code: drawterm

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devcons, devkbd: use tas() to check for unuse

--- a/kern/devcons.c

+++ b/kern/devcons.c

@@ -16,8 +16,7 @@

 Queue*	kbdq;			/* unprocessed console input */

 Queue*	lineq;			/* processed console input */

 Queue*	kprintoq;		/* console output, for /dev/kprint */

-long	kprintinuse;		/* test and set whether /dev/kprint is open */

-Lock	kprintlock;

+int	kprintinuse;		/* test and set whether /dev/kprint is open */

 int	panicking;

@@ -420,14 +419,10 @@

 		break;

 	case Qkprint:

-		lock(&kprintlock);

-		if(kprintinuse != 0){

+		if(tas(&kprintinuse) != 0){

 			c->flag &= ~COPEN;

-			unlock(&kprintlock);

 			error(Einuse);

 		}

-		kprintinuse = 1;

-		unlock(&kprintlock);

 		if(kprintoq == nil){

 			kprintoq = qopen(8*1024, Qcoalesce, 0, 0);

 			if(kprintoq == nil){

--- a/kern/devkbd.c

+++ b/kern/devkbd.c

@@ -69,11 +69,10 @@

 	c = devopen(c, omode, kbddir, nelem(kbddir), devgen);

 	switch((ulong)c->qid.path){

 	case Qkbd:

-		if(kbdinuse){

+		if(tas(&kbdinuse) != 0){

 			c->flag &= ~COPEN;

 			error(Einuse);

 		}

-		kbdinuse = 1;

 		break;

 	}

 	return c;