[PATCH 09/19] CacheFiles: Permit the page lock state to be monitored

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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 <[email protected]>
---

 include/linux/pagemap.h |    5 +++++
 mm/filemap.c            |   19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 24fdc48..a86693c 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -200,6 +200,11 @@ static inline void wait_on_page_fs_misc(
 extern void fastcall end_page_fs_misc(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 b9eb8b2..4c9c1ac 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -517,6 +517,25 @@ void fastcall wait_on_page_bit(struct pa
 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
  *
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux