[PATCH 5.15 244/279] drm/i915/guc: Dont drop ce->guc_active.lock when unwinding context

Greg Kroah-Hartman
2021-11-24T14:02:45Z

From: Matthew Brost <matthew.brost@intel.com>

commit 88209a8ecb8b8752322908a3c3362a001bdc3a39 upstream.

Don't drop ce->guc_active.lock when unwinding a context after reset.
At one point we had to drop this because of a lock inversion but that is
no longer the case. It is much safer to hold the lock so let's do that.

Fixes: eb5e7da736f3 ("drm/i915/guc: Reset implementation for new GuC interface")
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-5-matthew.brost@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 4 ----
1 file changed, 4 deletions(-)

--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -814,8 +814,6 @@ __unwind_incomplete_requests(struct inte
continue;

list_del_init(&rq->sched.link);
- spin_unlock(&ce->guc_active.lock);
-
__i915_request_unsubmit(rq);

/* Push the request back into the queue for later resubmission. */
@@ -828,8 +826,6 @@ __unwind_incomplete_requests(struct inte

list_add_tail(&rq->sched.link, pl);
set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
-
- spin_lock(&ce->guc_active.lock);
}
spin_unlock(&ce->guc_active.lock);
spin_unlock_irqrestore(&sched_engine->lock, flags);