Hi Hari, On Tue, Apr 7, 2009 at 11:59 PM, Kanigeri, Hari <[email protected]> wrote: > Ameya, > >> >> get_page() function has following check inside it: >> VM_BUG_ON(atomic_read(&page->_count) == 0); >> >> Why we need to repeat it again? >> I guess we can completely remove following check which is in my >> opinion completely >> redundant: > > -- This check in get_page is conditional check and this is to catch the cases > when page >count starts with "0", which I think is still a possible condition > if the user space buffer >was never touched. So I am not sure if we can rely > on this.
Thanks for the explanation :) I missed the point that VM_BUG_ON is a conditional check. So ideally user space process should touch all the buffers before sending them to bridge driver so that page_count is never zero? Also I didn't understand the meaning of the following message which is printed by printk when page_count is less than 1. "Trying to fix it up, but a reboot is needed\n" Where the fixing effort is happening? Cheers, Ameya. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
