From patchwork Mon Sep 24 09:10:56 2012
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Subject: [v9,
 1/4] aio: Fix qemu_aio_wait() to maintain correct walking_handlers
 count
Date: Sun, 23 Sep 2012 23:10:56 -0000
From: Bharata B Rao <bharata@linux.vnet.ibm.com>
X-Patchwork-Id: 186331
Message-Id: <20120924091056.GK18470@in.ibm.com>
To: qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>,
 Anand Avati <aavati@redhat.com>, Vijay Bellur <vbellur@redhat.com>,
 Stefan Hajnoczi <stefanha@gmail.com>,
 Harsh Bora <harsh@linux.vnet.ibm.com>, Amar Tumballi <amarts@redhat.com>, 
 "Richard W.M. Jones" <rjones@redhat.com>,
 Daniel Veillard <veillard@redhat.com>,
 Blue Swirl <blauwirbel@gmail.com>, Avi Kivity <avi@redhat.com>,
 Paolo Bonzini <pbonzini@redhat.com>

aio: Fix qemu_aio_wait() to maintain correct walking_handlers count

From: Paolo Bonzini <pbonzini@redhat.com>

Fix qemu_aio_wait() to ensure that registered aio handlers don't get
deleted when they are still active. This is ensured by maintaning the
right count of walking_handlers.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>

---
aio.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/aio.c b/aio.c
index 0a9eb10..99b8b72 100644
--- a/aio.c
+++ b/aio.c
@@ -119,7 +119,7 @@ bool qemu_aio_wait(void)
         return true;
     }
 
-    walking_handlers = 1;
+    walking_handlers++;
 
     FD_ZERO(&rdfds);
     FD_ZERO(&wrfds);
@@ -147,7 +147,7 @@ bool qemu_aio_wait(void)
         }
     }
 
-    walking_handlers = 0;
+    walking_handlers--;
 
     /* No AIO operations?  Get us out of here */
     if (!busy) {
@@ -159,7 +159,7 @@ bool qemu_aio_wait(void)
 
     /* if we have any readable fds, dispatch event */
     if (ret > 0) {
-        walking_handlers = 1;
+        walking_handlers++;
 
         /* we have to walk very carefully in case
          * qemu_aio_set_fd_handler is called while we're walking */
@@ -187,7 +187,7 @@ bool qemu_aio_wait(void)
             }
         }
 
-        walking_handlers = 0;
+        walking_handlers--;
     }
 
     return true;