[PATCH 09/10] accel/habanalabs: minimize encapsulation signal mutex lock time

[Oded Gabbay]

From: Koby Elbaz <kelbaz at habana.ai>

Sync Stream Encapsulated Signal Handlers can be managed from different
contexts, and as such they are protected via a spin_lock.
However, spin_lock was unnecessarily protecting a larger code section
than really needed, covering a sleepable code section as well.
Since spin_lock disables preemption, it could lead to sleeping in
atomic context.

Signed-off-by: Koby Elbaz <kelbaz at habana.ai>
Reviewed-by: Oded Gabbay <ogabbay at kernel.org>
Signed-off-by: Oded Gabbay <ogabbay at kernel.org>
---
 drivers/accel/habanalabs/common/command_submission.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/accel/habanalabs/common/command_submission.c b/drivers/accel/habanalabs/common/command_submission.c
index 977900866e8f..56bc115e1b83 100644
--- a/drivers/accel/habanalabs/common/command_submission.c
+++ b/drivers/accel/habanalabs/common/command_submission.c
@@ -2152,7 +2152,7 @@ static int cs_ioctl_unreserve_signals(struct hl_fpriv *hpriv, u32 handle_id)
 
 			hdev->asic_funcs->hw_queues_unlock(hdev);
 			rc = -EINVAL;
-			goto out;
+			goto out_unlock;
 		}
 
 		/*
@@ -2167,15 +2167,21 @@ static int cs_ioctl_unreserve_signals(struct hl_fpriv *hpriv, u32 handle_id)
 
 		/* Release the id and free allocated memory of the handle */
 		idr_remove(&mgr->handles, handle_id);
+
+		/* unlock before calling ctx_put, where we might sleep */
+		spin_unlock(&mgr->lock);
 		hl_ctx_put(encaps_sig_hdl->ctx);
 		kfree(encaps_sig_hdl);
+		goto out;
 	} else {
 		rc = -EINVAL;
 		dev_err(hdev->dev, "failed to unreserve signals, cannot find handler\n");
 	}
-out:
+
+out_unlock:
 	spin_unlock(&mgr->lock);
 
+out:
 	return rc;
 }
 
-- 
2.40.0