ide: introduce ide_transfer_start_norecurse

For the case where the end_transfer_func is also the caller of
ide_transfer_start, the mutual recursion can lead to unlimited
stack usage.  Introduce a new version that can be used to change
tail recursion into a loop, and use it in trace_ide_atapi_cmd_reply_end.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180606190955.20845-8-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 9c4864ae54..2c62efc536 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -523,8 +523,8 @@ static void ide_clear_retry(IDEState *s)
 }
 
 /* prepare data transfer and tell what to do after */
-void ide_transfer_start(IDEState *s, uint8_t *buf, int size,
-                        EndTransferFunc *end_transfer_func)
+bool ide_transfer_start_norecurse(IDEState *s, uint8_t *buf, int size,
+                                  EndTransferFunc *end_transfer_func)
 {
     s->data_ptr = buf;
     s->data_end = buf + size;
@@ -534,10 +534,18 @@ void ide_transfer_start(IDEState *s, uint8_t *buf, int size,
     }
     if (!s->bus->dma->ops->pio_transfer) {
         s->end_transfer_func = end_transfer_func;
-        return;
+        return false;
     }
     s->bus->dma->ops->pio_transfer(s->bus->dma);
-    end_transfer_func(s);
+    return true;
+}
+
+void ide_transfer_start(IDEState *s, uint8_t *buf, int size,
+                        EndTransferFunc *end_transfer_func)
+{
+    if (ide_transfer_start_norecurse(s, buf, size, end_transfer_func)) {
+        end_transfer_func(s);
+    }
 }
 
 static void ide_cmd_done(IDEState *s)