documentation: Sharpen up the no-readers quick quiz

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html
index acdad96..85cf223 100644 (file)
--- a/Documentation/RCU/Design/Requirements/Requirements.html
+++ b/Documentation/RCU/Design/Requirements/Requirements.html
@@ -1002,18 +1002,21 @@ obligation to wait for these new readers.
 <tr><th>&nbsp;</th></tr>
 <tr><th align="left">Quick Quiz:</th></tr>
 <tr><td>
-       Suppose that synchronize_rcu() did wait until all readers had completed.
-       Would the updater be able to rely on this?
+       Suppose that synchronize_rcu() did wait until <i>all</i>
+       readers had completed instead of waiting only on
+       pre-existing readers.
+       For how long would the updater be able to rely on there
+       being no readers?
 </td></tr>
 <tr><th align="left">Answer:</th></tr>
 <tr><td bgcolor="#ffffff"><font color="ffffff">
-       No.
+       For no time at all.
        Even if <tt>synchronize_rcu()</tt> were to wait until
        all readers had completed, a new reader might start immediately after
        <tt>synchronize_rcu()</tt> completed.
        Therefore, the code following
-       <tt>synchronize_rcu()</tt> cannot rely on there being no readers
-       in any case.
+       <tt>synchronize_rcu()</tt> can <i>never</i> rely on there being
+       no readers.
 </font></td></tr>
 <tr><td>&nbsp;</td></tr>
 </table>