MM: export page_wakeup functions
This will allow NFS to wait for PG_private to be cleared and,
particularly, to send a wake-up when it is.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 87f9e42..2dca0ce 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -496,8 +496,8 @@
}
/*
- * This is exported only for wait_on_page_locked/wait_on_page_writeback.
- * Never use this directly!
+ * This is exported only for wait_on_page_locked/wait_on_page_writeback,
+ * and for filesystems which need to wait on PG_private.
*/
extern void wait_on_page_bit(struct page *page, int bit_nr);
@@ -512,6 +512,12 @@
return 0;
}
+extern wait_queue_head_t *page_waitqueue(struct page *page);
+static inline void wake_up_page(struct page *page, int bit)
+{
+ __wake_up_bit(page_waitqueue(page), &page->flags, bit);
+}
+
/*
* Wait for a page to be unlocked.
*
diff --git a/mm/filemap.c b/mm/filemap.c
index cbe5a90..b9b1413 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -670,17 +670,13 @@
* at a cost of "thundering herd" phenomena during rare hash
* collisions.
*/
-static wait_queue_head_t *page_waitqueue(struct page *page)
+wait_queue_head_t *page_waitqueue(struct page *page)
{
const struct zone *zone = page_zone(page);
return &zone->wait_table[hash_ptr(page, zone->wait_table_bits)];
}
-
-static inline void wake_up_page(struct page *page, int bit)
-{
- __wake_up_bit(page_waitqueue(page), &page->flags, bit);
-}
+EXPORT_SYMBOL(page_waitqueue);
void wait_on_page_bit(struct page *page, int bit_nr)
{