unlock_page — unlock a locked page
void unlock_page ( | struct page * page); |
Unlocks the page and wakes up sleepers in ___wait_on_page_locked.
Also wakes sleepers in wait_on_page_writeback because the wakeup
mechanism between PageLocked pages and PageWriteback pages is shared.
But that's OK - sleepers in wait_on_page_writeback just go back to sleep.
The mb is necessary to enforce ordering between the clear_bit and the read
of the waitqueue (to avoid SMP races with a parallel wait_on_page_locked).