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| author | David Howells <dhowells@redhat.com> | 2009-04-03 19:42:39 +0400 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2009-04-03 19:42:39 +0400 |
| commit | 385e1ca5f21c4680ad6a46a3aa2ea8af99e99c92 (patch) | |
| tree | 7d887b59d943c5dd62c9604b7ea37fd2d650df71 | |
| parent | b510882281d56873e1194021643b7c325336f84f (diff) | |
| download | linux-385e1ca5f21c4680ad6a46a3aa2ea8af99e99c92.tar.xz | |
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 <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
| -rw-r--r-- | include/linux/pagemap.h | 5 | ||||
| -rw-r--r-- | mm/filemap.c | 18 |
2 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 076a7dc67c2b..34da5230faab 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 cbc5772e7171..fc11974f2bee 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 * |