[src/trunk]: src/sys Temporary fix for previous: avoid recursion through rnd_...

[tls <tls%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/15c0b07bab7e
branches:  trunk
changeset: 789611:15c0b07bab7e
user:      tls <tls%NetBSD.org@localhost>
date:      Mon Aug 26 23:41:24 2013 +0000

description:
Temporary fix for previous: avoid recursion through rnd_wakeup_readers()
when entropy first becomes available.

diffstat:

 sys/dev/rnd_private.h   |   5 +++--
 sys/kern/kern_rndq.c    |  31 +++++++++++++++++--------------
 sys/kern/kern_rndsink.c |   6 +++---
 3 files changed, 23 insertions(+), 19 deletions(-)

diffs (137 lines):

diff -r e7bd0bcdb135 -r 15c0b07bab7e sys/dev/rnd_private.h
--- a/sys/dev/rnd_private.h     Mon Aug 26 22:15:51 2013 +0000
+++ b/sys/dev/rnd_private.h     Mon Aug 26 23:41:24 2013 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: rnd_private.h,v 1.2 2013/08/25 21:12:56 tls Exp $     */
+/*      $NetBSD: rnd_private.h,v 1.3 2013/08/26 23:41:24 tls Exp $     */
 
 /*-
  * Copyright (c) 1997 The NetBSD Foundation, Inc.
@@ -55,6 +55,7 @@
                                      (short read ok) */
 
 uint32_t        rnd_extract_data(void *, uint32_t, uint32_t);
-void           rnd_process_events(void);       /* XXX should be static */
+int            rnd_process_events(void);       /* XXX should be static */
+void           rnd_wakeup_readers(void);       /* XXX should be static */
 
 #endif
diff -r e7bd0bcdb135 -r 15c0b07bab7e sys/kern/kern_rndq.c
--- a/sys/kern/kern_rndq.c      Mon Aug 26 22:15:51 2013 +0000
+++ b/sys/kern/kern_rndq.c      Mon Aug 26 23:41:24 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndq.c,v 1.15 2013/08/25 21:12:56 tls Exp $       */
+/*     $NetBSD: kern_rndq.c,v 1.16 2013/08/26 23:41:24 tls 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 1.15 2013/08/25 21:12:56 tls Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.16 2013/08/26 23:41:24 tls Exp $");
 
 #include <sys/param.h>
 #include <sys/ioctl.h>
@@ -141,7 +141,6 @@
 void *rnd_process, *rnd_wakeup;
 struct callout skew_callout;
 
-void         rnd_wakeup_readers(void);
 static inline u_int32_t rnd_estimate_entropy(krndsource_t *, u_int32_t);
 static inline u_int32_t rnd_counter(void);
 static        void     rnd_intr(void *);
@@ -169,7 +168,7 @@
                                        rnd_intr, NULL);
        rnd_wakeup = softint_establish(SOFTINT_CLOCK|SOFTINT_MPSAFE,
                                       rnd_wake, NULL);
-       rnd_process_events();
+       rnd_intr(NULL);
 }
 
 /*
@@ -816,8 +815,10 @@
  * by the add routines directly if the callout has never fired (that
  * is, if we are "cold" -- just booted).
  *
+ * Returns >0 if we got enough entropy to distribute some (wake sleepers)
+ * 0 elsewise.
  */
-void
+int
 rnd_process_events(void)
 {
        rnd_sample_t *sample = NULL;
@@ -931,19 +932,15 @@
                rnd_sample_free(sample);
        }
 
-       
-       /*
-        * Wake up any potential readers waiting.
-        */
-       if (wake) {
-               rnd_schedule_wakeup();
-       }
+       return wake;
 }
 
 static void
 rnd_intr(void *arg)
 {
-       rnd_process_events();
+       if (rnd_process_events()) {
+               rnd_schedule_wakeup();
+       }
 }
 
 static void
@@ -1031,13 +1028,19 @@
 u_int32_t
 rnd_extract_data(void *p, u_int32_t len, u_int32_t flags)
 {
+       int wake;
        uint32_t retval;
 
-       rnd_process_events();   /* XXX extra take/release rndpool_mtx */
+       wake = rnd_process_events(); /* XXX extra take/release rndpool_mtx */
 
        mutex_spin_enter(&rndpool_mtx);
        retval = rnd_extract_data_locked(p, len, flags);
        mutex_spin_exit(&rndpool_mtx);
+
+       if (wake) {
+               rnd_wakeup_readers();
+       }
+
        return retval;
 }
 
diff -r e7bd0bcdb135 -r 15c0b07bab7e sys/kern/kern_rndsink.c
--- a/sys/kern/kern_rndsink.c   Mon Aug 26 22:15:51 2013 +0000
+++ b/sys/kern/kern_rndsink.c   Mon Aug 26 23:41:24 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndsink.c,v 1.3 2013/08/25 21:12:56 tls Exp $     */
+/*     $NetBSD: kern_rndsink.c,v 1.4 2013/08/26 23:41:24 tls Exp $     */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rndsink.c,v 1.3 2013/08/25 21:12:56 tls Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndsink.c,v 1.4 2013/08/26 23:41:24 tls Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -131,7 +131,7 @@
 
        const uint32_t bits_needed = ((bytes + RND_ENTROPY_THRESHOLD) * NBBY);
 
-       rnd_process_events();   /* XXX extra take/release rndpool_mtx */
+       (void)rnd_process_events();  /* XXX extra take/release rndpool_mtx */
 
        mutex_spin_enter(&rndpool_mtx);
        if (bits_needed <= rndpool_get_entropy_count(&rnd_pool)) {