X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fpoll-loop.c;h=de080b4c9e5d28c49fa4997fc92f5f1cf68f426a;hb=36ce148c6d2105dc2e485ec169bcc9998ffebf9d;hp=4e192f3ae0eaaacd863ce545247cf698de322850;hpb=959ec62e324d88e47930379d3f0d196119595de9;p=openvswitch

diff --git a/lib/poll-loop.c b/lib/poll-loop.c
index 4e192f3a..de080b4c 100644
--- a/lib/poll-loop.c
+++ b/lib/poll-loop.c
@@ -55,9 +55,6 @@ struct poll_waiter {
 /* All active poll waiters. */
 static struct list waiters = LIST_INITIALIZER(&waiters);
 
-/* Number of elements in the waiters list. */
-static size_t n_waiters;
-
 /* Max time to wait in next call to poll_block(), in milliseconds, or -1 to
  * wait forever. */
 static int timeout = -1;
@@ -65,6 +62,15 @@ static int timeout = -1;
 /* Location where waiter created. */
 static const char *timeout_where;
 
+/* Array of file descriptors from last run of poll_block(). */
+static struct pollfd *pollfds;
+
+/* Allocated size of pollfds. */
+static size_t max_pollfds;
+
+/* Current number of elements in pollfds. */
+static int n_pollfds;
+
 static struct poll_waiter *new_waiter(int fd, short int events,
                                       const char *where);
 
@@ -151,10 +157,10 @@ poll_immediate_wake(const char *where)
  * arguments have two possible interpretations:
  *
  *   - If 'pollfd' is nonnull then it should be the "struct pollfd" that caused
- *     the wakeup.  In this case, 'timeout' is ignored.
+ *     the wakeup.  'timeout' is ignored.
  *
- *   - If 'pollfd' is nonnull then 'timeout' is the number of milliseconds
- *     after which the poll loop woke up.
+ *   - If 'pollfd' is NULL then 'timeout' is the number of milliseconds after
+ *     which the poll loop woke up.
  */
 static void
 log_wakeup(const char *where, const struct pollfd *pollfd, int timeout)
@@ -213,17 +219,15 @@ log_wakeup(const char *where, const struct pollfd *pollfd, int timeout)
 void
 poll_block(void)
 {
-    static struct pollfd *pollfds;
-    static size_t max_pollfds;
-
     struct poll_waiter *pw, *next;
-    int n_pollfds;
+    int n_waiters;
     int retval;
 
     /* Register fatal signal events before actually doing any real work for
      * poll_block. */
     fatal_signal_wait();
 
+    n_waiters = list_size(&waiters);
     if (max_pollfds < n_waiters) {
         max_pollfds = n_waiters;
         pollfds = xrealloc(pollfds, max_pollfds * sizeof *pollfds);
@@ -275,9 +279,27 @@ poll_cancel(struct poll_waiter *pw)
     if (pw) {
         list_remove(&pw->node);
         free(pw);
-        n_waiters--;
     }
 }
+
+/* Checks whether the given file descriptor caused the poll loop to wake up
+ * in the previous iteration.  If it did, returns a bitmask of the events
+ * that caused the wakeup.  Otherwise returns 0;
+ */
+short int
+poll_fd_woke(int fd)
+{
+    int i;
+    short int events = 0;
+
+    for (i = 0; i < n_pollfds; i++) {
+        if (pollfds[i].fd == fd) {
+            events |= pollfds[i].revents;
+        }
+    }
+
+    return events;
+}
 
 /* Creates and returns a new poll_waiter for 'fd' and 'events'. */
 static struct poll_waiter *
@@ -289,6 +311,5 @@ new_waiter(int fd, short int events, const char *where)
     waiter->events = events;
     waiter->where = where;
     list_push_back(&waiters, &waiter->node);
-    n_waiters++;
     return waiter;
 }