[Qemu-devel] [PATCH v2 4/5] iohandlers: Enable an iohandler only if the associated handler exists

[Amit Shah]

If an iohandler is asked to be enabled but the handler doesn't exist,
don't enable the handler.

This can be used to simplify the conditions in main_loop_wait().

Signed-off-by: Amit Shah <amit.s...@redhat.com>
---
 vl.c |   29 ++++++++++++++++++++---------
 1 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/vl.c b/vl.c
index b9c902a..4aa4158 100644
--- a/vl.c
+++ b/vl.c
@@ -1049,7 +1049,11 @@ int set_read_poll_fd_action(int fd, bool enable)
     if (!ioh) {
         return -1;
     }
-    ioh->read_poll_enabled = enable;
+
+    ioh->read_poll_enabled = false;
+    if (enable && ioh->fd_read_poll) {
+        ioh->read_poll_enabled = true;
+    }
 
     return 0;
 }
@@ -1066,7 +1070,11 @@ int set_read_fd_action(int fd, bool enable)
     if (!ioh) {
         return -1;
     }
-    ioh->read_enabled = enable;
+
+    ioh->read_enabled = false;
+    if (enable && ioh->fd_read) {
+        ioh->read_enabled = true;
+    }
 
     return 0;
 }
@@ -1083,7 +1091,11 @@ int set_write_fd_action(int fd, bool enable)
     if (!ioh) {
         return -1;
     }
-    ioh->write_enabled = enable;
+
+    ioh->write_enabled = false;
+    if (enable && ioh->fd_write) {
+        ioh->write_enabled = true;
+    }
 
     return 0;
 }
@@ -1421,14 +1433,13 @@ void main_loop_wait(int nonblocking)
     QLIST_FOREACH(ioh, &io_handlers, next) {
         if (ioh->deleted)
             continue;
-        if (ioh->fd_read && ioh->read_enabled &&
-            (!ioh->fd_read_poll ||
-             (!ioh->read_poll_enabled || ioh->fd_read_poll(ioh->opaque) != 
0))) {
+        if (ioh->read_enabled &&
+            (!ioh->read_poll_enabled || ioh->fd_read_poll(ioh->opaque) != 0)) {
             FD_SET(ioh->fd, &rfds);
             if (ioh->fd > nfds)
                 nfds = ioh->fd;
         }
-        if (ioh->fd_write && ioh->write_enabled) {
+        if (ioh->write_enabled) {
             FD_SET(ioh->fd, &wfds);
             if (ioh->fd > nfds)
                 nfds = ioh->fd;
@@ -1447,10 +1458,10 @@ void main_loop_wait(int nonblocking)
         IOHandlerRecord *pioh;
 
         QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
-            if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, &rfds)) {
+            if (!ioh->deleted && ioh->read_enabled && FD_ISSET(ioh->fd, 
&rfds)) {
                 ioh->fd_read(ioh->opaque);
             }
-            if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, &wfds)) {
+            if (!ioh->deleted && ioh->write_enabled && FD_ISSET(ioh->fd, 
&wfds)) {
                 ioh->fd_write(ioh->opaque);
             }
 
-- 
1.7.3.4