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Don't schedule a softint if we have nothing to do.

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Some systems seem to have gotten stuck in a softint processing loop
doing nothing and then trying to do it again.  Might fix gson's
frozen qemu/anita sparc autobuilds -- tested on macallan's real sparc
hardware and confirmed to fix at least some freeze at boot.
This commit is contained in:
riastradh 2016-02-17 19:44:40 +00:00
parent e6e528b81c
commit 446ef7b7a7
1 changed files with 10 additions and 10 deletions
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20
sys/kern/kern_rndq.c
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@ -1,4 +1,4 @@
/* $NetBSD: kern_rndq.c,v 1.80 2016/02/17 01:23:32 riastradh Exp $ */
/* $NetBSD: kern_rndq.c,v 1.81 2016/02/17 19:44:40 riastradh Exp $ */
/*-
* Copyright (c) 1997-2013 The NetBSD Foundation, Inc.
@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.80 2016/02/17 01:23:32 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.81 2016/02/17 19:44:40 riastradh Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@ -297,15 +297,15 @@ rnd_getmore(size_t byteswanted)
mutex_spin_exit(&rnd_global.lock);
/*
* Assume some callback is likely to have entered entropy
* synchronously. In that case, we may need to distribute
* entropy to waiters. Do that, if we can do it
* asynchronously. (Otherwise we may end up trying to
* distribute to the very rndsink that is trying to get more
* entropy in the first place, leading to lock recursion in
* that rndsink's callback.)
* Check whether we got entropy samples to process. In that
* case, we may need to distribute entropy to waiters. Do
* that, if we can do it asynchronously.
*
* - Conditionally because we don't want a softint loop.
* - Asynchronously because if we did it synchronously, we may
* end up with lock recursion on rndsinks_lock.
*/
if (__predict_true(rnd_process))
if (!SIMPLEQ_EMPTY(&rnd_samples.q) && rnd_process != NULL)
rnd_schedule_process();
}