iomap: Convert iomap_write_end types

iomap_write_end cannot return an error, so switch it to return
size_t instead of int and remove the error checking from the callers.
Also convert the arguments to size_t from unsigned int, in case anyone
ever wants to support a page size larger than 2GB.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/iomap/buffered-io.c

@@ -663,9 +663,8 @@ iomap_set_page_dirty(struct page *page)
 }
 EXPORT_SYMBOL_GPL(iomap_set_page_dirty);
 
-static int
-__iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
-		unsigned copied, struct page *page)
+static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
+		size_t copied, struct page *page)
 {
 	flush_dcache_page(page);
 
@@ -687,9 +686,8 @@ __iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
 	return copied;
 }
 
-static int
-iomap_write_end_inline(struct inode *inode, struct page *page,
-		struct iomap *iomap, loff_t pos, unsigned copied)
+static size_t iomap_write_end_inline(struct inode *inode, struct page *page,
+		struct iomap *iomap, loff_t pos, size_t copied)
 {
 	void *addr;
 
@@ -705,13 +703,14 @@ iomap_write_end_inline(struct inode *inode, struct page *page,
 	return copied;
 }
 
-static int
-iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied,
-		struct page *page, struct iomap *iomap, struct iomap *srcmap)
+/* Returns the number of bytes copied.  May be 0.  Cannot be an errno. */
+static size_t iomap_write_end(struct inode *inode, loff_t pos, size_t len,
+		size_t copied, struct page *page, struct iomap *iomap,
+		struct iomap *srcmap)
 {
 	const struct iomap_page_ops *page_ops = iomap->page_ops;
 	loff_t old_size = inode->i_size;
-	int ret;
+	size_t ret;
 
 	if (srcmap->type == IOMAP_INLINE) {
 		ret = iomap_write_end_inline(inode, page, iomap, pos, copied);
@@ -790,11 +789,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 
 		copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
 
-		status = iomap_write_end(inode, pos, bytes, copied, page, iomap,
+		copied = iomap_write_end(inode, pos, bytes, copied, page, iomap,
 				srcmap);
-		if (unlikely(status < 0))
-			break;
-		copied = status;
 
 		cond_resched();
 
@@ -868,11 +864,8 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 
 		status = iomap_write_end(inode, pos, bytes, bytes, page, iomap,
 				srcmap);
-		if (unlikely(status <= 0)) {
-			if (WARN_ON_ONCE(status == 0))
-				return -EIO;
-			return status;
-		}
+		if (WARN_ON_ONCE(status == 0))
+			return -EIO;
 
 		cond_resched();