nfs: move nfs_wait_on_request to write.c

nfs_wait_on_request is now only used in write.c.  Move it there
and mark it static.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Author: Christoph Hellwig

fs/nfs/pagelist.c

@@ -598,25 +598,6 @@ void nfs_release_request(struct nfs_page *req)
 }
 EXPORT_SYMBOL_GPL(nfs_release_request);
 
-/**
- * nfs_wait_on_request - Wait for a request to complete.
- * @req: request to wait upon.
- *
- * Interruptible by fatal signals only.
- * The user is responsible for holding a count on the request.
- */
-int
-nfs_wait_on_request(struct nfs_page *req)
-{
-	if (!test_bit(PG_BUSY, &req->wb_flags))
-		return 0;
-	set_bit(PG_CONTENDED2, &req->wb_flags);
-	smp_mb__after_atomic();
-	return wait_on_bit_io(&req->wb_flags, PG_BUSY,
-			      TASK_UNINTERRUPTIBLE);
-}
-EXPORT_SYMBOL_GPL(nfs_wait_on_request);
-
 /*
  * nfs_generic_pg_test - determine if requests can be coalesced
  * @desc: pointer to descriptor

fs/nfs/write.c

@@ -478,6 +478,23 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
 	nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 }
 
+/**
+ * nfs_wait_on_request - Wait for a request to complete.
+ * @req: request to wait upon.
+ *
+ * Interruptible by fatal signals only.
+ * The user is responsible for holding a count on the request.
+ */
+static int nfs_wait_on_request(struct nfs_page *req)
+{
+	if (!test_bit(PG_BUSY, &req->wb_flags))
+		return 0;
+	set_bit(PG_CONTENDED2, &req->wb_flags);
+	smp_mb__after_atomic();
+	return wait_on_bit_io(&req->wb_flags, PG_BUSY,
+			      TASK_UNINTERRUPTIBLE);
+}
+
 /*
  * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req
  * @head: head request of page group, must be holding head lock

include/linux/nfs_page.h

@@ -152,7 +152,6 @@ extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 				struct nfs_page *prev,
 				struct nfs_page *req);
-extern  int nfs_wait_on_request(struct nfs_page *);
 extern	void nfs_unlock_request(struct nfs_page *req);
 extern	void nfs_unlock_and_release_request(struct nfs_page *);
 extern void nfs_join_page_group(struct nfs_page *head,