writeback: wbc_attach_fdatawrite_inode out of line

This allows exporting this high-level interface only while keeping
wbc_attach_and_unlock_inode private in fs-writeback.c and unexporting
__inode_attach_wb.

Signed-off-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

Author: Christoph Hellwig

fs/fs-writeback.c

@@ -290,7 +290,6 @@ void __inode_attach_wb(struct inode *inode, struct folio *folio)
 	if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
 		wb_put(wb);
 }
-EXPORT_SYMBOL_GPL(__inode_attach_wb);
 
 /**
  * inode_cgwb_move_to_attached - put the inode onto wb->b_attached list
@@ -731,8 +730,8 @@ bool cleanup_offline_cgwb(struct bdi_writeback *wb)
  * writeback completion, wbc_detach_inode() should be called.  This is used
  * to track the cgroup writeback context.
  */
-void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
-				 struct inode *inode)
+static void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
+		struct inode *inode)
 	__releases(&inode->i_lock)
 {
 	if (!inode_cgwb_enabled(inode)) {
@@ -763,7 +762,24 @@ void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
 	if (unlikely(wb_dying(wbc->wb) && !css_is_dying(wbc->wb->memcg_css)))
 		inode_switch_wbs(inode, wbc->wb_id);
 }
-EXPORT_SYMBOL_GPL(wbc_attach_and_unlock_inode);
+
+/**
+ * wbc_attach_fdatawrite_inode - associate wbc and inode for fdatawrite
+ * @wbc: writeback_control of interest
+ * @inode: target inode
+ *
+ * This function is to be used by __filemap_fdatawrite_range(), which is an
+ * alternative entry point into writeback code, and first ensures @inode is
+ * associated with a bdi_writeback and attaches it to @wbc.
+ */
+void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
+		struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	inode_attach_wb(inode, NULL);
+	wbc_attach_and_unlock_inode(wbc, inode);
+}
+EXPORT_SYMBOL_GPL(wbc_attach_fdatawrite_inode);
 
 /**
  * wbc_detach_inode - disassociate wbc from inode and perform foreign detection
@@ -1228,6 +1244,13 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 	}
 }
 
+static inline void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
+					       struct inode *inode)
+	__releases(&inode->i_lock)
+{
+	spin_unlock(&inode->i_lock);
+}
+
 #endif	/* CONFIG_CGROUP_WRITEBACK */
 
 /*

include/linux/writeback.h

@@ -213,9 +213,6 @@ static inline void wait_on_inode(struct inode *inode)
 #include <linux/bio.h>
 
 void __inode_attach_wb(struct inode *inode, struct folio *folio);
-void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
-				 struct inode *inode)
-	__releases(&inode->i_lock);
 void wbc_detach_inode(struct writeback_control *wbc);
 void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page,
 			      size_t bytes);
@@ -254,22 +251,8 @@ static inline void inode_detach_wb(struct inode *inode)
 	}
 }
 
-/**
- * wbc_attach_fdatawrite_inode - associate wbc and inode for fdatawrite
- * @wbc: writeback_control of interest
- * @inode: target inode
- *
- * This function is to be used by __filemap_fdatawrite_range(), which is an
- * alternative entry point into writeback code, and first ensures @inode is
- * associated with a bdi_writeback and attaches it to @wbc.
- */
-static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
-					       struct inode *inode)
-{
-	spin_lock(&inode->i_lock);
-	inode_attach_wb(inode, NULL);
-	wbc_attach_and_unlock_inode(wbc, inode);
-}
+void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
+		struct inode *inode);
 
 /**
  * wbc_init_bio - writeback specific initializtion of bio
@@ -303,13 +286,6 @@ static inline void inode_detach_wb(struct inode *inode)
 {
 }
 
-static inline void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
-					       struct inode *inode)
-	__releases(&inode->i_lock)
-{
-	spin_unlock(&inode->i_lock);
-}
-
 static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
 					       struct inode *inode)
 {