powerpc: hv{cs, si}_close() both unsigned hp->count and hvcsd->open_count cannot be negative

[roel kluin]

unsigned hp->count and hvcsd->open_count cannot be negative

Signed-off-by: Roel Kluin <[EMAIL PROTECTED]>
---
Both members of respectively struct hvcs_struct, see
vi drivers/char/hvcs.c +262

and struct hvcs_struct, see
vi drivers/char/hvsi.c +70

diff --git a/drivers/char/hvcs.c b/drivers/char/hvcs.c
index 473d9b1..b228b84 100644
--- a/drivers/char/hvcs.c
+++ b/drivers/char/hvcs.c
@@ -1222,7 +1222,8 @@ static void hvcs_close(struct tty_struct *tty, struct 
file *filp)
        hvcsd = tty->driver_data;
 
        spin_lock_irqsave(&hvcsd->lock, flags);
-       if (--hvcsd->open_count == 0) {
+       if (hvcsd->open_count == 1) {
+               hvcsd->open_count--;
 
                vio_disable_interrupts(hvcsd->vdev);
 
@@ -1248,7 +1249,9 @@ static void hvcs_close(struct tty_struct *tty, struct 
file *filp)
                free_irq(irq, hvcsd);
                kref_put(&hvcsd->kref, destroy_hvcs_struct);
                return;
-       } else if (hvcsd->open_count < 0) {
+       } else if (hvcsd->open_count > 1) {
+               hvcsd->open_count--;
+       } else {
                printk(KERN_ERR "HVCS: [EMAIL PROTECTED] open_count: %d"
                                " is missmanaged.\n",
                hvcsd->vdev->unit_address, hvcsd->open_count);
diff --git a/drivers/char/hvsi.c b/drivers/char/hvsi.c
index 59c6f9a..d46bccd 100644
--- a/drivers/char/hvsi.c
+++ b/drivers/char/hvsi.c
@@ -875,7 +875,8 @@ static void hvsi_close(struct tty_struct *tty, struct file 
*filp)
 
        spin_lock_irqsave(&hp->lock, flags);
 
-       if (--hp->count == 0) {
+       if (hp->count == 1) {
+               hp->count--;
                hp->tty = NULL;
                hp->inbuf_end = hp->inbuf; /* discard remaining partial packets 
*/
 
@@ -908,7 +909,9 @@ static void hvsi_close(struct tty_struct *tty, struct file 
*filp)
 
                        spin_lock_irqsave(&hp->lock, flags);
                }
-       } else if (hp->count < 0)
+       } else if (hp->count > 1)
+               hp->count--;
+       else
                printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
                       hp - hvsi_ports, hp->count);
 
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