[34-longterm 101/247] isdn: hisax: Replace the bogus access to irq stats

Paul Gortmaker
2011-06-23T17:36:26Z

From: Thomas Gleixner <tglx@linutronix.de>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit 40f08a724fcc21285cf3a75aec957aef908605c6 upstream.

Abusing irq stats in a driver for counting interrupts is a horrible
idea and not safe with shared interrupts. Replace it by a local
interrupt counter.

Noticed by the attempt to remove the irq stats export.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/isdn/hisax/config.c | 18 ++++++++++++++----
drivers/isdn/hisax/hisax.h | 1 +
2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/isdn/hisax/config.c b/drivers/isdn/hisax/config.c
index 544cf4b..0a347a8 100644
--- a/drivers/isdn/hisax/config.c
+++ b/drivers/isdn/hisax/config.c
@@ -801,6 +801,16 @@ static void closecard(int cardnr)
ll_unload(csta);
}

+static irqreturn_t card_irq(int intno, void *dev_id)
+{
+ struct IsdnCardState *cs = dev_id;
+ irqreturn_t ret = cs->irq_func(intno, cs);
+
+ if (ret == IRQ_HANDLED)
+ cs->irq_cnt++;
+ return ret;
+}
+
static int init_card(struct IsdnCardState *cs)
{
int irq_cnt, cnt = 3, ret;
@@ -809,10 +819,10 @@ static int init_card(struct IsdnCardState *cs)
ret = cs->cardmsg(cs, CARD_INIT, NULL);
return(ret);
}
- irq_cnt = kstat_irqs(cs->irq);
+ irq_cnt = cs->irq_cnt = 0;
printk(KERN_INFO "%s: IRQ %d count %d\n", CardType[cs->typ],
cs->irq, irq_cnt);
- if (request_irq(cs->irq, cs->irq_func, cs->irq_flags, "HiSax", cs)) {
+ if (request_irq(cs->irq, card_irq, cs->irq_flags, "HiSax", cs)) {
printk(KERN_WARNING "HiSax: couldn't get interrupt %d\n",
cs->irq);
return 1;
@@ -822,8 +832,8 @@ static int init_card(struct IsdnCardState *cs)
/* Timeout 10ms */
msleep(10);
printk(KERN_INFO "%s: IRQ %d count %d\n",
- CardType[cs->typ], cs->irq, kstat_irqs(cs->irq));
- if (kstat_irqs(cs->irq) == irq_cnt) {
+ CardType[cs->typ], cs->irq, cs->irq_cnt);
+ if (cs->irq_cnt == irq_cnt) {
printk(KERN_WARNING
"%s: IRQ(%d) getting no interrupts during init %d\n",
CardType[cs->typ], cs->irq, 4 - cnt);
diff --git a/drivers/isdn/hisax/hisax.h b/drivers/isdn/hisax/hisax.h
index 832a878..32ab392 100644
--- a/drivers/isdn/hisax/hisax.h
+++ b/drivers/isdn/hisax/hisax.h
@@ -959,6 +959,7 @@ struct IsdnCardState {
u_long event;
struct work_struct tqueue;
struct timer_list dbusytimer;
+ unsigned int irq_cnt;
#ifdef ERROR_STATISTIC
int err_crc;
int err_tx;
--
1.7.4.4