */
> -		drm_dbg(&i915->drm, "Invalid batch length\n");
> -		return -EINVAL;
> -	}
> -
>   	return 0;
>   
>   err:
> @@ -1654,8 +1672,7 @@ static int eb_reinit_userptr(struct i915_execbuffer *eb)
>   	return 0;
>   }
>   
> -static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
> -					   struct i915_request *rq)
> +static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb)
>   {
>   	bool have_copy = false;
>   	struct eb_vma *ev;
> @@ -1671,21 +1688,6 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
>   	eb_release_vmas(eb, false);
>   	i915_gem_ww_ctx_fini(&eb->ww);
>   
> -	if (rq) {
> -		/* nonblocking is always false */
> -		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> -				      MAX_SCHEDULE_TIMEOUT) < 0) {
> -			i915_request_put(rq);
> -			rq = NULL;
> -
> -			err = -EINTR;
> -			goto err_relock;
> -		}
> -
> -		i915_request_put(rq);
> -		rq = NULL;
> -	}
> -
>   	/*
>   	 * We take 3 passes through the slowpatch.
>   	 *
> @@ -1712,28 +1714,21 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
>   	if (!err)
>   		err = eb_reinit_userptr(eb);
>   
> -err_relock:
>   	i915_gem_ww_ctx_init(&eb->ww, true);
>   	if (err)
>   		goto out;
>   
>   	/* reacquire the objects */
>   repeat_validate:
> -	rq = eb_pin_engine(eb, false);
> -	if (IS_ERR(rq)) {
> -		err = PTR_ERR(rq);
> -		rq = NULL;
> +	err = eb_pin_engine(eb, false);
> +	if (err)
>   		goto err;
> -	}
> -
> -	/* We didn't throttle, should be NULL */
> -	GEM_WARN_ON(rq);
>   
>   	err = eb_validate_vmas(eb);
>   	if (err)
>   		goto err;
>   
> -	GEM_BUG_ON(!eb->batch);
> +	GEM_BUG_ON(!eb->batches[0]);
>   
>   	list_for_each_entry(ev, &eb->relocs, reloc_link) {
>   		if (!have_copy) {
> @@ -1797,46 +1792,23 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
>   		}
>   	}
>   
> -	if (rq)
> -		i915_request_put(rq);
> -
>   	return err;
>   }
>   
>   static int eb_relocate_parse(struct i915_execbuffer *eb)
>   {
>   	int err;
> -	struct i915_request *rq = NULL;
>   	bool throttle = true;
>   
>   retry:
> -	rq = eb_pin_engine(eb, throttle);
> -	if (IS_ERR(rq)) {
> -		err = PTR_ERR(rq);
> -		rq = NULL;
> +	err = eb_pin_engine(eb, throttle);
> +	if (err) {
>   		if (err != -EDEADLK)
>   			return err;
>   
>   		goto err;
>   	}
>   
> -	if (rq) {
> -		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
> -
> -		/* Need to drop all locks now for throttling, take slowpath */
> -		err = i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE, 0);
> -		if (err == -ETIME) {
> -			if (nonblock) {
> -				err = -EWOULDBLOCK;
> -				i915_request_put(rq);
> -				goto err;
> -			}
> -			goto slow;
> -		}
> -		i915_request_put(rq);
> -		rq = NULL;
> -	}
> -
>   	/* only throttle once, even if we didn't need to throttle */
>   	throttle = false;
>   
> @@ -1876,7 +1848,7 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
>   	return err;
>   
>   slow:
> -	err = eb_relocate_parse_slow(eb, rq);
> +	err = eb_relocate_parse_slow(eb);
>   	if (err)
>   		/*
>   		 * If the user expects the execobject.offset and
> @@ -1890,11 +1862,40 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
>   	return err;
>   }
>   
> +/*
> + * Using two helper loops for the order of which requests / batches are created
> + * and added the to backend. Requests are created in order from the parent to
> + * the last child. Requests are added in the reverse order, from the last child
> + * to parent. This is done for locking reasons as the timeline lock is acquired
> + * during request creation and released when the request is added to the
> + * backend. To make lockdep happy (see intel_context_timeline_lock) this must be
> + * the ordering.
> + */
> +#define for_each_batch_create_order(_eb, _i) \
> +	for ((_i) = 0; (_i) < (_eb)->num_batches; ++(_i))
> +#define for_each_batch_add_order(_eb, _i) \
> +	BUILD_BUG_ON(!typecheck(int, _i)); \
> +	for ((_i) = (_eb)->num_batches - 1; (_i) >= 0; --(_i))
> +
> +static struct i915_request *
> +eb_find_first_request_added(struct i915_execbuffer *eb)
> +{
> +	int i;
> +
> +	for_each_batch_add_order(eb, i)
> +		if (eb->requests[i])
> +			return eb->requests[i];
> +
> +	GEM_BUG_ON("Request not found");
> +
> +	return NULL;
> +}
> +
>   static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   {
>   	const unsigned int count = eb->buffer_count;
>   	unsigned int i = count;
> -	int err = 0;
> +	int err = 0, j;
>   
>   	while (i--) {
>   		struct eb_vma *ev = &eb->vma[i];
> @@ -1907,11 +1908,17 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   		if (flags & EXEC_OBJECT_CAPTURE) {
>   			struct i915_capture_list *capture;
>   
> -			capture = kmalloc(sizeof(*capture), GFP_KERNEL);
> -			if (capture) {
> -				capture->next = eb->request->capture_list;
> -				capture->vma = vma;
> -				eb->request->capture_list = capture;
> +			for_each_batch_create_order(eb, j) {
> +				if (!eb->requests[j])
> +					break;
> +
> +				capture = kmalloc(sizeof(*capture), GFP_KERNEL);
> +				if (capture) {
> +					capture->next =
> +						eb->requests[j]->capture_list;
> +					capture->vma = vma;
> +					eb->requests[j]->capture_list = capture;
> +				}
>   			}
>   		}
>   
> @@ -1932,14 +1939,26 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   				flags &= ~EXEC_OBJECT_ASYNC;
>   		}
>   
> +		/* We only need to await on the first request */
>   		if (err == 0 && !(flags & EXEC_OBJECT_ASYNC)) {
>   			err = i915_request_await_object
> -				(eb->request, obj, flags & EXEC_OBJECT_WRITE);
> +				(eb_find_first_request_added(eb), obj,
> +				 flags & EXEC_OBJECT_WRITE);
>   		}
>   
> -		if (err == 0)
> -			err = i915_vma_move_to_active(vma, eb->request,
> -						      flags | __EXEC_OBJECT_NO_RESERVE);
> +		for_each_batch_add_order(eb, j) {
> +			if (err)
> +				break;
> +			if (!eb->requests[j])
> +				continue;
> +
> +			err = _i915_vma_move_to_active(vma, eb->requests[j],
> +						       j ? NULL :
> +						       eb->composite_fence ?
> +						       eb->composite_fence :
> +						       &eb->requests[j]->fence,
> +						       flags | __EXEC_OBJECT_NO_RESERVE);
> +		}
>   	}
>   
>   #ifdef CONFIG_MMU_NOTIFIER
> @@ -1970,11 +1989,16 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   		goto err_skip;
>   
>   	/* Unconditionally flush any chipset caches (for streaming writes). */
> -	intel_gt_chipset_flush(eb->engine->gt);
> +	intel_gt_chipset_flush(eb->gt);
>   	return 0;
>   
>   err_skip:
> -	i915_request_set_error_once(eb->request, err);
> +	for_each_batch_create_order(eb, j) {
> +		if (!eb->requests[j])
> +			break;
> +
> +		i915_request_set_error_once(eb->requests[j], err);
> +	}
>   	return err;
>   }
>   
> @@ -2069,14 +2093,17 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	int err;
>   
>   	if (!eb_use_cmdparser(eb)) {
> -		batch = eb_dispatch_secure(eb, eb->batch->vma);
> +		batch = eb_dispatch_secure(eb, eb->batches[0]->vma);
>   		if (IS_ERR(batch))
>   			return PTR_ERR(batch);
>   
>   		goto secure_batch;
>   	}
>   
> -	len = eb->batch_len;
> +	if (intel_context_is_parallel(eb->context))
> +		return -EINVAL;
> +
> +	len = eb->batch_len[0];
>   	if (!CMDPARSER_USES_GGTT(eb->i915)) {
>   		/*
>   		 * ppGTT backed shadow buffers must be mapped RO, to prevent
> @@ -2090,11 +2117,11 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	} else {
>   		len += I915_CMD_PARSER_TRAMPOLINE_SIZE;
>   	}
> -	if (unlikely(len < eb->batch_len)) /* last paranoid check of overflow */
> +	if (unlikely(len < eb->batch_len[0])) /* last paranoid check of overflow */
>   		return -EINVAL;
>   
>   	if (!pool) {
> -		pool = intel_gt_get_buffer_pool(eb->engine->gt, len,
> +		pool = intel_gt_get_buffer_pool(eb->gt, len,
>   						I915_MAP_WB);
>   		if (IS_ERR(pool))
>   			return PTR_ERR(pool);
> @@ -2119,7 +2146,7 @@ static int eb_parse(struct i915_execbuffer *eb)
>   		trampoline = shadow;
>   
>   		shadow = shadow_batch_pin(eb, pool->obj,
> -					  &eb->engine->gt->ggtt->vm,
> +					  &eb->gt->ggtt->vm,
>   					  PIN_GLOBAL);
>   		if (IS_ERR(shadow)) {
>   			err = PTR_ERR(shadow);
> @@ -2141,26 +2168,29 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	if (err)
>   		goto err_trampoline;
>   
> -	err = intel_engine_cmd_parser(eb->engine,
> -				      eb->batch->vma,
> +	err = intel_engine_cmd_parser(eb->context->engine,
> +				      eb->batches[0]->vma,
>   				      eb->batch_start_offset,
> -				      eb->batch_len,
> +				      eb->batch_len[0],
>   				      shadow, trampoline);
>   	if (err)
>   		goto err_unpin_batch;
>   
> -	eb->batch = &eb->vma[eb->buffer_count++];
> -	eb->batch->vma = i915_vma_get(shadow);
> -	eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
> +	eb->batches[0] = &eb->vma[eb->buffer_count++];
> +	eb->batches[0]->vma = i915_vma_get(shadow);
> +	eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
>   
>   	eb->trampoline = trampoline;
>   	eb->batch_start_offset = 0;
>   
>   secure_batch:
>   	if (batch) {
> -		eb->batch = &eb->vma[eb->buffer_count++];
> -		eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
> -		eb->batch->vma = i915_vma_get(batch);
> +		if (intel_context_is_parallel(eb->context))
> +			return -EINVAL;
> +
> +		eb->batches[0] = &eb->vma[eb->buffer_count++];
> +		eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
> +		eb->batches[0]->vma = i915_vma_get(batch);
>   	}
>   	return 0;
>   
> @@ -2176,19 +2206,18 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	return err;
>   }
>   
> -static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
> +static int eb_request_submit(struct i915_execbuffer *eb,
> +			     struct i915_request *rq,
> +			     struct i915_vma *batch,
> +			     u64 batch_len)
>   {
>   	int err;
>   
> -	if (intel_context_nopreempt(eb->context))
> -		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &eb->request->fence.flags);
> -
> -	err = eb_move_to_gpu(eb);
> -	if (err)
> -		return err;
> +	if (intel_context_nopreempt(rq->context))
> +		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags);
>   
>   	if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
> -		err = i915_reset_gen7_sol_offsets(eb->request);
> +		err = i915_reset_gen7_sol_offsets(rq);
>   		if (err)
>   			return err;
>   	}
> @@ -2199,26 +2228,26 @@ static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
>   	 * allows us to determine if the batch is still waiting on the GPU
>   	 * or actually running by checking the breadcrumb.
>   	 */
> -	if (eb->engine->emit_init_breadcrumb) {
> -		err = eb->engine->emit_init_breadcrumb(eb->request);
> +	if (rq->context->engine->emit_init_breadcrumb) {
> +		err = rq->context->engine->emit_init_breadcrumb(rq);
>   		if (err)
>   			return err;
>   	}
>   
> -	err = eb->engine->emit_bb_start(eb->request,
> -					batch->node.start +
> -					eb->batch_start_offset,
> -					eb->batch_len,
> -					eb->batch_flags);
> +	err = rq->context->engine->emit_bb_start(rq,
> +						 batch->node.start +
> +						 eb->batch_start_offset,
> +						 batch_len,
> +						 eb->batch_flags);
>   	if (err)
>   		return err;
>   
>   	if (eb->trampoline) {
> +		GEM_BUG_ON(intel_context_is_parallel(rq->context));
>   		GEM_BUG_ON(eb->batch_start_offset);
> -		err = eb->engine->emit_bb_start(eb->request,
> -						eb->trampoline->node.start +
> -						eb->batch_len,
> -						0, 0);
> +		err = rq->context->engine->emit_bb_start(rq,
> +							 eb->trampoline->node.start +
> +							 batch_len, 0, 0);
>   		if (err)
>   			return err;
>   	}
> @@ -2226,6 +2255,27 @@ static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
>   	return 0;
>   }
>   
> +static int eb_submit(struct i915_execbuffer *eb)
> +{
> +	unsigned int i;
> +	int err;
> +
> +	err = eb_move_to_gpu(eb);
> +
> +	for_each_batch_create_order(eb, i) {
> +		if (!eb->requests[i])
> +			break;
> +
> +		trace_i915_request_queue(eb->requests[i], eb->batch_flags);
> +		if (!err)
> +			err = eb_request_submit(eb, eb->requests[i],
> +						eb->batches[i]->vma,
> +						eb->batch_len[i]);
> +	}
> +
> +	return err;
> +}
> +
>   static int num_vcs_engines(const struct drm_i915_private *i915)
>   {
>   	return hweight_long(VDBOX_MASK(&i915->gt));
> @@ -2291,26 +2341,11 @@ static struct i915_request *eb_throttle(struct i915_execbuffer *eb, struct intel
>   	return i915_request_get(rq);
>   }
>   
> -static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
> +static int eb_pin_timeline(struct i915_execbuffer *eb, struct intel_context *ce,
> +			   bool throttle)
>   {
> -	struct intel_context *ce = eb->context;
>   	struct intel_timeline *tl;
>   	struct i915_request *rq = NULL;
> -	int err;
> -
> -	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
> -
> -	if (unlikely(intel_context_is_banned(ce)))
> -		return ERR_PTR(-EIO);
> -
> -	/*
> -	 * Pinning the contexts may generate requests in order to acquire
> -	 * GGTT space, so do this first before we reserve a seqno for
> -	 * ourselves.
> -	 */
> -	err = intel_context_pin_ww(ce, &eb->ww);
> -	if (err)
> -		return ERR_PTR(err);
>   
>   	/*
>   	 * Take a local wakeref for preparing to dispatch the execbuf as
> @@ -2321,33 +2356,108 @@ static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throt
>   	 * taken on the engine, and the parent device.
>   	 */
>   	tl = intel_context_timeline_lock(ce);
> -	if (IS_ERR(tl)) {
> -		intel_context_unpin(ce);
> -		return ERR_CAST(tl);
> -	}
> +	if (IS_ERR(tl))
> +		return PTR_ERR(tl);
>   
>   	intel_context_enter(ce);
>   	if (throttle)
>   		rq = eb_throttle(eb, ce);
>   	intel_context_timeline_unlock(tl);
>   
> +	if (rq) {
> +		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
> +		long timeout = nonblock ? 0 : MAX_SCHEDULE_TIMEOUT;
> +
> +		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> +				      timeout) < 0) {
> +			i915_request_put(rq);
> +
> +			tl = intel_context_timeline_lock(ce);
> +			intel_context_exit(ce);
> +			intel_context_timeline_unlock(tl);
> +
> +			if (nonblock)
> +				return -EWOULDBLOCK;
> +			else
> +				return -EINTR;
> +		}
> +		i915_request_put(rq);
> +	}
> +
> +	return 0;
> +}
> +
> +static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
> +{
> +	struct intel_context *ce = eb->context, *child;
> +	int err;
> +	int i = 0, j = 0;
> +
> +	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
> +
> +	if (unlikely(intel_context_is_banned(ce)))
> +		return -EIO;
> +
> +	/*
> +	 * Pinning the contexts may generate requests in order to acquire
> +	 * GGTT space, so do this first before we reserve a seqno for
> +	 * ourselves.
> +	 */
> +	err = intel_context_pin_ww(ce, &eb->ww);
> +	if (err)
> +		return err;
> +	for_each_child(ce, child) {
> +		err = intel_context_pin_ww(child, &eb->ww);
> +		GEM_BUG_ON(err);	/* perma-pinned should incr a counter */
> +	}
> +
> +	for_each_child(ce, child) {
> +		err = eb_pin_timeline(eb, child, throttle);
> +		if (err)
> +			goto unwind;
> +		++i;
> +	}
> +	err = eb_pin_timeline(eb, ce, throttle);
> +	if (err)
> +		goto unwind;
> +
>   	eb->args->flags |= __EXEC_ENGINE_PINNED;
> -	return rq;
> +	return 0;
> +
> +unwind:
> +	for_each_child(ce, child) {
> +		if (j++ < i) {
> +			mutex_lock(&child->timeline->mutex);
> +			intel_context_exit(child);
> +			mutex_unlock(&child->timeline->mutex);
> +		}
> +	}
> +	for_each_child(ce, child)
> +		intel_context_unpin(child);
> +	intel_context_unpin(ce);
> +	return err;
>   }
>   
>   static void eb_unpin_engine(struct i915_execbuffer *eb)
>   {
> -	struct intel_context *ce = eb->context;
> -	struct intel_timeline *tl = ce->timeline;
> +	struct intel_context *ce = eb->context, *child;
>   
>   	if (!(eb->args->flags & __EXEC_ENGINE_PINNED))
>   		return;
>   
>   	eb->args->flags &= ~__EXEC_ENGINE_PINNED;
>   
> -	mutex_lock(&tl->mutex);
> +	for_each_child(ce, child) {
> +		mutex_lock(&child->timeline->mutex);
> +		intel_context_exit(child);
> +		mutex_unlock(&child->timeline->mutex);
> +
> +		intel_context_unpin(child);
> +	}
> +
> +	mutex_lock(&ce->timeline->mutex);
>   	intel_context_exit(ce);
> -	mutex_unlock(&tl->mutex);
> +	mutex_unlock(&ce->timeline->mutex);
>   
>   	intel_context_unpin(ce);
>   }
> @@ -2398,7 +2508,7 @@ eb_select_legacy_ring(struct i915_execbuffer *eb)
>   static int
>   eb_select_engine(struct i915_execbuffer *eb)
>   {
> -	struct intel_context *ce;
> +	struct intel_context *ce, *child;
>   	unsigned int idx;
>   	int err;
>   
> @@ -2411,6 +2521,20 @@ eb_select_engine(struct i915_execbuffer *eb)
>   	if (IS_ERR(ce))
>   		return PTR_ERR(ce);
>   
> +	if (intel_context_is_parallel(ce)) {
> +		if (eb->buffer_count < ce->parallel.number_children + 1) {
> +			intel_context_put(ce);
> +			return -EINVAL;
> +		}
> +		if (eb->batch_start_offset || eb->args->batch_len) {
> +			intel_context_put(ce);
> +			return -EINVAL;
> +		}
> +	}
> +	eb->num_batches = ce->parallel.number_children + 1;
> +
> +	for_each_child(ce, child)
> +		intel_context_get(child);
>   	intel_gt_pm_get(ce->engine->gt);
>   
>   	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
> @@ -2418,6 +2542,13 @@ eb_select_engine(struct i915_execbuffer *eb)
>   		if (err)
>   			goto err;
>   	}
> +	for_each_child(ce, child) {
> +		if (!test_bit(CONTEXT_ALLOC_BIT, &child->flags)) {
> +			err = intel_context_alloc_state(child);
> +			if (err)
> +				goto err;
> +		}
> +	}
>   
>   	/*
>   	 * ABI: Before userspace accesses the GPU (e.g. execbuffer), report
> @@ -2428,7 +2559,7 @@ eb_select_engine(struct i915_execbuffer *eb)
>   		goto err;
>   
>   	eb->context = ce;
> -	eb->engine = ce->engine;
> +	eb->gt = ce->engine->gt;
>   
>   	/*
>   	 * Make sure engine pool stays alive even if we call intel_context_put
> @@ -2439,6 +2570,8 @@ eb_select_engine(struct i915_execbuffer *eb)
>   
>   err:
>   	intel_gt_pm_put(ce->engine->gt);
> +	for_each_child(ce, child)
> +		intel_context_put(child);
>   	intel_context_put(ce);
>   	return err;
>   }
> @@ -2446,7 +2579,11 @@ eb_select_engine(struct i915_execbuffer *eb)
>   static void
>   eb_put_engine(struct i915_execbuffer *eb)
>   {
> -	intel_gt_pm_put(eb->engine->gt);
> +	struct intel_context *child;
> +
> +	intel_gt_pm_put(eb->gt);
> +	for_each_child(eb->context, child)
> +		intel_context_put(child);
>   	intel_context_put(eb->context);
>   }
>   
> @@ -2669,7 +2806,8 @@ static void put_fence_array(struct eb_fence *fences, int num_fences)
>   }
>   
>   static int
> -await_fence_array(struct i915_execbuffer *eb)
> +await_fence_array(struct i915_execbuffer *eb,
> +		  struct i915_request *rq)
>   {
>   	unsigned int n;
>   	int err;
> @@ -2683,8 +2821,7 @@ await_fence_array(struct i915_execbuffer *eb)
>   		if (!eb->fences[n].dma_fence)
>   			continue;
>   
> -		err = i915_request_await_dma_fence(eb->request,
> -						   eb->fences[n].dma_fence);
> +		err = i915_request_await_dma_fence(rq, eb->fences[n].dma_fence);
>   		if (err < 0)
>   			return err;
>   	}
> @@ -2692,9 +2829,9 @@ await_fence_array(struct i915_execbuffer *eb)
>   	return 0;
>   }
>   
> -static void signal_fence_array(const struct i915_execbuffer *eb)
> +static void signal_fence_array(const struct i915_execbuffer *eb,
> +			       struct dma_fence * const fence)
>   {
> -	struct dma_fence * const fence = &eb->request->fence;
>   	unsigned int n;
>   
>   	for (n = 0; n < eb->num_fences; n++) {
> @@ -2742,9 +2879,9 @@ static void retire_requests(struct intel_timeline *tl, struct i915_request *end)
>   			break;
>   }
>   
> -static int eb_request_add(struct i915_execbuffer *eb, int err)
> +static int eb_request_add(struct i915_execbuffer *eb, struct i915_request *rq,
> +			  int err, bool last_parallel)
>   {
> -	struct i915_request *rq = eb->request;
>   	struct intel_timeline * const tl = i915_request_timeline(rq);
>   	struct i915_sched_attr attr = {};
>   	struct i915_request *prev;
> @@ -2766,6 +2903,17 @@ static int eb_request_add(struct i915_execbuffer *eb, int err)
>   		err = -ENOENT; /* override any transient errors */
>   	}
>   
> +	if (intel_context_is_parallel(eb->context)) {
> +		if (err) {
> +			__i915_request_skip(rq);
> +			set_bit(I915_FENCE_FLAG_SKIP_PARALLEL,
> +				&rq->fence.flags);
> +		}
> +		if (last_parallel)
> +			set_bit(I915_FENCE_FLAG_SUBMIT_PARALLEL,
> +				&rq->fence.flags);
> +	}
> +
>   	__i915_request_queue(rq, &attr);
>   
>   	/* Try to clean up the client's timeline after submitting the request */
> @@ -2777,6 +2925,25 @@ static int eb_request_add(struct i915_execbuffer *eb, int err)
>   	return err;
>   }
>   
> +static int eb_requests_add(struct i915_execbuffer *eb, int err)
> +{
> +	int i;
> +
> +	/*
> +	 * We iterate in reverse order of creation to release timeline mutexes in
> +	 * same order.
> +	 */
> +	for_each_batch_add_order(eb, i) {
> +		struct i915_request *rq = eb->requests[i];
> +
> +		if (!rq)
> +			continue;
> +		err |= eb_request_add(eb, rq, err, i == 0);
> +	}
> +
> +	return err;
> +}
> +
>   static const i915_user_extension_fn execbuf_extensions[] = {
>   	[DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES] = parse_timeline_fences,
>   };
> @@ -2803,6 +2970,182 @@ parse_execbuf2_extensions(struct drm_i915_gem_execbuffer2 *args,
>   				    eb);
>   }
>   
> +static void eb_requests_get(struct i915_execbuffer *eb)
> +{
> +	unsigned int i;
> +
> +	for_each_batch_create_order(eb, i) {
> +		if (!eb->requests[i])
> +			break;
> +
> +		i915_request_get(eb->requests[i]);
> +	}
> +}
> +
> +static void eb_requests_put(struct i915_execbuffer *eb)
> +{
> +	unsigned int i;
> +
> +	for_each_batch_create_order(eb, i) {
> +		if (!eb->requests[i])
> +			break;
> +
> +		i915_request_put(eb->requests[i]);
> +	}
> +}
> +
> +static struct sync_file *
> +eb_composite_fence_create(struct i915_execbuffer *eb, int out_fence_fd)
> +{
> +	struct sync_file *out_fence = NULL;
> +	struct dma_fence_array *fence_array;
> +	struct dma_fence **fences;
> +	unsigned int i;
> +
> +	GEM_BUG_ON(!intel_context_is_parent(eb->context));
> +
> +	fences = kmalloc_array(eb->num_batches, sizeof(*fences), GFP_KERNEL);
> +	if (!fences)
> +		return ERR_PTR(-ENOMEM);
> +
> +	for_each_batch_create_order(eb, i)
> +		fences[i] = &eb->requests[i]->fence;
> +
> +	fence_array = dma_fence_array_create(eb->num_batches,
> +					     fences,
> +					     eb->context->parallel.fence_context,
> +					     eb->context->parallel.seqno,
> +					     false);
> +	if (!fence_array) {
> +		kfree(fences);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	/* Move ownership to the dma_fence_array created above */
> +	for_each_batch_create_order(eb, i)
> +		dma_fence_get(fences[i]);
> +
> +	if (out_fence_fd != -1) {
> +		out_fence = sync_file_create(&fence_array->base);
> +		/* sync_file now owns fence_arry, drop creation ref */
> +		dma_fence_put(&fence_array->base);
> +		if (!out_fence)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	eb->composite_fence = &fence_array->base;
> +
> +	return out_fence;
> +}
> +
> +static struct sync_file *
> +eb_fences_add(struct i915_execbuffer *eb, struct i915_request *rq,
> +	      struct dma_fence *in_fence, int out_fence_fd)
> +{
> +	struct sync_file *out_fence = NULL;
> +	int err;
> +
> +	if (unlikely(eb->gem_context->syncobj)) {
> +		struct dma_fence *fence;
> +
> +		fence = drm_syncobj_fence_get(eb->gem_context->syncobj);
> +		err = i915_request_await_dma_fence(rq, fence);
> +		dma_fence_put(fence);
> +		if (err)
> +			return ERR_PTR(err);
> +	}
> +
> +	if (in_fence) {
> +		if (eb->args->flags & I915_EXEC_FENCE_SUBMIT)
> +			err = i915_request_await_execution(rq, in_fence);
> +		else
> +			err = i915_request_await_dma_fence(rq, in_fence);
> +		if (err < 0)
> +			return ERR_PTR(err);
> +	}
> +
> +	if (eb->fences) {
> +		err = await_fence_array(eb, rq);
> +		if (err)
> +			return ERR_PTR(err);
> +	}
> +
> +	if (intel_context_is_parallel(eb->context)) {
> +		out_fence = eb_composite_fence_create(eb, out_fence_fd);
> +		if (IS_ERR(out_fence))
> +			return ERR_PTR(-ENOMEM);
> +	} else if (out_fence_fd != -1) {
> +		out_fence = sync_file_create(&rq->fence);
> +		if (!out_fence)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	return out_fence;
> +}
> +
> +static struct intel_context *
> +eb_find_context(struct i915_execbuffer *eb, unsigned int context_number)
> +{
> +	struct intel_context *child;
> +
> +	if (likely(context_number == 0))
> +		return eb->context;
> +
> +	for_each_child(eb->context, child)
> +		if (!--context_number)
> +			return child;
> +
> +	GEM_BUG_ON("Context not found");
> +
> +	return NULL;
> +}
> +
> +static struct sync_file *
> +eb_requests_create(struct i915_execbuffer *eb, struct dma_fence *in_fence,
> +		   int out_fence_fd)
> +{
> +	struct sync_file *out_fence = NULL;
> +	unsigned int i;
> +
> +	for_each_batch_create_order(eb, i) {
> +		/* Allocate a request for this batch buffer nice and early. */
> +		eb->requests[i] = i915_request_create(eb_find_context(eb, i));
> +		if (IS_ERR(eb->requests[i])) {
> +			out_fence = ERR_PTR(PTR_ERR(eb->requests[i]));
> +			eb->requests[i] = NULL;
> +			return out_fence;
> +		}
> +
> +		/*
> +		 * Only the first request added (committed to backend) has to
> +		 * take the in fences into account as all subsequent requests
> +		 * will have fences inserted inbetween them.
> +		 */
> +		if (i + 1 == eb->num_batches) {
> +			out_fence = eb_fences_add(eb, eb->requests[i],
> +						  in_fence, out_fence_fd);
> +			if (IS_ERR(out_fence))
> +				return out_fence;
> +		}
> +
> +		/*
> +		 * Whilst this request exists, batch_obj will be on the
> +		 * active_list, and so will hold the active reference. Only when
> +		 * this request is retired will the batch_obj be moved onto
> +		 * the inactive_list and lose its active reference. Hence we do
> +		 * not need to explicitly hold another reference here.
> +		 */
> +		eb->requests[i]->batch = eb->batches[i]->vma;
> +		if (eb->batch_pool) {
> +			GEM_BUG_ON(intel_context_is_parallel(eb->context));
> +			intel_gt_buffer_pool_mark_active(eb->batch_pool,
> +							 eb->requests[i]);
> +		}
> +	}
> +
> +	return out_fence;
> +}
> +
>   static int
>   i915_gem_do_execbuffer(struct drm_device *dev,
>   		       struct drm_file *file,
> @@ -2813,7 +3156,6 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   	struct i915_execbuffer eb;
>   	struct dma_fence *in_fence = NULL;
>   	struct sync_file *out_fence = NULL;
> -	struct i915_vma *batch;
>   	int out_fence_fd = -1;
>   	int err;
>   
> @@ -2837,12 +3179,15 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   
>   	eb.buffer_count = args->buffer_count;
>   	eb.batch_start_offset = args->batch_start_offset;
> -	eb.batch_len = args->batch_len;
>   	eb.trampoline = NULL;
>   
>   	eb.fences = NULL;
>   	eb.num_fences = 0;
>   
> +	memset(eb.requests, 0, sizeof(struct i915_request *) *
> +	       ARRAY_SIZE(eb.requests));
> +	eb.composite_fence = NULL;
> +
>   	eb.batch_flags = 0;
>   	if (args->flags & I915_EXEC_SECURE) {
>   		if (GRAPHICS_VER(i915) >= 11)
> @@ -2926,70 +3271,25 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   
>   	ww_acquire_done(&eb.ww.ctx);
>   
> -	batch = eb.batch->vma;
> -
> -	/* Allocate a request for this batch buffer nice and early. */
> -	eb.request = i915_request_create(eb.context);
> -	if (IS_ERR(eb.request)) {
> -		err = PTR_ERR(eb.request);
> -		goto err_vma;
> -	}
> -
> -	if (unlikely(eb.gem_context->syncobj)) {
> -		struct dma_fence *fence;
> -
> -		fence = drm_syncobj_fence_get(eb.gem_context->syncobj);
> -		err = i915_request_await_dma_fence(eb.request, fence);
> -		dma_fence_put(fence);
> -		if (err)
> -			goto err_ext;
> -	}
> -
> -	if (in_fence) {
> -		if (args->flags & I915_EXEC_FENCE_SUBMIT)
> -			err = i915_request_await_execution(eb.request,
> -							   in_fence);
> -		else
> -			err = i915_request_await_dma_fence(eb.request,
> -							   in_fence);
> -		if (err < 0)
> -			goto err_request;
> -	}
> -
> -	if (eb.fences) {
> -		err = await_fence_array(&eb);
> -		if (err)
> +	out_fence = eb_requests_create(&eb, in_fence, out_fence_fd);
> +	if (IS_ERR(out_fence)) {
> +		err = PTR_ERR(out_fence);
> +		if (eb.requests[0])
>   			goto err_request;
> +		else
> +			goto err_vma;
>   	}
>   
> -	if (out_fence_fd != -1) {
> -		out_fence = sync_file_create(&eb.request->fence);
> -		if (!out_fence) {
> -			err = -ENOMEM;
> -			goto err_request;
> -		}
> -	}
> -
> -	/*
> -	 * Whilst this request exists, batch_obj will be on the
> -	 * active_list, and so will hold the active reference. Only when this
> -	 * request is retired will the the batch_obj be moved onto the
> -	 * inactive_list and lose its active reference. Hence we do not need
> -	 * to explicitly hold another reference here.
> -	 */
> -	eb.request->batch = batch;
> -	if (eb.batch_pool)
> -		intel_gt_buffer_pool_mark_active(eb.batch_pool, eb.request);
> -
> -	trace_i915_request_queue(eb.request, eb.batch_flags);
> -	err = eb_submit(&eb, batch);
> +	err = eb_submit(&eb);
>   
>   err_request:
> -	i915_request_get(eb.request);
> -	err = eb_request_add(&eb, err);
> +	eb_requests_get(&eb);
> +	err = eb_requests_add(&eb, err);
>   
>   	if (eb.fences)
> -		signal_fence_array(&eb);
> +		signal_fence_array(&eb, eb.composite_fence ?
> +				   eb.composite_fence :
> +				   &eb.requests[0]->fence);
>   
>   	if (out_fence) {
>   		if (err == 0) {
> @@ -3004,10 +3304,15 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   
>   	if (unlikely(eb.gem_context->syncobj)) {
>   		drm_syncobj_replace_fence(eb.gem_context->syncobj,
> -					  &eb.request->fence);
> +					  eb.composite_fence ?
> +					  eb.composite_fence :
> +					  &eb.requests[0]->fence);
>   	}
>   
> -	i915_request_put(eb.request);
> +	if (!out_fence && eb.composite_fence)
> +		dma_fence_put(eb.composite_fence);
> +
> +	eb_requests_put(&eb);
>   
>   err_vma:
>   	eb_release_vmas(&eb, true);
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
> index edf12caaade3..246c37d72cd7 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context.h
> @@ -241,7 +241,13 @@ intel_context_timeline_lock(struct intel_context *ce)
>   	struct intel_timeline *tl = ce->timeline;
>   	int err;
>   
> -	err = mutex_lock_interruptible(&tl->mutex);
> +	if (intel_context_is_parent(ce))
> +		err = mutex_lock_interruptible_nested(&tl->mutex, 0);
> +	else if (intel_context_is_child(ce))
> +		err = mutex_lock_interruptible_nested(&tl->mutex,
> +						      ce->parallel.child_index + 1);
> +	else
> +		err = mutex_lock_interruptible(&tl->mutex);
>   	if (err)
>   		return ERR_PTR(err);
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 95a5b94b4ece..9e0177dc5484 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -248,6 +248,16 @@ struct intel_context {
>   		 * context
>   		 */
>   		struct i915_request *last_rq;
> +		/**
> +		 * @fence_context: fence context composite fence when doing
> +		 * parallel submission
> +		 */
> +		u64 fence_context;
> +		/**
> +		 * @seqno: seqno for composite fence when doing parallel
> +		 * submission
> +		 */
> +		u32 seqno;
>   		/** @number_children: number of children if parent */
>   		u8 number_children;
>   		/** @child_index: index into child_list if child */
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 50f0f4eba03b..361fab2cae99 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -3093,6 +3093,8 @@ guc_create_parallel(struct intel_engine_cs **engines,
>   		}
>   	}
>   
> +	parent->parallel.fence_context = dma_fence_context_alloc(1);
> +
>   	parent->engine->emit_bb_start =
>   		emit_bb_start_parent_no_preempt_mid_batch;
>   	parent->engine->emit_fini_breadcrumb =
> diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> index 8950785e55d6..24db8459376b 100644
> --- a/drivers/gpu/drm/i915/i915_request.h
> +++ b/drivers/gpu/drm/i915/i915_request.h
> @@ -147,6 +147,15 @@ enum {
>   	 * tail.
>   	 */
>   	I915_FENCE_FLAG_SUBMIT_PARALLEL,
> +
> +	/*
> +	 * I915_FENCE_FLAG_SKIP_PARALLEL - request with a context in a
> +	 * parent-child relationship (parallel submission, multi-lrc) that
> +	 * hit an error while generating requests in the execbuf IOCTL.
> +	 * Indicates this request should be skipped as another request in
> +	 * submission / relationship encoutered an error.
> +	 */
> +	I915_FENCE_FLAG_SKIP_PARALLEL,
>   };
>   
>   /**
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index 4b7fc4647e46..90546fa58fc1 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -1234,9 +1234,10 @@ int __i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq)
>   	return i915_active_add_request(&vma->active, rq);
>   }
>   
> -int i915_vma_move_to_active(struct i915_vma *vma,
> -			    struct i915_request *rq,
> -			    unsigned int flags)
> +int _i915_vma_move_to_active(struct i915_vma *vma,
> +			     struct i915_request *rq,
> +			     struct dma_fence *fence,
> +			     unsigned int flags)
>   {
>   	struct drm_i915_gem_object *obj = vma->obj;
>   	int err;
> @@ -1257,9 +1258,11 @@ int i915_vma_move_to_active(struct i915_vma *vma,
>   			intel_frontbuffer_put(front);
>   		}
>   
> -		dma_resv_add_excl_fence(vma->resv, &rq->fence);
> -		obj->write_domain = I915_GEM_DOMAIN_RENDER;
> -		obj->read_domains = 0;
> +		if (fence) {
> +			dma_resv_add_excl_fence(vma->resv, fence);
> +			obj->write_domain = I915_GEM_DOMAIN_RENDER;
> +			obj->read_domains = 0;
> +		}
>   	} else {
>   		if (!(flags & __EXEC_OBJECT_NO_RESERVE)) {
>   			err = dma_resv_reserve_shared(vma->resv, 1);
> @@ -1267,8 +1270,10 @@ int i915_vma_move_to_active(struct i915_vma *vma,
>   				return err;
>   		}
>   
> -		dma_resv_add_shared_fence(vma->resv, &rq->fence);
> -		obj->write_domain = 0;
> +		if (fence) {
> +			dma_resv_add_shared_fence(vma->resv, fence);
> +			obj->write_domain = 0;
> +		}
>   	}
>   
>   	if (flags & EXEC_OBJECT_NEEDS_FENCE && vma->fence)
> diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
> index ed69f66c7ab0..648dbe744c96 100644
> --- a/drivers/gpu/drm/i915/i915_vma.h
> +++ b/drivers/gpu/drm/i915/i915_vma.h
> @@ -57,9 +57,16 @@ static inline bool i915_vma_is_active(const struct i915_vma *vma)
>   
>   int __must_check __i915_vma_move_to_active(struct i915_vma *vma,
>   					   struct i915_request *rq);
> -int __must_check i915_vma_move_to_active(struct i915_vma *vma,
> -					 struct i915_request *rq,
> -					 unsigned int flags);
> +int __must_check _i915_vma_move_to_active(struct i915_vma *vma,
> +					  struct i915_request *rq,
> +					  struct dma_fence *fence,
> +					  unsigned int flags);
> +static inline int __must_check
> +i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq,
> +			unsigned int flags)
> +{
> +	return _i915_vma_move_to_active(vma, rq, &rq->fence, flags);
> +}
>   
>   #define __i915_vma_flags(v) ((unsigned long *)&(v)->flags.counter)
>   



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