In order to allow for interruptible and asynchronous versions of
lock_page in conjunction with the wait_on_bit changes, we need to
define low-level lock page routines which take an additional
argument, i.e a wait queue entry and may return non-zero status,
e.g -EINTR, -EIOCBRETRY, -EWOULDBLOCK etc. This patch renames 
__lock_page to lock_page_slow, so that __lock_page and 
__lock_page_slow can denote the versions which take a wait queue 
parameter.

Signed-off-by: Suparna Bhattacharya <suparna@in.ibm.com>

diff -puN include/linux/pagemap.h~lock_page_slow include/linux/pagemap.h
---

 linux-2.6.20-rc1-root/include/linux/pagemap.h |    4 ++--
 linux-2.6.20-rc1-root/mm/filemap.c            |    8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff -puN include/linux/pagemap.h~lock_page_slow include/linux/pagemap.h
--- linux-2.6.20-rc1/include/linux/pagemap.h~lock_page_slow	2006-12-19 15:50:03.000000000 +0530
+++ linux-2.6.20-rc1-root/include/linux/pagemap.h	2006-12-20 13:45:20.000000000 +0530
@@ -133,7 +133,7 @@ static inline pgoff_t linear_page_index(
 	return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 }
 
-extern void FASTCALL(__lock_page(struct page *page));
+extern void FASTCALL(lock_page_slow(struct page *page));
 extern void FASTCALL(__lock_page_nosync(struct page *page));
 extern void FASTCALL(unlock_page(struct page *page));
 
@@ -144,7 +144,7 @@ static inline void lock_page(struct page
 {
 	might_sleep();
 	if (TestSetPageLocked(page))
-		__lock_page(page);
+		lock_page_slow(page);
 }
 
 /*
diff -puN mm/filemap.c~lock_page_slow mm/filemap.c
--- linux-2.6.20-rc1/mm/filemap.c~lock_page_slow	2006-12-19 15:50:03.000000000 +0530
+++ linux-2.6.20-rc1-root/mm/filemap.c	2006-12-20 13:45:20.000000000 +0530
@@ -556,7 +556,7 @@ void end_page_writeback(struct page *pag
 EXPORT_SYMBOL(end_page_writeback);
 
 /**
- * __lock_page - get a lock on the page, assuming we need to sleep to get it
+ * lock_page_slow - get a lock on the page, assuming we need to sleep to get it
  * @page: the page to lock
  *
  * Ugly. Running sync_page() in state TASK_UNINTERRUPTIBLE is scary.  If some
@@ -564,14 +564,14 @@ EXPORT_SYMBOL(end_page_writeback);
  * chances are that on the second loop, the block layer's plug list is empty,
  * so sync_page() will then return in state TASK_UNINTERRUPTIBLE.
  */
-void fastcall __lock_page(struct page *page)
+void fastcall lock_page_slow(struct page *page)
 {
 	DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
 
 	__wait_on_bit_lock(page_waitqueue(page), &wait, sync_page,
 							TASK_UNINTERRUPTIBLE);
 }
-EXPORT_SYMBOL(__lock_page);
+EXPORT_SYMBOL(lock_page_slow);
 
 /*
  * Variant of lock_page that does not require the caller to hold a reference
@@ -647,7 +647,7 @@ repeat:
 		page_cache_get(page);
 		if (TestSetPageLocked(page)) {
 			read_unlock_irq(&mapping->tree_lock);
-			__lock_page(page);
+			lock_page_slow(page);
 			read_lock_irq(&mapping->tree_lock);
 
 			/* Has the page been truncated while we slept? */
_