accel/habanalabs: minimize encapsulation signal mutex lock time

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@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

diff --git a/drivers/accel/habanalabs/common/command_submission.c b/drivers/accel/habanalabs/common/command_submission.c
index af9d2e22c6e7e08990a3cd4794a5a799203ff1ce..977cd2710686d0c60540b7291da7cac5dc28f467 100644 (file)
--- 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;
 }