Patchwork aio: fix aio_ctx_prepare with idle bottom halves

login
register
mail settings
Submitter Paolo Bonzini
Date Nov. 12, 2012, 12:30 p.m.
Message ID <1352723410-15705-1-git-send-email-pbonzini@redhat.com>
Download mbox | patch
Permalink /patch/198386/
State New
Headers show

Comments

Paolo Bonzini - Nov. 12, 2012, 12:30 p.m.
Commit ed2aec4867f0d5f5de496bb765347b5d0cfe113d changed the return
value of aio_ctx_prepare from false to true when only idle bottom
halves are available.  This broke PC old-style DMA, which uses them.
Fix this by making aio_ctx_prepare return true only when non-idle
bottom halves are scheduled to run.

Reported-by: malc <av1474@comtv.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
        Untested, I don't have an image that can do SB16.
        malc, can you test and perhaps apply?

 async.c | 6 ++----
 1 file modificato, 2 inserzioni(+), 4 rimozioni(-)
malc - Nov. 12, 2012, 4:03 p.m.
On Mon, 12 Nov 2012, Paolo Bonzini wrote:

> Commit ed2aec4867f0d5f5de496bb765347b5d0cfe113d changed the return
> value of aio_ctx_prepare from false to true when only idle bottom
> halves are available.  This broke PC old-style DMA, which uses them.
> Fix this by making aio_ctx_prepare return true only when non-idle
> bottom halves are scheduled to run.
> 

Applied, thanks.

[..snip..]

Patch

diff --git a/async.c b/async.c
index 04f9dcb..3f0e8f3 100644
--- a/async.c
+++ b/async.c
@@ -122,11 +122,9 @@  aio_ctx_prepare(GSource *source, gint    *timeout)
 {
     AioContext *ctx = (AioContext *) source;
     QEMUBH *bh;
-    bool scheduled = false;
 
     for (bh = ctx->first_bh; bh; bh = bh->next) {
         if (!bh->deleted && bh->scheduled) {
-            scheduled = true;
             if (bh->idle) {
                 /* idle bottom halves will be polled at least
                  * every 10ms */
@@ -135,12 +133,12 @@  aio_ctx_prepare(GSource *source, gint    *timeout)
                 /* non-idle bottom halves will be executed
                  * immediately */
                 *timeout = 0;
-                break;
+                return true;
             }
         }
     }
 
-    return scheduled;
+    return false;
 }
 
 static gboolean