[Qemu-devel] [PATCH v2] main_loop: Make main_loop_wait() return void

[Peter Maydell <peter.maydell@linaro.org>]

In commit e330c118f2a5a the last usage of main_loop_wait() that cared
about the return value was changed to no longer use it. Drop the
now-useless return value and make the function return void.

We avoid the awkwardness of ifdeffery to handle the 'ret'
variable in main_loop_wait() only being wanted if CONFIG_SLIRP
by simply dropping all the ifdefs. There are stub implementations
of slirp_pollfds_poll() and slirp_pollfds_fill() already in
stubs/slirp.c which do nothing, as required.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
This will coincidentally satisfy Coverity, which currently complains
in CID 1372464 that we call main_loop_wait() in vl.c and ignore the
return value which may be reporting a poll() syscall failure.
Essentially we don't expect poll() to fail, except perhaps with
a transient EINTR -- if it ever did we'd spin retrying endlessly
I think.
---
 include/qemu/main-loop.h | 2 +-
 util/main-loop.c         | 8 ++------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index d7e24af..6b4b60b 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -79,7 +79,7 @@ int qemu_init_main_loop(Error **errp);
  *
  * @nonblocking: Whether the caller should block until an event occurs.
  */
-int main_loop_wait(int nonblocking);
+void main_loop_wait(int nonblocking);
 
 /**
  * qemu_get_aio_context: Return the main loop's AioContext
diff --git a/util/main-loop.c b/util/main-loop.c
index 19cad6b..0b25405 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -487,7 +487,7 @@ static int os_host_main_loop_wait(int64_t timeout)
 }
 #endif
 
-int main_loop_wait(int nonblocking)
+void main_loop_wait(int nonblocking)
 {
     int ret;
     uint32_t timeout = UINT32_MAX;
@@ -500,9 +500,7 @@ int main_loop_wait(int nonblocking)
     /* poll any events */
     g_array_set_size(gpollfds, 0); /* reset for new iteration */
     /* XXX: separate device handlers from system ones */
-#ifdef CONFIG_SLIRP
     slirp_pollfds_fill(gpollfds, &timeout);
-#endif
 
     if (timeout == UINT32_MAX) {
         timeout_ns = -1;
@@ -515,16 +513,14 @@ int main_loop_wait(int nonblocking)
                                           &main_loop_tlg));
 
     ret = os_host_main_loop_wait(timeout_ns);
-#ifdef CONFIG_SLIRP
     slirp_pollfds_poll(gpollfds, (ret < 0));
-#endif
 
     /* CPU thread can infinitely wait for event after
        missing the warp */
     qemu_start_warp_timer();
     qemu_clock_run_all_timers();
 
-    return ret;
+    return;
 }
 
 /* Functions to operate on the main QEMU AioContext.  */
-- 
2.7.4