svn commit: r263961 - stable/10/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Mon Mar 31 02:30:55 2014
New Revision: 263961
URL: http://svnweb.freebsd.org/changeset/base/263961

Log:
  MFC r263704:
  Make /dev/devctl mpsafe.
  
  MFC r263753:
  Remove lockless check in devopen, while correct it does not make much sense.

Modified:
  stable/10/sys/kern/subr_bus.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/kern/subr_bus.c
==============================================================================
--- stable/10/sys/kern/subr_bus.c       Mon Mar 31 02:24:29 2014        
(r263960)
+++ stable/10/sys/kern/subr_bus.c       Mon Mar 31 02:30:55 2014        
(r263961)
@@ -358,15 +358,16 @@ device_sysctl_fini(device_t dev)
 /* Deprecated way to adjust queue length */
 static int sysctl_devctl_disable(SYSCTL_HANDLER_ARGS);
 /* XXX Need to support old-style tunable hw.bus.devctl_disable" */
-SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_disable, CTLTYPE_INT | CTLFLAG_RW, NULL,
-    0, sysctl_devctl_disable, "I", "devctl disable -- deprecated");
+SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_disable, CTLTYPE_INT | CTLFLAG_RW |
+    CTLFLAG_MPSAFE, NULL, 0, sysctl_devctl_disable, "I",
+    "devctl disable -- deprecated");
 
 #define DEVCTL_DEFAULT_QUEUE_LEN 1000
 static int sysctl_devctl_queue(SYSCTL_HANDLER_ARGS);
 static int devctl_queue_length = DEVCTL_DEFAULT_QUEUE_LEN;
 TUNABLE_INT("hw.bus.devctl_queue", &devctl_queue_length);
-SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_queue, CTLTYPE_INT | CTLFLAG_RW, NULL,
-    0, sysctl_devctl_queue, "I", "devctl queue length");
+SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_queue, CTLTYPE_INT | CTLFLAG_RW |
+    CTLFLAG_MPSAFE, NULL, 0, sysctl_devctl_queue, "I", "devctl queue length");
 
 static d_open_t                devopen;
 static d_close_t       devclose;
@@ -376,7 +377,6 @@ static d_poll_t             devpoll;
 
 static struct cdevsw dev_cdevsw = {
        .d_version =    D_VERSION,
-       .d_flags =      D_NEEDGIANT,
        .d_open =       devopen,
        .d_close =      devclose,
        .d_read =       devread,
@@ -420,23 +420,29 @@ devinit(void)
 static int
 devopen(struct cdev *dev, int oflags, int devtype, struct thread *td)
 {
-       if (devsoftc.inuse)
+
+       mtx_lock(&devsoftc.mtx);
+       if (devsoftc.inuse) {
+               mtx_unlock(&devsoftc.mtx);
                return (EBUSY);
+       }
        /* move to init */
        devsoftc.inuse = 1;
        devsoftc.nonblock = 0;
        devsoftc.async_proc = NULL;
+       mtx_unlock(&devsoftc.mtx);
        return (0);
 }
 
 static int
 devclose(struct cdev *dev, int fflag, int devtype, struct thread *td)
 {
-       devsoftc.inuse = 0;
+
        mtx_lock(&devsoftc.mtx);
+       devsoftc.inuse = 0;
+       devsoftc.async_proc = NULL;
        cv_broadcast(&devsoftc.cv);
        mtx_unlock(&devsoftc.mtx);
-       devsoftc.async_proc = NULL;
        return (0);
 }
 
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