Do not set IFF_DEBUG directly from the driver.

MFC after:	1 month.

2 files changed, 13 insertions, 7 deletions

diff --git a/sys/dev/cp/cpddk.h b/sys/dev/cp/cpddk.h
index 3ff40bb..fcdb0d0 100644
--- a/sys/dev/cp/cpddk.h
+++ b/sys/dev/cp/cpddk.h
@@ -205,6 +205,7 @@ typedef struct _cp_chan_t {
 	void *tag [NTBUF];		/* system dependent data per buffer */
 	void *sys;			/* system dependent data per channel */
 	unsigned char debug;		/* debug level, 0..2 */
+	unsigned char debug_shadow;	/* debug shadow */
 
 	void (*transmit) (struct _cp_chan_t *c, void *tag, int len);
 	void (*receive) (struct _cp_chan_t *c, unsigned char *data, int len);
diff --git a/sys/dev/cp/if_cp.c b/sys/dev/cp/if_cp.c
index dbe40bc..36b12ab 100644
--- a/sys/dev/cp/if_cp.c
+++ b/sys/dev/cp/if_cp.c
@@ -733,8 +733,8 @@ static int cp_sioctl (struct ifnet *ifp, u_long cmd, caddr_t data)
 
 	if (! (ifp->if_flags & IFF_DEBUG))
 		d->chan->debug = 0;
-	else if (! d->chan->debug)
-		d->chan->debug = 1;
+	else
+		d->chan->debug = d->chan->debug_shadow;
 
 	switch (cmd) {
 	default:	   CP_DEBUG2 (d, ("ioctl 0x%lx\n", cmd));   return 0;
@@ -1349,12 +1349,17 @@ static int cp_ioctl (struct cdev *dev, u_long cmd, caddr_t data, int flag, struc
 		error = priv_check (td, PRIV_DRIVER);
 		if (error)
 			return error;
-		d->chan->debug = *(int*)data;
 #ifndef	NETGRAPH
-		if (d->chan->debug)
-			d->ifp->if_flags |= IFF_DEBUG;
-		else
-			d->ifp->if_flags &= ~IFF_DEBUG;
+		/*
+		 * The debug_shadow is always greater than zero for logic 
+		 * simplicity.  For switching debug off the IFF_DEBUG is
+		 * responsible.
+		 */
+		d->chan->debug_shadow = (*(int*)data) ? (*(int*)data) : 1;
+		if (d->ifp->if_flags & IFF_DEBUG)
+			d->chan->debug = d->chan->debug_shadow;
+#else
+		d->chan->debug = *(int*)data;
 #endif
 		return 0;