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[PULL,for-2.6,1/1] xenfb: use the correct condition to avoid excessive looping

Message ID 1461150922-14509-1-git-send-email-sstabellini@kernel.org (mailing list archive)
State New, archived
Headers show

Commit Message

Stefano Stabellini April 20, 2016, 11:15 a.m. UTC 
From: Wei Liu <wei.liu2@citrix.com>

In commit ac0487e1 ("xenfb.c: avoid expensive loops when prod <=
out_cons"), ">=" was used. In fact, a full ring is a legit state.
Correct the test to use ">".

Reported-by: "Hao, Xudong" <xudong.hao@intel.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: "Hao, Xudong" <xudong.hao@intel.com>
Acked-by: Anthony Perard <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/display/xenfb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
index 40b096a..9866dfd 100644
--- a/hw/display/xenfb.c
+++ b/hw/display/xenfb.c
@@ -775,7 +775,7 @@  static void xenfb_handle_events(struct XenFB *xenfb)
 
     prod = page->out_prod;
     out_cons = page->out_cons;
-    if (prod - out_cons >= XENFB_OUT_RING_LEN) {
+    if (prod - out_cons > XENFB_OUT_RING_LEN) {
         return;
     }
     xen_rmb();		/* ensure we see ring contents up to prod */