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
  13 struct virtio_blk_config
  14 {
  15         /* The capacity (in 512-byte sectors). */
  16         __le64 capacity;
  17         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  18         __le32 size_max;
  19         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  20         __le32 seg_max;
  21 } __attribute__((packed));
  22
  23 /* These two define direction. */
  24 #define VIRTIO_BLK_T_IN         0
  25 #define VIRTIO_BLK_T_OUT        1
  26
  27 /* This bit says it's a scsi command, not an actual read or write. */
  28 #define VIRTIO_BLK_T_SCSI_CMD   2
  29
  30 /* Barrier before this op. */
  31 #define VIRTIO_BLK_T_BARRIER    0x80000000
  32
  33 /* This is the first element of the read scatter-gather list. */
  34 struct virtio_blk_outhdr
  35 {
  36         /* VIRTIO_BLK_T* */
  37         __u32 type;
  38         /* io priority. */
  39         __u32 ioprio;
  40         /* Sector (ie. 512 byte offset) */
  41         __u64 sector;
  42 };
  43
  44 #define VIRTIO_BLK_S_OK         0
  45 #define VIRTIO_BLK_S_IOERR      1
  46 #define VIRTIO_BLK_S_UNSUPP     2
  47
  48 /* This is the first element of the write scatter-gather list */
  49 struct virtio_blk_inhdr
  50 {
  51         unsigned char status;
  52 };
  53 #endif /* _LINUX_VIRTIO_BLK_H */