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authorDavid Howells <dhowells@redhat.com>2009-04-03 16:42:39 +0100
committerDavid Howells <dhowells@redhat.com>2009-04-03 16:42:39 +0100
commit385e1ca5f21c4680ad6a46a3aa2ea8af99e99c92 (patch)
tree7d887b59d943c5dd62c9604b7ea37fd2d650df71 /mm/filemap.c
parentb510882281d56873e1194021643b7c325336f84f (diff)
downloadconfigs-385e1ca5f21c4680ad6a46a3aa2ea8af99e99c92.tar.gz
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>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index cbc5772e717..fc11974f2be 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
*