vfs: remove unused wrapper block_page_mkwrite()

The function currently called "__block_page_mkwrite()" used to be called
"block_page_mkwrite()" until a wrapper for this function was added by:

commit 24da4fab ("vfs: Create __block_page_mkwrite() helper passing
	error values back")

This wrapper, the current "block_page_mkwrite()", is currently unused.
__block_page_mkwrite() is used directly by ext4, nilfs2 and xfs.

Remove the unused wrapper, rename __block_page_mkwrite() back to
block_page_mkwrite() and update the comment above block_page_mkwrite().
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/buffer.c

@@ -2420,9 +2420,9 @@ EXPORT_SYMBOL(block_commit_write);
  * unlock the page.
  *
  * Direct callers of this function should protect against filesystem freezing
- * using sb_start_write() - sb_end_write() functions.
+ * using sb_start_pagefault() - sb_end_pagefault() functions.
  */
-int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
+int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 			 get_block_t get_block)
 {
 	struct page *page = vmf->page;
@@ -2459,26 +2459,6 @@ int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 	unlock_page(page);
 	return ret;
 }
-EXPORT_SYMBOL(__block_page_mkwrite);
-
-int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
-		   get_block_t get_block)
-{
-	int ret;
-	struct super_block *sb = file_inode(vma->vm_file)->i_sb;
-
-	sb_start_pagefault(sb);
-
-	/*
-	 * Update file times before taking page lock. We may end up failing the
-	 * fault so this update may be superfluous but who really cares...
-	 */
-	file_update_time(vma->vm_file);
-
-	ret = __block_page_mkwrite(vma, vmf, get_block);
-	sb_end_pagefault(sb);
-	return block_page_mkwrite_return(ret);
-}
 EXPORT_SYMBOL(block_page_mkwrite);
 
 /*

fs/ext4/inode.c

@@ -5283,7 +5283,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	    !ext4_should_journal_data(inode) &&
 	    !ext4_nonda_switch(inode->i_sb)) {
 		do {
-			ret = __block_page_mkwrite(vma, vmf,
+			ret = block_page_mkwrite(vma, vmf,
 						   ext4_da_get_block_prep);
 		} while (ret == -ENOSPC &&
 		       ext4_should_retry_alloc(inode->i_sb, &retries));
@@ -5330,7 +5330,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 		ret = VM_FAULT_SIGBUS;
 		goto out;
 	}
-	ret = __block_page_mkwrite(vma, vmf, get_block);
+	ret = block_page_mkwrite(vma, vmf, get_block);
 	if (!ret && ext4_should_journal_data(inode)) {
 		if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
 			  PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {

fs/nilfs2/file.c

@@ -109,7 +109,7 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 		goto out;
 
 	file_update_time(vma->vm_file);
-	ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
+	ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 	if (ret) {
 		nilfs_transaction_abort(inode->i_sb);
 		goto out;

fs/xfs/xfs_file.c

@@ -1506,7 +1506,7 @@ xfs_filemap_page_mkwrite(
 		ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_direct,
 				    xfs_end_io_dax_write);
 	} else {
-		ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
+		ret = block_page_mkwrite(vma, vmf, xfs_get_blocks);
 		ret = block_page_mkwrite_return(ret);
 	}
 

include/linux/buffer_head.h

@@ -227,8 +227,6 @@ int cont_write_begin(struct file *, struct address_space *, loff_t,
 			get_block_t *, loff_t *);
 int generic_cont_expand_simple(struct inode *inode, loff_t size);
 int block_commit_write(struct page *page, unsigned from, unsigned to);
-int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
-				get_block_t get_block);
 int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 				get_block_t get_block);
 /* Convert errno to return value from ->page_mkwrite() call */