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Subject[PATCH] adbhid preempt/smp races
From
Date
Hi !

This patch fixes a few races in the LED code of the adbhid driver
that would affect SMP or preempt.

Please apply,
Ben.

diff -urN linux-2.5/drivers/macintosh/adbhid.c linuxppc-2.5-benh/drivers/macintosh/adbhid.c
--- linux-2.5/drivers/macintosh/adbhid.c 2004-03-01 18:11:44.000000000 +1100
+++ linuxppc-2.5-benh/drivers/macintosh/adbhid.c 2004-03-25 16:16:56.000000000 +1100
@@ -107,7 +107,6 @@
static void adbhid_probe(void);

static void adbhid_input_keycode(int, int, int, struct pt_regs *);
-static void leds_done(struct adb_request *);

static void init_trackpad(int id);
static void init_trackball(int id);
@@ -446,24 +445,54 @@

static struct adb_request led_request;
static int leds_pending[16];
+static int leds_req_pending;
static int pending_devs[16];
static int pending_led_start=0;
static int pending_led_end=0;
+static spinlock_t leds_lock = SPIN_LOCK_UNLOCKED;
+
+static void leds_done(struct adb_request *req)
+{
+ int leds, device;
+ unsigned long flags;
+
+ spin_lock_irqsave(&leds_lock, flags);
+
+ if (pending_led_start != pending_led_end) {
+ device = pending_devs[pending_led_start];
+ leds = leds_pending[device] & 0xff;
+ leds_pending[device] = 0;
+ pending_led_start++;
+ pending_led_start = (pending_led_start < 16) ? pending_led_start : 0;
+ } else
+ leds_req_pending = 0;
+
+ spin_unlock_irqrestore(&leds_lock, flags);
+ if (leds_req_pending)
+ adb_request(&led_request, leds_done, 0, 3,
+ ADB_WRITEREG(device, KEYB_LEDREG), 0xff, ~leds);
+}

static void real_leds(unsigned char leds, int device)
{
- if (led_request.complete) {
- adb_request(&led_request, leds_done, 0, 3,
- ADB_WRITEREG(device, KEYB_LEDREG), 0xff,
- ~leds);
- } else {
- if (!(leds_pending[device] & 0x100)) {
- pending_devs[pending_led_end] = device;
- pending_led_end++;
- pending_led_end = (pending_led_end < 16) ? pending_led_end : 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&leds_lock, flags);
+ if (!leds_req_pending) {
+ leds_req_pending = 1;
+ spin_unlock_irqrestore(&leds_lock, flags);
+ adb_request(&led_request, leds_done, 0, 3,
+ ADB_WRITEREG(device, KEYB_LEDREG), 0xff, ~leds);
+ return;
+ } else {
+ if (!(leds_pending[device] & 0x100)) {
+ pending_devs[pending_led_end] = device;
+ pending_led_end++;
+ pending_led_end = (pending_led_end < 16) ? pending_led_end : 0;
+ }
+ leds_pending[device] = leds | 0x100;
}
- leds_pending[device] = leds | 0x100;
- }
+ spin_unlock_irqrestore(&leds_lock, flags);
}

/*
@@ -487,21 +516,6 @@
return -1;
}

-static void leds_done(struct adb_request *req)
-{
- int leds,device;
-
- if (pending_led_start != pending_led_end) {
- device = pending_devs[pending_led_start];
- leds = leds_pending[device] & 0xff;
- leds_pending[device] = 0;
- pending_led_start++;
- pending_led_start = (pending_led_start < 16) ? pending_led_start : 0;
- real_leds(leds,device);
- }
-
-}
-
static int
adb_message_handler(struct notifier_block *this, unsigned long code, void *x)
{
@@ -518,7 +532,7 @@
}

/* Stop pending led requests */
- while(!led_request.complete)
+ while(leds_req_pending)
adb_poll();
break;


-
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