cregit-Linux how code gets into the kernel

Release 4.12 include/uapi/linux/virtio_blk.h

#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 */

Overall Contributors

PersonTokensPropCommitsCommitProp
Rusty Russell14052.43%627.27%
Christoph Hellwig2710.11%29.09%
Christian Bornträger217.87%418.18%
Ryan Harper197.12%14.55%
Michael S. Tsirkin176.37%418.18%
Hannes Reinecke155.62%14.55%
john cooper103.75%14.55%
Ming Lei93.37%14.55%
Paolo Bonzini62.25%14.55%
Jaswinder Singh Rajput31.12%14.55%
Total267100.00%22100.00%
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