From ccd98fe4996cd22094cde7b6a1f7c569f261b3e9 Mon Sep 17 00:00:00 2001 From: John Harrison Date: Fri, 29 May 2015 17:44:09 +0100 Subject: [PATCH] drm/i915: Add *_ring_begin() to request allocation Now that the *_ring_begin() functions no longer call the request allocation code, it is finally safe for the request allocation code to call *_ring_begin(). This is important to guarantee that the space reserved for the subsequent i915_add_request() call does actually get reserved. v2: Renamed functions according to review feedback (Tomas Elf). For: VIZ-5115 Signed-off-by: John Harrison Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem.c | 25 +++++++++++---------- drivers/gpu/drm/i915/intel_lrc.c | 15 +++++++++++++ drivers/gpu/drm/i915/intel_lrc.h | 1 + drivers/gpu/drm/i915/intel_ringbuffer.c | 29 ++++++++++++++----------- drivers/gpu/drm/i915/intel_ringbuffer.h | 1 + 5 files changed, 46 insertions(+), 25 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index e7a40f8712bc..0af4960d141c 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2679,19 +2679,20 @@ int i915_gem_request_alloc(struct intel_engine_cs *ring, * i915_add_request() call can't fail. Note that the reserve may need * to be redone if the request is not actually submitted straight * away, e.g. because a GPU scheduler has deferred it. - * - * Note further that this call merely notes the reserve request. A - * subsequent call to *_ring_begin() is required to actually ensure - * that the reservation is available. Without the begin, if the - * request creator immediately submitted the request without adding - * any commands to it then there might not actually be sufficient - * room for the submission commands. Unfortunately, the current - * *_ring_begin() implementations potentially call back here to - * i915_gem_request_alloc(). Thus calling _begin() here would lead to - * infinite recursion! Until that back call path is removed, it is - * necessary to do a manual _begin() outside. */ - intel_ring_reserved_space_reserve(req->ringbuf, MIN_SPACE_FOR_ADD_REQUEST); + if (i915.enable_execlists) + ret = intel_logical_ring_reserve_space(req); + else + ret = intel_ring_reserve_space(req); + if (ret) { + /* + * At this point, the request is fully allocated even if not + * fully prepared. Thus it can be cleaned up using the proper + * free code. + */ + i915_gem_request_cancel(req); + return ret; + } *req_out = ring->outstanding_lazy_request = req; return 0; diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index ad9db8a79d08..75c3b9dfec9e 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -834,6 +834,21 @@ static int intel_logical_ring_begin(struct drm_i915_gem_request *req, return 0; } +int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request) +{ + /* + * The first call merely notes the reserve request and is common for + * all back ends. The subsequent localised _begin() call actually + * ensures that the reservation is available. Without the begin, if + * the request creator immediately submitted the request without + * adding any commands to it then there might not actually be + * sufficient room for the submission commands. + */ + intel_ring_reserved_space_reserve(request->ringbuf, MIN_SPACE_FOR_ADD_REQUEST); + + return intel_logical_ring_begin(request, 0); +} + /** * execlists_submission() - submit a batchbuffer for execution, Execlists style * @dev: DRM device. diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h index 044c0e5c72e5..f59940ac1cfc 100644 --- a/drivers/gpu/drm/i915/intel_lrc.h +++ b/drivers/gpu/drm/i915/intel_lrc.h @@ -37,6 +37,7 @@ /* Logical Rings */ int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request); +int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request); void intel_logical_ring_stop(struct intel_engine_cs *ring); void intel_logical_ring_cleanup(struct intel_engine_cs *ring); int intel_logical_rings_init(struct drm_device *dev); diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index dfba3ee57382..a378360d0461 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -2202,24 +2202,27 @@ int intel_ring_alloc_request_extras(struct drm_i915_gem_request *request) return 0; } +int intel_ring_reserve_space(struct drm_i915_gem_request *request) +{ + /* + * The first call merely notes the reserve request and is common for + * all back ends. The subsequent localised _begin() call actually + * ensures that the reservation is available. Without the begin, if + * the request creator immediately submitted the request without + * adding any commands to it then there might not actually be + * sufficient room for the submission commands. + */ + intel_ring_reserved_space_reserve(request->ringbuf, MIN_SPACE_FOR_ADD_REQUEST); + + return intel_ring_begin(request, 0); +} + void intel_ring_reserved_space_reserve(struct intel_ringbuffer *ringbuf, int size) { - /* NB: Until request management is fully tidied up and the OLR is - * removed, there are too many ways for get false hits on this - * anti-recursion check! */ - /*WARN_ON(ringbuf->reserved_size);*/ + WARN_ON(ringbuf->reserved_size); WARN_ON(ringbuf->reserved_in_use); ringbuf->reserved_size = size; - - /* - * Really need to call _begin() here but that currently leads to - * recursion problems! This will be fixed later but for now just - * return and hope for the best. Note that there is only a real - * problem if the create of the request never actually calls _begin() - * but if they are not submitting any work then why did they create - * the request in the first place? - */ } void intel_ring_reserved_space_cancel(struct intel_ringbuffer *ringbuf) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 00a4ff7593ce..0f12020b54e9 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -484,6 +484,7 @@ intel_ring_get_request(struct intel_engine_cs *ring) * will always have sufficient room to do its stuff. The request creation * code calls this automatically. */ +int intel_ring_reserve_space(struct drm_i915_gem_request *request); void intel_ring_reserved_space_reserve(struct intel_ringbuffer *ringbuf, int size); /* Cancel the reservation, e.g. because the request is being discarded. */ void intel_ring_reserved_space_cancel(struct intel_ringbuffer *ringbuf); -- GitLab