1 files changed, 71 insertions, 0 deletions
diff --git a/drivers/md/dm-bio-record.h b/drivers/md/dm-bio-record.h
new file mode 100644
index 00000000..3a8cfa26
--- /dev/null
+++ b/drivers/md/dm-bio-record.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_BIO_RECORD_H
+#define DM_BIO_RECORD_H
+
+#include <linux/bio.h>
+
+/*
+ * There are lots of mutable fields in the bio struct that get
+ * changed by the lower levels of the block layer.  Some targets,
+ * such as multipath, may wish to resubmit a bio on error.  The
+ * functions in this file help the target record and restore the
+ * original bio state.
+ */
+
+struct dm_bio_vec_details {
+#if PAGE_SIZE < 65536
+	__u16 bv_len;
+	__u16 bv_offset;
+#else
+	unsigned bv_len;
+	unsigned bv_offset;
+#endif
+};
+
+struct dm_bio_details {
+	sector_t bi_sector;
+	struct block_device *bi_bdev;
+	unsigned int bi_size;
+	unsigned short bi_idx;
+	unsigned long bi_flags;
+	struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES];
+};
+
+static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
+{
+	unsigned i;
+
+	bd->bi_sector = bio->bi_sector;
+	bd->bi_bdev = bio->bi_bdev;
+	bd->bi_size = bio->bi_size;
+	bd->bi_idx = bio->bi_idx;
+	bd->bi_flags = bio->bi_flags;
+
+	for (i = 0; i < bio->bi_vcnt; i++) {
+		bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len;
+		bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset;
+	}
+}
+
+static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio)
+{
+	unsigned i;
+
+	bio->bi_sector = bd->bi_sector;
+	bio->bi_bdev = bd->bi_bdev;
+	bio->bi_size = bd->bi_size;
+	bio->bi_idx = bd->bi_idx;
+	bio->bi_flags = bd->bi_flags;
+
+	for (i = 0; i < bio->bi_vcnt; i++) {
+		bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len;
+		bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset;
+	}
+}
+
+#endif