[PATCH] serial COM: windows serial COM PollingFunc don't sleep

[Werner de Carne]

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1802
Signed-off-by: Werner de Carne <werner@carne.de>
---
 chardev/char-win.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/chardev/char-win.c b/chardev/char-win.c
index d4fb44c4dc..92a7016105 100644
--- a/chardev/char-win.c
+++ b/chardev/char-win.c
@@ -28,7 +28,7 @@
 #include "qapi/error.h"
 #include "chardev/char-win.h"
 
-static void win_chr_read(Chardev *chr, DWORD len)
+static int win_chr_read(Chardev *chr, DWORD len)
 {
     WinChardev *s = WIN_CHARDEV(chr);
     int max_size = qemu_chr_be_can_write(chr);
@@ -40,7 +40,7 @@ static void win_chr_read(Chardev *chr, DWORD len)
         len = max_size;
     }
     if (len == 0) {
-        return;
+        return 0;
     }
 
     ZeroMemory(&s->orecv, sizeof(s->orecv));
@@ -56,6 +56,8 @@ static void win_chr_read(Chardev *chr, DWORD len)
     if (size > 0) {
         qemu_chr_be_write(chr, buf, size);
     }
+    
+    return size > 0 ? 1 : 0;
 }
 
 static int win_chr_serial_poll(void *opaque)
@@ -67,8 +69,9 @@ static int win_chr_serial_poll(void *opaque)
 
     ClearCommError(s->file, &comerr, &status);
     if (status.cbInQue > 0) {
-        win_chr_read(chr, status.cbInQue);
-        return 1;
+        if (win_chr_read(chr, status.cbInQue)) {
+                       return 1;
+               }
     }
     return 0;
 }
@@ -147,8 +150,9 @@ int win_chr_pipe_poll(void *opaque)
 
     PeekNamedPipe(s->file, NULL, 0, NULL, &size, NULL);
     if (size > 0) {
-        win_chr_read(chr, size);
-        return 1;
+       if (win_chr_read(chr, size)) {
+                       return 1;
+               }
     }
     return 0;
 }
-- 
2.28.0.windows.1