Commit 1dacb395 authored Dec 08, 2014 by Amos Kong Committed by Herbert Xu Dec 22, 2014

hwrng: move some code out mutex_lock for avoiding underlying deadlock



In next patch, we use reference counting for each struct hwrng,
changing reference count also needs to take mutex_lock. Before
releasing the lock, if we try to stop a kthread that waits to
take the lock to reduce the referencing count, deadlock will
occur.

Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 9372b35e

drivers/char/hw_random/core.c

+3 −3

Original line number	Original line	Diff line number	Diff line
	@@ -470,11 +470,11 @@ void hwrng_unregister(struct hwrng *rng)
	}		}
	}		}
	if (list_empty(&rng_list)) {		if (list_empty(&rng_list)) {
			mutex_unlock(&rng_mutex);
	unregister_miscdev();		unregister_miscdev();
	if (hwrng_fill)		if (hwrng_fill)
	kthread_stop(hwrng_fill);		kthread_stop(hwrng_fill);
	}		} else

	mutex_unlock(&rng_mutex);		mutex_unlock(&rng_mutex);
	}		}
	EXPORT_SYMBOL_GPL(hwrng_unregister);		EXPORT_SYMBOL_GPL(hwrng_unregister);