From: David Howells Date: Fri, 3 Apr 2009 15:42:39 +0000 (+0100) Subject: CacheFiles: Permit the page lock state to be monitored X-Git-Tag: v3.12-rc1~15202^2~20 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=385e1ca5f21c4680ad6a46a3aa2ea8af99e99c92;p=kernel%2Fkernel-generic.git CacheFiles: Permit the page lock state to be monitored Add a function to install a monitor on the page lock waitqueue for a particular page, thus allowing the page being unlocked to be detected. This is used by CacheFiles to detect read completion on a page in the backing filesystem so that it can then copy the data to the waiting netfs page. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Rik van Riel Acked-by: Al Viro Tested-by: Daire Byrne --- diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 076a7dc6..34da523 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -384,6 +384,11 @@ static inline void wait_on_page_writeback(struct page *page) extern void end_page_writeback(struct page *page); /* + * Add an arbitrary waiter to a page's wait queue + */ +extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter); + +/* * Fault a userspace page into pagetables. Return non-zero on a fault. * * This assumes that two userspace pages are always sufficient. That's diff --git a/mm/filemap.c b/mm/filemap.c index cbc5772..fc11974 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -565,6 +565,24 @@ void wait_on_page_bit(struct page *page, int bit_nr) EXPORT_SYMBOL(wait_on_page_bit); /** + * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue + * @page - Page defining the wait queue of interest + * @waiter - Waiter to add to the queue + * + * Add an arbitrary @waiter to the wait queue for the nominated @page. + */ +void add_page_wait_queue(struct page *page, wait_queue_t *waiter) +{ + wait_queue_head_t *q = page_waitqueue(page); + unsigned long flags; + + spin_lock_irqsave(&q->lock, flags); + __add_wait_queue(q, waiter); + spin_unlock_irqrestore(&q->lock, flags); +} +EXPORT_SYMBOL_GPL(add_page_wait_queue); + +/** * unlock_page - unlock a locked page * @page: the page *