Re: 2.6.24-rc4-mm1 kobject changes broken with hvcs driver on powerpc

Balbir Singh
2007-12-06T18:20:37Z

Kamalesh Babulal wrote:
> Hi Andrew,
>
> The 2.6.24-rc4-mm1 kernel build fails with build failure,
>
> CC drivers/char/hvcs.o
> drivers/char/hvcs.c: In function ‘hvcs_open’:
> drivers/char/hvcs.c:1180: error: wrong type argument to unary exclamation mark
> make[2]: *** [drivers/char/hvcs.o] Error 1
> make[1]: *** [drivers/char] Error 2
> make: *** [drivers] Error 2
>
> The kref_get begin void return type, check for the kobject return type
> as in the previous kobject_get()
>
> if (!kref_get(&hvcsd->kref)) {
> spin_unlock_irqrestore(&hvcsd->lock, flags);
> printk(KERN_ERR "HVCS: Kobject of open"
> " hvcs doesn't exist.\n");
> return -EFAULT; /* Is this the right return value? */
> }
>
> I have tested for the build failure only.
>
> Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
> --
> --- linux-2.6.24-rc4/drivers/char/hvcs.c 2007-12-05 12:17:37.000000000 +0530
> +++ linux-2.6.24-rc4/drivers/char/~hvcs.c 2007-12-05 19:17:12.000000000 +0530
> @@ -1177,12 +1177,8 @@ fast_open:
> hvcsd = tty->driver_data;
>
> spin_lock_irqsave(&hvcsd->lock, flags);
> - if (!kref_get(&hvcsd->kref)) {
> - spin_unlock_irqrestore(&hvcsd->lock, flags);
> - printk(KERN_ERR "HVCS: Kobject of open"
> - " hvcs doesn't exist.\n");
> - return -EFAULT; /* Is this the right return value? */
> - }
> + kref_get(&hvcsd->kref);
> + spin_unlock_irqrestore(&hvcsd->lock, flags);
>

Why release the spinlock here? It's done after the count is incremented.
This patch does not seem correct.

> hvcsd->open_count++;
>

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL