iomap: pass private data to iomap_page_mkwrite

Allow the file system to pass private data which can be used by the
iomap_begin and iomap_end methods through the private pointer in the
iomap_iter structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250206064035.2323428-10-hch@lst.de
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Christoph Hellwig

fs/iomap/buffered-io.c

@@ -1489,11 +1489,13 @@ static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter,
 	return length;
 }
 
-vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
+vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops,
+		void *private)
 {
 	struct iomap_iter iter = {
 		.inode		= file_inode(vmf->vma->vm_file),
 		.flags		= IOMAP_WRITE | IOMAP_FAULT,
+		.private	= private,
 	};
 	struct folio *folio = page_folio(vmf->page);
 	ssize_t ret;

fs/xfs/xfs_file.c

@@ -1511,7 +1511,8 @@ xfs_write_fault(
 	if (IS_DAX(inode))
 		ret = xfs_dax_fault_locked(vmf, order, true);
 	else
-		ret = iomap_page_mkwrite(vmf, &xfs_buffered_write_iomap_ops);
+		ret = iomap_page_mkwrite(vmf, &xfs_buffered_write_iomap_ops,
+				NULL);
 	xfs_iunlock(ip, lock_mode);
 
 	sb_end_pagefault(inode->i_sb);

fs/zonefs/file.c

@@ -299,7 +299,7 @@ static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
 
 	/* Serialize against truncates */
 	filemap_invalidate_lock_shared(inode->i_mapping);
-	ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
+	ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops, NULL);
 	filemap_invalidate_unlock_shared(inode->i_mapping);
 
 	sb_end_pagefault(inode->i_sb);

include/linux/iomap.h

@@ -316,9 +316,8 @@ int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
 		bool *did_zero, const struct iomap_ops *ops);
 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
 		const struct iomap_ops *ops);
-vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
-			const struct iomap_ops *ops);
-
+vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops,
+		void *private);
 typedef void (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length,
 		struct iomap *iomap);
 void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte,