1 files changed, 53 insertions, 0 deletions
diff --git a/fs/xfs/xfs_bio_io.c b/fs/xfs/xfs_bio_io.c
new file mode 100644
index 000000000000..2a736d10eafb
--- /dev/null
+++ b/fs/xfs/xfs_bio_io.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Christoph Hellwig.
+ */
+#include "xfs.h"
+
+static inline unsigned int bio_max_vecs(unsigned int count)
+{
+	return bio_max_segs(howmany(count, PAGE_SIZE));
+}
+
+int
+xfs_rw_bdev(
+	struct block_device	*bdev,
+	sector_t		sector,
+	unsigned int		count,
+	char			*data,
+	enum req_op		op)
+
+{
+	unsigned int		done = 0, added;
+	int			error;
+	struct bio		*bio;
+
+	op |= REQ_META | REQ_SYNC;
+	if (!is_vmalloc_addr(data))
+		return bdev_rw_virt(bdev, sector, data, count, op);
+
+	bio = bio_alloc(bdev, bio_max_vecs(count), op, GFP_KERNEL);
+	bio->bi_iter.bi_sector = sector;
+
+	do {
+		added = bio_add_vmalloc_chunk(bio, data + done, count - done);
+		if (!added) {
+			struct bio	*prev = bio;
+
+			bio = bio_alloc(prev->bi_bdev,
+					bio_max_vecs(count - done),
+					prev->bi_opf, GFP_KERNEL);
+			bio->bi_iter.bi_sector = bio_end_sector(prev);
+			bio_chain(prev, bio);
+			submit_bio(prev);
+		}
+		done += added;
+	} while (done < count);
+
+	error = submit_bio_wait(bio);
+	bio_put(bio);
+
+	if (op == REQ_OP_READ)
+		invalidate_kernel_vmap_range(data, count);
+	return error;
+}