Fix locking in input

From: Pavel Machek
Date: Sat Nov 22 2003 - 12:15:26 EST


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];

--
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
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