[PATCH 1/7] Use exported call to up/down read

[Mark Hills <mark-UrrBsZIrrsb10XsdtD+oqA@public.gmane.org>]

When building bcache as a module, the following errors are silenced
by this patch:

  ERROR: "call_rwsem_down_read_failed" [block/bcache.ko] undefined!
  ERROR: "call_rwsem_wake" [block/bcache.ko] undefined!

There may be implications of the extra code introduced by this, but
I am not familiar with these functions. Though I can confirm that
the resulting build seems to work.
---
 block/bcache.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/bcache.c b/block/bcache.c
index a2dbd1e..faaf75e 100644
--- a/block/bcache.c
+++ b/block/bcache.c
@@ -5561,7 +5561,7 @@ static void bio_complete(struct closure *cl)
 	keylist_free(&s->op.keys);
 
 	if (s->op.insert_type & INSERT_WRITE)
-		__up_read(&d->writeback_lock);
+		up_read(&d->writeback_lock);
 
 	if (s->cache_bio) {
 		int i;
@@ -5911,7 +5911,7 @@ static void request_write(struct search *s)
 	s->cl.fn		= bio_complete;
 	s->op.insert_type	= INSERT_WRITE;
 	check_should_skip(s);
-	__down_read(&s->op.d->writeback_lock);
+	down_read(&s->op.d->writeback_lock);
 
 	if (in_writeback(s->op.d, bio->bi_sector, bio_sectors(bio))) {
 		s->skip = false;
-- 
1.7.4.4