fs: Pass an iocb to generic_perform_write()

We can extract both the file pointer and the pos from the iocb.
This simplifies each caller as well as allowing generic_perform_write()
to see more of the iocb contents in the future.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Matthew Wilcox (Oracle)

fs/ceph/file.c

@@ -1869,7 +1869,7 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		 * are pending vmtruncate. So write and vmtruncate
 		 * can not run at the same time
 		 */
-		written = generic_perform_write(file, from, pos);
+		written = generic_perform_write(iocb, from);
 		if (likely(written >= 0))
 			iocb->ki_pos = pos + written;
 		ceph_end_io_write(inode);

fs/ext4/file.c

@@ -267,7 +267,7 @@ static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
 		goto out;
 
 	current->backing_dev_info = inode_to_bdi(inode);
-	ret = generic_perform_write(iocb->ki_filp, from, iocb->ki_pos);
+	ret = generic_perform_write(iocb, from);
 	current->backing_dev_info = NULL;
 
 out:

fs/f2fs/file.c

@@ -4448,7 +4448,7 @@ static ssize_t f2fs_buffered_write_iter(struct kiocb *iocb,
 		return -EOPNOTSUPP;
 
 	current->backing_dev_info = inode_to_bdi(inode);
-	ret = generic_perform_write(file, from, iocb->ki_pos);
+	ret = generic_perform_write(iocb, from);
 	current->backing_dev_info = NULL;
 
 	if (ret > 0) {

fs/nfs/file.c

@@ -646,7 +646,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 	result = generic_write_checks(iocb, from);
 	if (result > 0) {
 		current->backing_dev_info = inode_to_bdi(inode);
-		result = generic_perform_write(file, from, iocb->ki_pos);
+		result = generic_perform_write(iocb, from);
 		current->backing_dev_info = NULL;
 	}
 	nfs_end_io_write(inode);

include/linux/fs.h

@@ -2999,7 +2999,7 @@ extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
-extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
+ssize_t generic_perform_write(struct kiocb *, struct iov_iter *);
 
 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
 		rwf_t flags);

mm/filemap.c

@@ -3752,9 +3752,10 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 }
 EXPORT_SYMBOL(generic_file_direct_write);
 
-ssize_t generic_perform_write(struct file *file,
-				struct iov_iter *i, loff_t pos)
+ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i)
 {
+	struct file *file = iocb->ki_filp;
+	loff_t pos = iocb->ki_pos;
 	struct address_space *mapping = file->f_mapping;
 	const struct address_space_operations *a_ops = mapping->a_ops;
 	long status = 0;
@@ -3884,7 +3885,8 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		if (written < 0 || !iov_iter_count(from) || IS_DAX(inode))
 			goto out;
 
-		status = generic_perform_write(file, from, pos = iocb->ki_pos);
+		pos = iocb->ki_pos;
+		status = generic_perform_write(iocb, from);
 		/*
 		 * If generic_perform_write() returned a synchronous error
 		 * then we want to return the number of bytes which were
@@ -3916,7 +3918,7 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			 */
 		}
 	} else {
-		written = generic_perform_write(file, from, iocb->ki_pos);
+		written = generic_perform_write(iocb, from);
 		if (likely(written > 0))
 			iocb->ki_pos += written;
 	}