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203 lines
6.7 KiB
203 lines
6.7 KiB
#ifndef _LINUX_VIRTIO_BLK_H |
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#define _LINUX_VIRTIO_BLK_H |
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/* This header is BSD licensed so anyone can use the definitions to implement |
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* compatible drivers/servers. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of IBM nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. */ |
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#include <linux/types.h> |
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#include <linux/virtio_ids.h> |
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#include <linux/virtio_config.h> |
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#include <linux/virtio_types.h> |
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/* Feature bits */ |
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#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */ |
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#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */ |
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#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */ |
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#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */ |
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#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ |
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#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ |
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#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */ |
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#define VIRTIO_BLK_F_DISCARD 13 /* DISCARD is supported */ |
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#define VIRTIO_BLK_F_WRITE_ZEROES 14 /* WRITE ZEROES is supported */ |
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/* Legacy feature bits */ |
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#ifndef VIRTIO_BLK_NO_LEGACY |
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#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */ |
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#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ |
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#define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */ |
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#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */ |
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#ifndef __KERNEL__ |
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/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */ |
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#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH |
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#endif |
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#endif /* !VIRTIO_BLK_NO_LEGACY */ |
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#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */ |
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struct virtio_blk_config { |
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/* The capacity (in 512-byte sectors). */ |
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__virtio64 capacity; |
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/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */ |
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__virtio32 size_max; |
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/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */ |
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__virtio32 seg_max; |
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/* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */ |
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struct virtio_blk_geometry { |
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__virtio16 cylinders; |
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__u8 heads; |
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__u8 sectors; |
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} geometry; |
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/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ |
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__virtio32 blk_size; |
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/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ |
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/* exponent for physical block per logical block. */ |
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__u8 physical_block_exp; |
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/* alignment offset in logical blocks. */ |
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__u8 alignment_offset; |
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/* minimum I/O size without performance penalty in logical blocks. */ |
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__virtio16 min_io_size; |
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/* optimal sustained I/O size in logical blocks. */ |
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__virtio32 opt_io_size; |
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/* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */ |
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__u8 wce; |
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__u8 unused; |
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/* number of vqs, only available when VIRTIO_BLK_F_MQ is set */ |
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__virtio16 num_queues; |
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/* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */ |
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/* |
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* The maximum discard sectors (in 512-byte sectors) for |
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* one segment. |
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*/ |
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__virtio32 max_discard_sectors; |
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/* |
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* The maximum number of discard segments in a |
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* discard command. |
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*/ |
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__virtio32 max_discard_seg; |
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/* Discard commands must be aligned to this number of sectors. */ |
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__virtio32 discard_sector_alignment; |
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/* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */ |
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/* |
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* The maximum number of write zeroes sectors (in 512-byte sectors) in |
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* one segment. |
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*/ |
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__virtio32 max_write_zeroes_sectors; |
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/* |
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* The maximum number of segments in a write zeroes |
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* command. |
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*/ |
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__virtio32 max_write_zeroes_seg; |
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/* |
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* Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the |
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* deallocation of one or more of the sectors. |
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*/ |
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__u8 write_zeroes_may_unmap; |
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__u8 unused1[3]; |
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} __attribute__((packed)); |
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/* |
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* Command types |
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* |
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* Usage is a bit tricky as some bits are used as flags and some are not. |
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* |
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* Rules: |
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* VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or |
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* VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own |
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* and may not be combined with any of the other flags. |
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*/ |
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/* These two define direction. */ |
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#define VIRTIO_BLK_T_IN 0 |
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#define VIRTIO_BLK_T_OUT 1 |
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#ifndef VIRTIO_BLK_NO_LEGACY |
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/* This bit says it's a scsi command, not an actual read or write. */ |
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#define VIRTIO_BLK_T_SCSI_CMD 2 |
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#endif /* VIRTIO_BLK_NO_LEGACY */ |
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/* Cache flush command */ |
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#define VIRTIO_BLK_T_FLUSH 4 |
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/* Get device ID command */ |
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#define VIRTIO_BLK_T_GET_ID 8 |
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/* Discard command */ |
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#define VIRTIO_BLK_T_DISCARD 11 |
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/* Write zeroes command */ |
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#define VIRTIO_BLK_T_WRITE_ZEROES 13 |
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#ifndef VIRTIO_BLK_NO_LEGACY |
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/* Barrier before this op. */ |
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#define VIRTIO_BLK_T_BARRIER 0x80000000 |
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#endif /* !VIRTIO_BLK_NO_LEGACY */ |
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/* |
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* This comes first in the read scatter-gather list. |
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* For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, |
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* this is the first element of the read scatter-gather list. |
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*/ |
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struct virtio_blk_outhdr { |
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/* VIRTIO_BLK_T* */ |
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__virtio32 type; |
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/* io priority. */ |
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__virtio32 ioprio; |
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/* Sector (ie. 512 byte offset) */ |
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__virtio64 sector; |
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}; |
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/* Unmap this range (only valid for write zeroes command) */ |
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#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001 |
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/* Discard/write zeroes range for each request. */ |
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struct virtio_blk_discard_write_zeroes { |
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/* discard/write zeroes start sector */ |
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__le64 sector; |
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/* number of discard/write zeroes sectors */ |
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__le32 num_sectors; |
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/* flags for this range */ |
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__le32 flags; |
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}; |
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#ifndef VIRTIO_BLK_NO_LEGACY |
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struct virtio_scsi_inhdr { |
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__virtio32 errors; |
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__virtio32 data_len; |
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__virtio32 sense_len; |
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__virtio32 residual; |
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}; |
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#endif /* !VIRTIO_BLK_NO_LEGACY */ |
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/* And this is the final byte of the write scatter-gather list. */ |
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#define VIRTIO_BLK_S_OK 0 |
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#define VIRTIO_BLK_S_IOERR 1 |
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#define VIRTIO_BLK_S_UNSUPP 2 |
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#endif /* _LINUX_VIRTIO_BLK_H */
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