v4.19.13 snapshot.
diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
new file mode 100644
index 0000000..9ebe4d9
--- /dev/null
+++ b/include/uapi/linux/virtio_blk.h
@@ -0,0 +1,149 @@
+#ifndef _LINUX_VIRTIO_BLK_H
+#define _LINUX_VIRTIO_BLK_H
+/* This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE. */
+#include <linux/types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_types.h>
+
+/* Feature bits */
+#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
+#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
+#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */
+#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
+#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
+#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
+#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
+
+/* Legacy feature bits */
+#ifndef VIRTIO_BLK_NO_LEGACY
+#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
+#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
+#define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */
+#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
+#ifndef __KERNEL__
+/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
+#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
+#endif
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+
+#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
+
+struct virtio_blk_config {
+ /* The capacity (in 512-byte sectors). */
+ __u64 capacity;
+ /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
+ __u32 size_max;
+ /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
+ __u32 seg_max;
+ /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
+ struct virtio_blk_geometry {
+ __u16 cylinders;
+ __u8 heads;
+ __u8 sectors;
+ } geometry;
+
+ /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
+ __u32 blk_size;
+
+ /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */
+ /* exponent for physical block per logical block. */
+ __u8 physical_block_exp;
+ /* alignment offset in logical blocks. */
+ __u8 alignment_offset;
+ /* minimum I/O size without performance penalty in logical blocks. */
+ __u16 min_io_size;
+ /* optimal sustained I/O size in logical blocks. */
+ __u32 opt_io_size;
+
+ /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
+ __u8 wce;
+ __u8 unused;
+
+ /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
+ __u16 num_queues;
+} __attribute__((packed));
+
+/*
+ * Command types
+ *
+ * Usage is a bit tricky as some bits are used as flags and some are not.
+ *
+ * Rules:
+ * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
+ * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
+ * and may not be combined with any of the other flags.
+ */
+
+/* These two define direction. */
+#define VIRTIO_BLK_T_IN 0
+#define VIRTIO_BLK_T_OUT 1
+
+#ifndef VIRTIO_BLK_NO_LEGACY
+/* This bit says it's a scsi command, not an actual read or write. */
+#define VIRTIO_BLK_T_SCSI_CMD 2
+#endif /* VIRTIO_BLK_NO_LEGACY */
+
+/* Cache flush command */
+#define VIRTIO_BLK_T_FLUSH 4
+
+/* Get device ID command */
+#define VIRTIO_BLK_T_GET_ID 8
+
+#ifndef VIRTIO_BLK_NO_LEGACY
+/* Barrier before this op. */
+#define VIRTIO_BLK_T_BARRIER 0x80000000
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+
+/*
+ * This comes first in the read scatter-gather list.
+ * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
+ * this is the first element of the read scatter-gather list.
+ */
+struct virtio_blk_outhdr {
+ /* VIRTIO_BLK_T* */
+ __virtio32 type;
+ /* io priority. */
+ __virtio32 ioprio;
+ /* Sector (ie. 512 byte offset) */
+ __virtio64 sector;
+};
+
+#ifndef VIRTIO_BLK_NO_LEGACY
+struct virtio_scsi_inhdr {
+ __virtio32 errors;
+ __virtio32 data_len;
+ __virtio32 sense_len;
+ __virtio32 residual;
+};
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+
+/* And this is the final byte of the write scatter-gather list. */
+#define VIRTIO_BLK_S_OK 0
+#define VIRTIO_BLK_S_IOERR 1
+#define VIRTIO_BLK_S_UNSUPP 2
+#endif /* _LINUX_VIRTIO_BLK_H */