[Xen-devel] [PATCH v2 2/3] xenfb: move xen_rmb to the correct location

[Wei Liu <wei.liu2@xxxxxxxxxx>]

It should be placed before first time producer and consumer are used.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Anthony Perard <anthony.perard@xxxxxxxxxx>

Backport candidate to our own tree.
---
 hw/display/xenfb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
index 9866dfd..7f4fad7 100644
--- a/hw/display/xenfb.c
+++ b/hw/display/xenfb.c
@@ -775,10 +775,10 @@ static void xenfb_handle_events(struct XenFB *xenfb)
 
     prod = page->out_prod;
     out_cons = page->out_cons;
+    xen_rmb();
     if (prod - out_cons > XENFB_OUT_RING_LEN) {
         return;
     }
-    xen_rmb();         /* ensure we see ring contents up to prod */
     for (cons = out_cons; cons != prod; cons++) {
        union xenfb_out_event *event = &XENFB_OUT_RING_REF(page, cons);
         uint8_t type = event->type;
-- 
2.1.4


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