Re: [PATCH v4 3/5] drm/i915: Create the locked version of the request create

On 3/8/2023 10:41 AM, Andi Shyti wrote:

Make version of the request creation that doesn't hold any lock.

Signed-off-by: Andi Shyti andi.shyti@linux.intel.com Cc: stable@vger.kernel.org

Reviewed-by: Nirmoy Das nirmoy.das@intel.com

---

drivers/gpu/drm/i915/i915_request.c | 43 +++++++++++++++++++---------- drivers/gpu/drm/i915/i915_request.h | 2 ++ 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 72aed544f8714..5ddb0e02b06b7 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -1028,18 +1028,11 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp) return ERR_PTR(ret); } -struct i915_request * -i915_request_create(struct intel_context *ce) +static struct i915_request * +__i915_request_create_locked(struct intel_context *ce) { struct i915_request *rq;

• struct intel_timeline *tl;
• if (intel_context_throttle(ce))

• return ERR_PTR(-EINTR);
  

• tl = intel_context_timeline_lock(ce);
• if (IS_ERR(tl))

• return ERR_CAST(tl);
  

• struct intel_timeline *tl = ce->timeline;

/* Move our oldest request to the slab-cache (if not in use!) */ rq = list_first_entry(&tl->requests, typeof(*rq), link); @@ -1049,16 +1042,38 @@ i915_request_create(struct intel_context *ce) intel_context_enter(ce); rq = __i915_request_create(ce, GFP_KERNEL); intel_context_exit(ce); /* active reference transferred to request */

• if (IS_ERR(rq))

• goto err_unlock;
  

/* Check that we do not interrupt ourselves with a new request */ rq->cookie = lockdep_pin_lock(&tl->mutex); return rq; +}

+struct i915_request * +i915_request_create_locked(struct intel_context *ce) +{

• intel_context_assert_timeline_is_locked(ce->timeline);
• if (intel_context_throttle(ce))

• return ERR_PTR(-EINTR);
  

• return __i915_request_create_locked(ce);

+}

+struct i915_request * +i915_request_create(struct intel_context *ce) +{

• struct i915_request *rq;
• struct intel_timeline *tl;
• tl = intel_context_timeline_lock(ce);
• if (IS_ERR(tl))

• return ERR_CAST(tl);
  

• rq = __i915_request_create_locked(ce);
• if (IS_ERR(rq))

• intel_context_timeline_unlock(tl);
  

-err_unlock:

• intel_context_timeline_unlock(tl); return rq; }

diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h index f5e1bb5e857aa..bb48bd4605c03 100644 --- a/drivers/gpu/drm/i915/i915_request.h +++ b/drivers/gpu/drm/i915/i915_request.h @@ -374,6 +374,8 @@ struct i915_request * __must_check __i915_request_create(struct intel_context *ce, gfp_t gfp); struct i915_request * __must_check i915_request_create(struct intel_context *ce); +struct i915_request * __must_check +i915_request_create_locked(struct intel_context *ce); void __i915_request_skip(struct i915_request *rq); bool i915_request_set_error_once(struct i915_request *rq, int error);