include/linux/virtio_blk.h

   1 #ifndef _LINUX_VIRTIO_BLK_H
   2 #define _LINUX_VIRTIO_BLK_H
   3 #include <linux/virtio_config.h>
   4
   5 /* The ID for virtio_block */
   6 #define VIRTIO_ID_BLOCK 2
   7
   8 /* Feature bits */
   9 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  10 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
  11 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
  12 #define VIRTIO_BLK_F_GEOMETRY   4       /* Legacy geometry available  */
  13
  14 struct virtio_blk_config
  15 {
  16         /* The capacity (in 512-byte sectors). */
  17         __le64 capacity;
  18         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  19         __le32 size_max;
  20         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  21         __le32 seg_max;
  22         /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
  23         struct virtio_blk_geometry {
  24                 __le16 cylinders;
  25                 __u8 heads;
  26                 __u8 sectors;
  27         } geometry;
  28 } __attribute__((packed));
  29
  30 /* These two define direction. */
  31 #define VIRTIO_BLK_T_IN         0
  32 #define VIRTIO_BLK_T_OUT        1
  33
  34 /* This bit says it's a scsi command, not an actual read or write. */
  35 #define VIRTIO_BLK_T_SCSI_CMD   2
  36
  37 /* Barrier before this op. */
  38 #define VIRTIO_BLK_T_BARRIER    0x80000000
  39
  40 /* This is the first element of the read scatter-gather list. */
  41 struct virtio_blk_outhdr
  42 {
  43         /* VIRTIO_BLK_T* */
  44         __u32 type;
  45         /* io priority. */
  46         __u32 ioprio;
  47         /* Sector (ie. 512 byte offset) */
  48         __u64 sector;
  49 };
  50
  51 /* And this is the final byte of the write scatter-gather list. */
  52 #define VIRTIO_BLK_S_OK         0
  53 #define VIRTIO_BLK_S_IOERR      1
  54 #define VIRTIO_BLK_S_UNSUPP     2
  55 #endif /* _LINUX_VIRTIO_BLK_H */