Fix locking in input

[Pavel Machek <pavel@suse.cz>]

Hi!

input uses "volatile signed char" as a shared variable between normal
and interrupt threads (look at _sendbyte()). Thats bad idea, this
switches it to atomic_t.

I did not dare to store -1 o atomic ariable, that's why I switched -1
to +2.

I hope I do not break compilation somewhere, otherwise its trivial...

								Pavel

--- tmp/linux/drivers/input/keyboard/98kbd.c	2003-04-21 22:31:32.000000000 +0200
+++ linux/drivers/input/keyboard/98kbd.c	2003-11-22 16:36:39.000000000 +0100
@@ -100,7 +100,7 @@
 	char phys[32];
 	unsigned char cmdbuf[4];
 	unsigned char cmdcnt;
-	signed char ack;
+	atomic_t ack;
 	unsigned char shift;
 	struct {
 		unsigned char scancode;
@@ -118,10 +118,10 @@
 
 	switch (data) {
 		case KBD98_RET_ACK:
-			kbd98->ack = 1;
+			atomic_set(&kbd98->ack, 1);
 			return;
 		case KBD98_RET_NAK:
-			kbd98->ack = -1;
+			atomic_set(&kbd98->ack, 2);
 			return;
 	}
 
@@ -220,14 +220,14 @@
 static int kbd98_sendbyte(struct kbd98 *kbd98, unsigned char byte)
 {
 	int timeout = 10000; /* 100 msec */
-	kbd98->ack = 0;
+	atomic_set(&kbd98->ack, 0);
 
 	if (serio_write(kbd98->serio, byte))
 		return -1;
 
-	while (!kbd98->ack && timeout--) udelay(10);
+	while (!atomic_read(&kbd98->ack) && timeout--) udelay(10);
 
-	return -(kbd98->ack <= 0);
+	return -(atomic_read(&kbd98->ack) == 2);
 }
 
 /*
--- tmp/linux/drivers/input/keyboard/atkbd.c	2003-10-26 13:08:37.000000000 +0100
+++ linux/drivers/input/keyboard/atkbd.c	2003-11-22 16:36:30.000000000 +0100
@@ -145,7 +145,7 @@
 	unsigned char set;
 	unsigned char release;
 	int lastkey;
-	volatile signed char ack;
+	atomic_t ack;
 	unsigned char emul;
 	unsigned short id;
 	unsigned char write;
@@ -214,10 +214,10 @@
 
 	switch (code) {
 		case ATKBD_RET_ACK:
-			atkbd->ack = 1;
+			atomic_set(&atkbd->ack, 1);
 			goto out;
 		case ATKBD_RET_NAK:
-			atkbd->ack = -1;
+			atomic_set(&atkbd->ack, 2);
 			goto out;
 	}
 
@@ -294,7 +294,7 @@
 static int atkbd_sendbyte(struct atkbd *atkbd, unsigned char byte)
 {
 	int timeout = 20000; /* 200 msec */
-	atkbd->ack = 0;
+	atomic_set(&atkbd->ack, 0);
 
 #ifdef ATKBD_DEBUG
 	printk(KERN_DEBUG "atkbd.c: Sent: %02x\n", byte);
@@ -302,9 +302,9 @@
 	if (serio_write(atkbd->serio, byte))
 		return -1;
 
-	while (!atkbd->ack && timeout--) udelay(10);
+	while (!atomic_read(&atkbd->ack) && timeout--) udelay(10);
 
-	return -(atkbd->ack <= 0);
+	return -(atomic_read(&atkbd->ack) == 2);
 }
 
 /*
--- tmp/linux/drivers/input/mouse/psmouse-base.c	2003-09-28 22:05:48.000000000 +0200
+++ linux/drivers/input/mouse/psmouse-base.c	2003-11-22 16:15:12.000000000 +0100
@@ -121,13 +121,14 @@
 	if (psmouse->acking) {
 		switch (data) {
 			case PSMOUSE_RET_ACK:
-				psmouse->ack = 1;
+				atomic_set(&psmouse->ack, 1);
 				break;
 			case PSMOUSE_RET_NAK:
-				psmouse->ack = -1;
+				atomic_set(&psmouse->ack, 2);
 				break;
 			default:
-				psmouse->ack = 1;	/* Workaround for mice which don't ACK the Get ID command */
+				/* Workaround for mice which don't ACK the Get ID command */
+				atomic_set(&psmouse->ack, 1);
 				if (psmouse->cmdcnt)
 					psmouse->cmdbuf[--psmouse->cmdcnt] = data;
 				break;
@@ -197,7 +198,7 @@
 static int psmouse_sendbyte(struct psmouse *psmouse, unsigned char byte)
 {
 	int timeout = 10000; /* 100 msec */
-	psmouse->ack = 0;
+	atomic_set(&psmouse->ack, 0);
 	psmouse->acking = 1;
 
 	if (serio_write(psmouse->serio, byte)) {
@@ -205,9 +206,9 @@
 		return -1;
 	}
 
-	while (!psmouse->ack && timeout--) udelay(10);
+	while (!atomic_read(&psmouse->ack) && timeout--) udelay(10);
 
-	return -(psmouse->ack <= 0);
+	return -(atomic_read(&psmouse->ack) == 2);
 }
 
 /*
--- tmp/linux/drivers/input/mouse/psmouse.h	2003-09-28 22:05:48.000000000 +0200
+++ linux/drivers/input/mouse/psmouse.h	2003-11-22 16:08:01.000000000 +0100
@@ -37,7 +37,7 @@
 	unsigned long last;
 	unsigned char state;
 	char acking;
-	volatile char ack;
+	atomic_t ack;	/* This is being accessed without locking, at least make sure we do not run into alignment problems */
 	char error;
 	char devname[64];
 	char phys[32];

-- 
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