[src/trunk]: src/sys/kern Make rnd_getmore acquire rndpool_mtx itself.

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

details:   https://anonhg.NetBSD.org/src/rev/e9bd4eae83c7
branches:  trunk
changeset: 807574:e9bd4eae83c7
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Tue Apr 14 13:08:22 2015 +0000

description:
Make rnd_getmore acquire rndpool_mtx itself.

diffstat:

 sys/kern/kern_rndq.c    |  45 ++++++++++++++++++++++++++-------------------
 sys/kern/kern_rndsink.c |   6 ++----
 2 files changed, 28 insertions(+), 23 deletions(-)

diffs (156 lines):

diff -r 7bfa28c492fd -r e9bd4eae83c7 sys/kern/kern_rndq.c
--- a/sys/kern/kern_rndq.c      Tue Apr 14 13:05:33 2015 +0000
+++ b/sys/kern/kern_rndq.c      Tue Apr 14 13:08:22 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndq.c,v 1.54 2015/04/14 13:05:33 riastradh Exp $ */
+/*     $NetBSD: kern_rndq.c,v 1.55 2015/04/14 13:08:22 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 1.54 2015/04/14 13:05:33 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.55 2015/04/14 13:08:22 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -273,8 +273,7 @@
 {
        krndsource_t *rs;
 
-       KASSERT(mutex_owned(&rndpool_mtx));
-
+       mutex_spin_enter(&rndpool_mtx);
        LIST_FOREACH(rs, &rnd_sources, list) {
                if (!ISSET(rs->flags, RND_FLAG_HASCB))
                        continue;
@@ -286,6 +285,7 @@
                rnd_printf_verbose("rnd: asking source %s for %zu bytes\n",
                    rs->name, byteswanted);
        }
+       mutex_spin_exit(&rndpool_mtx);
 }
 
 /*
@@ -1099,6 +1099,13 @@
 skip:          SIMPLEQ_INSERT_TAIL(&df_samples, sample, next);
        }
        rndpool_set_entropy_count(&rnd_pool, pool_entropy);
+       mutex_spin_exit(&rndpool_mtx);
+
+       /*
+        * If we filled the pool past the threshold, wake anyone
+        * waiting for entropy.  Otherwise, ask all the entropy sources
+        * for more.
+        */
        if (pool_entropy > RND_ENTROPY_THRESHOLD * 8) {
                wake++;
        } else {
@@ -1106,7 +1113,6 @@
                rnd_printf_verbose("rnd: empty, asking for %d bytes\n",
                    (int)(howmany((RND_POOLBITS - pool_entropy), NBBY)));
        }
-       mutex_spin_exit(&rndpool_mtx);
 
        /* Now we hold no locks: clean up. */
        while ((sample = SIMPLEQ_FIRST(&df_samples))) {
@@ -1201,13 +1207,14 @@
        }
 #endif
        entropy_count = rndpool_get_entropy_count(&rnd_pool);
+       retval = rndpool_extract_data(&rnd_pool, p, len, flags);
+       mutex_spin_exit(&rndpool_mtx);
+
        if (entropy_count < (RND_ENTROPY_THRESHOLD * 2 + len) * NBBY) {
                rnd_printf_verbose("rnd: empty, asking for %d bytes\n",
                    (int)(howmany((RND_POOLBITS - entropy_count), NBBY)));
                rnd_getmore(howmany((RND_POOLBITS - entropy_count), NBBY));
        }
-       retval = rndpool_extract_data(&rnd_pool, p, len, flags);
-       mutex_spin_exit(&rndpool_mtx);
 
        return retval;
 }
@@ -1223,11 +1230,9 @@
            RND_EXTRACT_GOOD);
 
        if (extracted < bytes) {
+               rnd_getmore(bytes - extracted);
                (void)rnd_extract_data((uint8_t *)buffer + extracted,
                    bytes - extracted, RND_EXTRACT_ANY);
-               mutex_spin_enter(&rndpool_mtx);
-               rnd_getmore(bytes - extracted);
-               mutex_spin_exit(&rndpool_mtx);
                return false;
        }
 
@@ -1248,11 +1253,10 @@
 bool
 rnd_tryextract(void *buffer, size_t bytes)
 {
-       bool ok;
+       uint32_t bits_needed, bytes_requested;
 
        KASSERT(bytes <= RNDSINK_MAX_BYTES);
-
-       const uint32_t bits_needed = ((bytes + RND_ENTROPY_THRESHOLD) * NBBY);
+       bits_needed = ((bytes + RND_ENTROPY_THRESHOLD) * NBBY);
 
        mutex_spin_enter(&rndpool_mtx);
        if (bits_needed <= rndpool_get_entropy_count(&rnd_pool)) {
@@ -1261,16 +1265,19 @@
                        RND_EXTRACT_GOOD);
 
                KASSERT(extracted == bytes);
-
-               ok = true;
+               bytes_requested = 0;
        } else {
-               ok = false;
-               rnd_getmore(howmany(bits_needed -
-                       rndpool_get_entropy_count(&rnd_pool), NBBY));
+               /* XXX Figure the threshold into this...  */
+               bytes_requested = howmany((bits_needed -
+                       rndpool_get_entropy_count(&rnd_pool)), NBBY);
+               KASSERT(0 < bytes_requested);
        }
        mutex_spin_exit(&rndpool_mtx);
 
-       return ok;
+       if (0 < bytes_requested)
+               rnd_getmore(bytes_requested);
+
+       return bytes_requested == 0;
 }
 
 void
diff -r 7bfa28c492fd -r e9bd4eae83c7 sys/kern/kern_rndsink.c
--- a/sys/kern/kern_rndsink.c   Tue Apr 14 13:05:33 2015 +0000
+++ b/sys/kern/kern_rndsink.c   Tue Apr 14 13:08:22 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndsink.c,v 1.13 2015/04/13 22:43:41 riastradh Exp $      */
+/*     $NetBSD: kern_rndsink.c,v 1.14 2015/04/14 13:08:22 riastradh Exp $      */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rndsink.c,v 1.13 2015/04/13 22:43:41 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndsink.c,v 1.14 2015/04/14 13:08:22 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -156,9 +156,7 @@
         * or something -- as soon as we get that much from the entropy
         * sources, distribute it.
         */
-       mutex_spin_enter(&rndpool_mtx);
        rnd_getmore(MAX(rndsink->rsink_bytes, 2 * sizeof(uint32_t)));
-       mutex_spin_exit(&rndpool_mtx);
 
        switch (rndsink->rsink_state) {
        case RNDSINK_IDLE: