Changeset 18915 in vbox

Timestamp:

Apr 15, 2009 8:50:39 PM (16 years ago)

Author:

vboxsync

Message:

Support/FreeBSD: Do reference counting to prevent the driver from getting unloaded while it is used

File:

• trunk/src/VBox/HostDrivers/Support/freebsd/SUPDrv-freebsd.c (modified) (6 diffs)

trunk/src/VBox/HostDrivers/Support/freebsd/SUPDrv-freebsd.c

@@ -104 +104 @@
 /** The dev_clone event handler tag. */
 static eventhandler_tag     g_VBoxDrvFreeBSDEHTag;
+/** Reference counter */
+static volatile uint32_t    cUsers;
 
 /** The device extention. */
@@ -148 +150 @@
 {
     dprintf(("VBoxDrvFreeBSDLoad:\n"));
+
+    cUsers = 0;
 
     /*
@@ -190 +194 @@
     dprintf(("VBoxDrvFreeBSDUnload:\n"));
 
-    /** @todo verify that FreeBSD does reference counting. */
+    if (cUsers > 0)
+        return EBUSY;
 
     /*
@@ -307 +312 @@
         pSession->Gid = stuff; */
         if (ASMAtomicCmpXchgPtr(&pDev->si_drv1, pSession, (void *)0x42))
+        {
+            ASMAtomicIncU32(&cUsers);
             return 0;
+        }
 
         OSDBGPRINT(("VBoxDrvFreeBSDOpen: si_drv1=%p, expected 0x42!\n", pDev->si_drv1));
@@ -339 +347 @@
         if (!ASMAtomicCmpXchgPtr(&pDev->si_drv1, NULL, pSession))
             OSDBGPRINT(("VBoxDrvFreeBSDClose: si_drv1=%p expected %p!\n", pDev->si_drv1, pSession));
+        ASMAtomicDecU32(&cUsers);
+        /* Don't use destroy_dev here because it may sleep resulting in a hanging user process. */
+        destroy_dev_sched(pDev);
     }
     else
@@ -491 +502 @@
                 OSDBGPRINT(("VBoxDrvFreeBSDIOCtlSlow: copyout(%p,%p,%#x) -> %d; uCmd=%#lx!\n", pHdr, pvUser, cbOut, rc, ulCmd));
 
+            dprintf(("VBoxDrvFreeBSDIOCtlSlow: returns %d / %d ulCmd=%lx\n", 0, pHdr->rc, ulCmd));
+
             /* cleanup */
             RTMemTmpFree(pHdr);
         }
-        dprintf(("VBoxDrvFreeBSDIOCtlSlow: returns %d / %d ulCmd=%lx\n", 0, pHdr->rc, ulCmd));
     }
     else