Split scsi/sg.h into a smaller scsi/sg.h which includes a new header:
uapi/scsi/sg.h . Overall expand the twin header files with new
functionality in this patchset and functionality to be added in the
next patchset to implement SG_IOSUBMIT and friends. Adjust format to
modern kernel conventions. Correct and expand some comments.

Signed-off-by: Douglas Gilbert <dgilb...@interlog.com>
---

The new header file: uapi/scsi/sg.h is expected to be in the
kernel's public interface. This takes time (i.e. months or years)
to find its way into glibc and Linux distributions. So the sooner
it is presented and accepted the better.

>From the C perspective, nothing is removed or changed (or shouldn't
be), only additions. This means that the original typedefs stay (but
they are not used in the driver source file: sg.c) since user space
programs may be using them.

 include/scsi/sg.h      | 252 ++-----------------------
 include/uapi/scsi/sg.h | 419 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 430 insertions(+), 241 deletions(-)
 create mode 100644 include/uapi/scsi/sg.h

diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index f91bcca604e4..596f68746f66 100644
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -7,23 +7,23 @@
 /*
  * History:
  *  Started: Aug 9 by Lawrence Foard (entr...@world.std.com), to allow user
- *   process control of SCSI devices.
+ *  process control of SCSI devices.
  *  Development Sponsored by Killy Corp. NY NY
  *
  * Original driver (sg.h):
- *       Copyright (C) 1992 Lawrence Foard
+ *   Copyright (C) 1992 Lawrence Foard
  * Version 2 and 3 extensions to driver:
- *     Copyright (C) 1998 - 2014 Douglas Gilbert
+ *   Copyright (C) 1998 - 2018 Douglas Gilbert
  *
- *  Version: 3.5.36 (20140603)
- *  This version is for 2.6 and 3 series kernels.
+ *  Version: 3.9.01 (20181016)
+ *  This version is for 2.6, 3 and 4 series kernels.
  *
  * Documentation
  * =============
  * A web site for the SG device driver can be found at:
- *     http://sg.danny.cz/sg  [alternatively check the MAINTAINERS file]
+ *   http://sg.danny.cz/sg  [alternatively check the MAINTAINERS file]
  * The documentation for the sg version 3 driver can be found at:
- *     http://sg.danny.cz/sg/p/sg_v3_ho.html
+ *   http://sg.danny.cz/sg/p/sg_v3_ho.html
  * Also see: <kernel_source>/Documentation/scsi/scsi-generic.txt
  *
  * For utility and test programs see: http://sg.danny.cz/sg/sg3_utils.html
@@ -33,242 +33,12 @@
 extern int sg_big_buff; /* for sysctl */
 #endif
 
+#include <uapi/scsi/sg.h>
 
-typedef struct sg_iovec /* same structure as used by readv() Linux system */
-{                       /* call. It defines one scatter-gather element. */
-    void __user *iov_base;      /* Starting address  */
-    size_t iov_len;             /* Length in bytes  */
-} sg_iovec_t;
-
-
-typedef struct sg_io_hdr
-{
-    int interface_id;           /* [i] 'S' for SCSI generic (required) */
-    int dxfer_direction;        /* [i] data transfer direction  */
-    unsigned char cmd_len;      /* [i] SCSI command length */
-    unsigned char mx_sb_len;    /* [i] max length to write to sbp */
-    unsigned short iovec_count; /* [i] 0 implies no scatter gather */
-    unsigned int dxfer_len;     /* [i] byte count of data transfer */
-    void __user *dxferp;       /* [i], [*io] points to data transfer memory
-                                             or scatter gather list */
-    unsigned char __user *cmdp; /* [i], [*i] points to command to perform */
-    void __user *sbp;          /* [i], [*o] points to sense_buffer memory */
-    unsigned int timeout;       /* [i] MAX_UINT->no timeout (unit: millisec) */
-    unsigned int flags;         /* [i] 0 -> default, see SG_FLAG... */
-    int pack_id;                /* [i->o] unused internally (normally) */
-    void __user * usr_ptr;      /* [i->o] unused internally */
-    unsigned char status;       /* [o] scsi status */
-    unsigned char masked_status;/* [o] shifted, masked scsi status */
-    unsigned char msg_status;   /* [o] messaging level data (optional) */
-    unsigned char sb_len_wr;    /* [o] byte count actually written to sbp */
-    unsigned short host_status; /* [o] errors from host adapter */
-    unsigned short driver_status;/* [o] errors from software driver */
-    int resid;                  /* [o] dxfer_len - actual_transferred */
-    unsigned int duration;      /* [o] time taken by cmd (unit: millisec) */
-    unsigned int info;          /* [o] auxiliary information */
-} sg_io_hdr_t;  /* 64 bytes long (on i386) */
-
-#define SG_INTERFACE_ID_ORIG 'S'
-
-/* Use negative values to flag difference from original sg_header structure */
-#define SG_DXFER_NONE (-1)      /* e.g. a SCSI Test Unit Ready command */
-#define SG_DXFER_TO_DEV (-2)    /* e.g. a SCSI WRITE command */
-#define SG_DXFER_FROM_DEV (-3)  /* e.g. a SCSI READ command */
-#define SG_DXFER_TO_FROM_DEV (-4) /* treated like SG_DXFER_FROM_DEV with the
-                                  additional property than during indirect
-                                  IO the user buffer is copied into the
-                                  kernel buffers before the transfer */
-#define SG_DXFER_UNKNOWN (-5)   /* Unknown data direction */
-
-/* following flag values can be "or"-ed together */
-#define SG_FLAG_DIRECT_IO 1     /* default is indirect IO */
-#define SG_FLAG_UNUSED_LUN_INHIBIT 2   /* default is overwrite lun in SCSI */
-                               /* command block (when <= SCSI_2) */
-#define SG_FLAG_MMAP_IO 4       /* request memory mapped IO */
-#define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */
-                               /* user space (debug indirect IO) */
-/* defaults:: for sg driver: Q_AT_HEAD; for block layer: Q_AT_TAIL */
-#define SG_FLAG_Q_AT_TAIL 0x10
-#define SG_FLAG_Q_AT_HEAD 0x20
-
-/* following 'info' values are "or"-ed together */
-#define SG_INFO_OK_MASK 0x1
-#define SG_INFO_OK 0x0          /* no sense, host nor driver "noise" */
-#define SG_INFO_CHECK 0x1       /* something abnormal happened */
-
-#define SG_INFO_DIRECT_IO_MASK 0x6
-#define SG_INFO_INDIRECT_IO 0x0 /* data xfer via kernel buffers (or no xfer) */
-#define SG_INFO_DIRECT_IO 0x2   /* direct IO requested and performed */
-#define SG_INFO_MIXED_IO 0x4    /* part direct, part indirect IO */
-
-
-typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */
-    int host_no;        /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */
-    int channel;
-    int scsi_id;        /* scsi id of target device */
-    int lun;
-    int scsi_type;      /* TYPE_... defined in scsi/scsi.h */
-    short h_cmd_per_lun;/* host (adapter) maximum commands per lun */
-    short d_queue_depth;/* device (or adapter) maximum queue length */
-    int unused[2];      /* probably find a good use, set 0 for now */
-} sg_scsi_id_t; /* 32 bytes long on i386 */
-
-typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
-    char req_state;     /* 0 -> not used, 1 -> written, 2 -> ready to read */
-    char orphan;        /* 0 -> normal request, 1 -> from interruped SG_IO */
-    char sg_io_owned;   /* 0 -> complete with read(), 1 -> owned by SG_IO */
-    char problem;       /* 0 -> no problem detected, 1 -> error to report */
-    int pack_id;        /* pack_id associated with request */
-    void __user *usr_ptr;     /* user provided pointer (in new interface) */
-    unsigned int duration; /* millisecs elapsed since written (req_state==1)
-                             or request duration (req_state==2) */
-    int unused;
-} sg_req_info_t; /* 20 bytes long on i386 */
-
-
-/* IOCTLs: Those ioctls that are relevant to the SG 3.x drivers follow.
- [Those that only apply to the SG 2.x drivers are at the end of the file.]
- (_GET_s yield result via 'int *' 3rd argument unless otherwise indicated) */
-
-#define SG_EMULATED_HOST 0x2203 /* true for emulated host adapter (ATAPI) */
-
-/* Used to configure SCSI command transformation layer for ATAPI devices */
-/* Only supported by the ide-scsi driver */
-#define SG_SET_TRANSFORM 0x2204 /* N.B. 3rd arg is not pointer but value: */
-                     /* 3rd arg = 0 to disable transform, 1 to enable it */
-#define SG_GET_TRANSFORM 0x2205
-
-#define SG_SET_RESERVED_SIZE 0x2275  /* request a new reserved buffer size */
-#define SG_GET_RESERVED_SIZE 0x2272  /* actual size of reserved buffer */
-
-/* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */
-#define SG_GET_SCSI_ID 0x2276   /* Yields fd's bus, chan, dev, lun + type */
-/* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */
-
-/* Override host setting and always DMA using low memory ( <16MB on i386) */
-#define SG_SET_FORCE_LOW_DMA 0x2279  /* 0-> use adapter setting, 1-> force */
-#define SG_GET_LOW_DMA 0x227a   /* 0-> use all ram for dma; 1-> low dma ram */
-
-/* When SG_SET_FORCE_PACK_ID set to 1, pack_id is input to read() which
-   tries to fetch a packet with a matching pack_id, waits, or returns EAGAIN.
-   If pack_id is -1 then read oldest waiting. When ...FORCE_PACK_ID set to 0
-   then pack_id ignored by read() and oldest readable fetched. */
-#define SG_SET_FORCE_PACK_ID 0x227b
-#define SG_GET_PACK_ID 0x227c /* Yields oldest readable pack_id (or -1) */
-
-#define SG_GET_NUM_WAITING 0x227d /* Number of commands awaiting read() */
-
-/* Yields max scatter gather tablesize allowed by current host adapter */
-#define SG_GET_SG_TABLESIZE 0x227F  /* 0 implies can't do scatter gather */
-
-#define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */
-
-/* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */
-#define SG_SCSI_RESET 0x2284
-/* Associated values that can be given to SG_SCSI_RESET follow.
- * SG_SCSI_RESET_NO_ESCALATE may be OR-ed to the _DEVICE, _TARGET, _BUS
- * or _HOST reset value so only that action is attempted. */
-#define                SG_SCSI_RESET_NOTHING   0
-#define                SG_SCSI_RESET_DEVICE    1
-#define                SG_SCSI_RESET_BUS       2
-#define                SG_SCSI_RESET_HOST      3
-#define                SG_SCSI_RESET_TARGET    4
-#define                SG_SCSI_RESET_NO_ESCALATE       0x100
-
-/* synchronous SCSI command ioctl, (only in version 3 interface) */
-#define SG_IO 0x2285   /* similar effect as write() followed by read() */
-
-#define SG_GET_REQUEST_TABLE 0x2286   /* yields table of active requests */
-
-/* How to treat EINTR during SG_IO ioctl(), only in SG 3.x series */
-#define SG_SET_KEEP_ORPHAN 0x2287 /* 1 -> hold for read(), 0 -> drop (def) */
-#define SG_GET_KEEP_ORPHAN 0x2288
-
-/* yields scsi midlevel's access_count for this SCSI device */
-#define SG_GET_ACCESS_COUNT 0x2289  
-
-
-#define SG_SCATTER_SZ (8 * 4096)
-/* Largest size (in bytes) a single scatter-gather list element can have.
-   The value used by the driver is 'max(SG_SCATTER_SZ, PAGE_SIZE)'.
-   This value should be a power of 2 (and may be rounded up internally).
-   If scatter-gather is not supported by adapter then this value is the
-   largest data block that can be read/written by a single scsi command. */
-
-#define SG_DEFAULT_RETRIES 0
-
-/* Defaults, commented if they differ from original sg driver */
-#define SG_DEF_FORCE_PACK_ID 0
-#define SG_DEF_KEEP_ORPHAN 0
-#define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */
-
-/* maximum outstanding requests, write() yields EDOM if exceeded */
-#define SG_MAX_QUEUE 16
-
-#define SG_BIG_BUFF SG_DEF_RESERVED_SIZE    /* for backward compatibility */
-
-/* Alternate style type names, "..._t" variants preferred */
-typedef struct sg_io_hdr Sg_io_hdr;
-typedef struct sg_io_vec Sg_io_vec;
-typedef struct sg_scsi_id Sg_scsi_id;
-typedef struct sg_req_info Sg_req_info;
-
-
-/* vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv */
-/*   The older SG interface based on the 'sg_header' structure follows.   */
-/* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */
-
-#define SG_MAX_SENSE 16   /* this only applies to the sg_header interface */
-
-struct sg_header
-{
-    int pack_len;    /* [o] reply_len (ie useless), ignored as input */
-    int reply_len;   /* [i] max length of expected reply (inc. sg_header) */
-    int pack_id;     /* [io] id number of packet (use ints >= 0) */
-    int result;      /* [o] 0==ok, else (+ve) Unix errno (best ignored) */
-    unsigned int twelve_byte:1;
-       /* [i] Force 12 byte command length for group 6 & 7 commands  */
-    unsigned int target_status:5;   /* [o] scsi status from target */
-    unsigned int host_status:8;     /* [o] host status (see "DID" codes) */
-    unsigned int driver_status:8;   /* [o] driver status+suggestion */
-    unsigned int other_flags:10;    /* unused */
-    unsigned char sense_buffer[SG_MAX_SENSE]; /* [o] Output in 3 cases:
-          when target_status is CHECK_CONDITION or
-          when target_status is COMMAND_TERMINATED or
-          when (driver_status & DRIVER_SENSE) is true. */
-};      /* This structure is 36 bytes long on i386 */
-
-
-/* IOCTLs: The following are not required (or ignored) when the sg_io_hdr_t
-          interface is used. They are kept for backward compatibility with
-          the original and version 2 drivers. */
-
-#define SG_SET_TIMEOUT 0x2201  /* unit: jiffies (10ms on i386) */
-#define SG_GET_TIMEOUT 0x2202  /* yield timeout as _return_ value */
-
-/* Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q.
-   Each time a sg_io_hdr_t object is seen on this file descriptor, this
-   command queuing flag is set on (overriding the previous setting). */
-#define SG_GET_COMMAND_Q 0x2270   /* Yields 0 (queuing off) or 1 (on) */
-#define SG_SET_COMMAND_Q 0x2271   /* Change queuing state with 0 or 1 */
-
-/* Turn on/off error sense trace (1 and 0 respectively, default is off).
-   Try using: "# cat /proc/scsi/sg/debug" instead in the v3 driver */
-#define SG_SET_DEBUG 0x227e    /* 0 -> turn off debug */
-
-#define SG_NEXT_CMD_LEN 0x2283  /* override SCSI command length with given
-                  number on the next write() on this file descriptor */
-
-
-/* Defaults, commented if they differ from original sg driver */
 #ifdef __KERNEL__
-#define SG_DEFAULT_TIMEOUT_USER        (60*USER_HZ) /* HZ == 'jiffies in 1 
second' */
-#else
-#define SG_DEFAULT_TIMEOUT     (60*HZ)      /* HZ == 'jiffies in 1 second' */
+#define SG_DEFAULT_TIMEOUT_USER (60*USER_HZ) /* HZ == 'jiffies in 1 second' */
 #endif
 
-#define SG_DEF_COMMAND_Q 0     /* command queuing is always on when
-                                 the new interface is used */
-#define SG_DEF_UNDERRUN_FLAG 0
+#undef SG_DEFAULT_TIMEOUT      /* cause define in sg.c */
 
-#endif
+#endif /* end of ifndef _SCSI_GENERIC_H guard */
diff --git a/include/uapi/scsi/sg.h b/include/uapi/scsi/sg.h
new file mode 100644
index 000000000000..37588e1c4e3a
--- /dev/null
+++ b/include/uapi/scsi/sg.h
@@ -0,0 +1,419 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _UAPI_SCSI_SG_H
+#define _UAPI_SCSI_SG_H
+
+/*
+ * Want to block the original sg.h header from also being included. That
+ * causes lots of multiple definition errors. This will only work if this
+ * header is included _before_ the original sg.h header .
+ */
+#define _SCSI_GENERIC_H                /* original kernel header guard */
+#define _SCSI_SG_H             /* glibc header guard */
+
+/*
+ * Other UAPI headers include linux/compiler.h to resolve "__" types but that
+ * doesn't always work, perhaps in the future. Fall back to linux/types.h .
+ */
+/* #include <linux/compiler.h> */
+#include <linux/types.h>
+#include <linux/major.h>
+
+/* Still problems with __user so define to nothing */
+#define __user
+
+#include <linux/bsg.h>
+
+/*
+ * History:
+ *  Started: Aug 9 by Lawrence Foard (entr...@world.std.com), to allow user
+ *  process control of SCSI devices.
+ *  Development Sponsored by Killy Corp. NY NY
+ *
+ * Original driver (sg.h):
+ *   Copyright (C) 1992 Lawrence Foard
+ * Version 2 and 3 extensions to driver:
+ *   Copyright (C) 1998 - 2018 Douglas Gilbert
+ *
+ *  Version: 3.9.01 (20181021)
+ *  This version is for Linux 2.6, 3 and 4 series kernels.
+ *
+ * Documentation
+ * =============
+ * A web site for the SG device driver can be found at:
+ *   http://sg.danny.cz/sg  [alternatively check the MAINTAINERS file]
+ * The documentation for the sg version 3 driver can be found at:
+ *   http://sg.danny.cz/sg/p/sg_v3_ho.html
+ * Also see: <kernel_source>/Documentation/scsi/scsi-generic.txt
+ *
+ * For utility and test programs see: http://sg.danny.cz/sg/sg3_utils.html
+ */
+
+
+/*
+ * Same structure as used by readv() call. It defines one scatter-gather
+ * element. "Scatter-gather" is abbreviated to "sgat" in thsi driver to
+ * avoid confusion with this driver's name.
+ */
+typedef struct sg_iovec        {
+       void __user *iov_base;  /* Starting address (of a byte) */
+       size_t iov_len;         /* Length in bytes */
+} sg_iovec_t;
+
+
+typedef struct sg_io_hdr {
+       int interface_id;       /* [i] 'S' for SCSI generic (required) */
+       int dxfer_direction;    /* [i] data transfer direction  */
+       unsigned char cmd_len;  /* [i] SCSI command length */
+       unsigned char mx_sb_len;/* [i] max length to write to sbp */
+       unsigned short iovec_count;     /* [i] 0 implies no scatter gather */
+       unsigned int dxfer_len; /* [i] byte count of data transfer */
+       /* points to data transfer memory or scatter gather list */
+       void __user *dxferp;    /* [i], [*io] */
+       unsigned char __user *cmdp;/* [i], [*i] points to command to perform */
+       void __user *sbp;       /* [i], [*o] points to sense_buffer memory */
+       unsigned int timeout;   /* [i] MAX_UINT->no timeout (unit: millisec) */
+       unsigned int flags;     /* [i] 0 -> default, see SG_FLAG... */
+       int pack_id;            /* [i->o] unused internally (normally) */
+       void __user *usr_ptr;   /* [i->o] unused internally */
+       unsigned char status;   /* [o] scsi status */
+       unsigned char masked_status;/* [o] shifted, masked scsi status */
+       unsigned char msg_status;/* [o] messaging level data (optional) */
+       unsigned char sb_len_wr; /* [o] byte count actually written to sbp */
+       unsigned short host_status; /* [o] errors from host adapter */
+       unsigned short driver_status;/* [o] errors from software driver */
+       int resid;              /* [o] dxfer_len - actual_transferred */
+       /* unit may be nanoseconds after SG_SET_GET_EXTENDED ioctl use */
+       unsigned int duration;  /* [o] time taken by cmd (unit: millisec) */
+       unsigned int info;      /* [o] auxiliary information */
+} sg_io_hdr_t;
+
+#define SG_INTERFACE_ID_ORIG 'S'
+
+/* Use negative values to flag difference from original sg_header structure */
+#define SG_DXFER_NONE (-1)     /* e.g. a SCSI Test Unit Ready command */
+#define SG_DXFER_TO_DEV (-2)   /* data-out buffer e.g. SCSI WRITE command */
+#define SG_DXFER_FROM_DEV (-3) /* data-in buffer e.g. SCSI READ command */
+/*
+ * treated like SG_DXFER_FROM_DEV with the additional property than during
+ * indirect IO the user buffer is copied into the kernel buffers _before_
+ * the transfer from the device takes place. Useful if short DMA transfers
+ * (less than requested) are not reported (e.g. resid always 0).
+ */
+#define SG_DXFER_TO_FROM_DEV (-4)
+#define SG_DXFER_UNKNOWN (-5)  /* Unknown data direction, do not use */
+
+/* following flag values can be OR-ed together */
+#define SG_FLAG_DIRECT_IO 1    /* default is indirect IO */
+#define SG_FLAG_UNUSED_LUN_INHIBIT 2   /* default is overwrite lun in SCSI */
+                               /* command block (when <= SCSI_2) */
+#define SG_FLAG_MMAP_IO 4      /* request memory mapped IO */
+/* no transfer of kernel buffers to/from user space; to debug indirect IO */
+#define SG_FLAG_NO_DXFER 0x10000
+/* defaults: for sg driver: Q_AT_HEAD; for block layer: Q_AT_TAIL */
+#define SG_FLAG_Q_AT_TAIL 0x10
+#define SG_FLAG_Q_AT_HEAD 0x20
+
+/*
+ * Flags used by ioctl(SG_IOSUBMIT) [abbrev: SG_IOS] and ioctl(SG_IORECEIVE)
+ * [abbrev: SG_IOR] OR-ed into sg_io_v4::flags, also with ioctl(SG_IO) when
+ * sg_io_v4::guard is 'Q' in which case SGV4_FLAG_SYNC is implicitly set.
+ * These flags apply for SG_IOS unless otherwise noted. May be OR-ed together.
+ */
+#define SGV4_FLAG_DIRECT_IO SG_FLAG_DIRECT_IO
+#define SGV4_FLAG_MMAP_IO SG_FLAG_MMAP_IO
+#define SGV4_FLAG_SYNC 0x8     /* similar to ioctl(SG_IO) */
+#define SGV4_FLAG_Q_AT_TAIL SG_FLAG_Q_AT_TAIL
+#define SGV4_FLAG_Q_AT_HEAD SG_FLAG_Q_AT_HEAD
+/* Following 2 flags for request::tag (type: int) manipulations */
+#define SGV4_NO_TAG_REQUIRED 0x100     /* default: SG_IOS yields tag */
+#define SGV4_USE_GIVEN_TAG 0x200       /* SG_IOR selector else ignored */
+#define SGV4_FLAG_IMMED 0x400  /* for polling with SG_IOR else ignored */
+#define SGV4_FLAG_ASYNC 0x800  /* make sync ioctl (e.g. SG_IO) async */
+#define SGV4_FLAG_DEV_SCOPE 0x1000 /* permit SG_IOABORT to have wider scope */
+#define SGV4_FLAG_NO_DXFER SG_FLAG_NO_DXFER
+
+/* following 'info' values are OR-ed together */
+#define SG_INFO_OK_MASK 0x1
+#define SG_INFO_OK 0x0         /* no sense, host nor driver "noise" */
+#define SG_INFO_CHECK 0x1      /* something abnormal happened */
+
+#define SG_INFO_DIRECT_IO_MASK 0x6
+#define SG_INFO_INDIRECT_IO 0x0        /* data xfer via kernel buffers (or no 
xfer) */
+#define SG_INFO_DIRECT_IO 0x2  /* direct IO requested and performed */
+#define SG_INFO_MIXED_IO 0x4   /* part direct, part indirect IO */
+#define SG_INFO_DEVICE_DETACHING 0x8   /* completed successfully but ... */
+
+
+typedef struct sg_scsi_id {    /* used by SG_GET_SCSI_ID ioctl() */
+       int host_no;    /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */
+       int channel;
+       int scsi_id;    /* scsi id of target device */
+       int lun;
+       int scsi_type;  /* TYPE_... defined in scsi/scsi.h */
+       short h_cmd_per_lun;/* host (adapter) maximum commands per lun */
+       short d_queue_depth;/* device (or adapter) maximum queue length */
+       int unused[2];  /* probably find a good use, set 0 for now */
+} sg_scsi_id_t;
+
+typedef struct sg_req_info {   /* used by SG_GET_REQUEST_TABLE ioctl() */
+       char req_state; /* 0 -> not used, 1 -> written, 2 -> ready to read */
+       char orphan;    /* 0 -> normal request, 1 -> from interruped SG_IO */
+       char sg_io_owned;/* 0 -> complete with read(), 1 -> owned by SG_IO */
+       char problem;   /* 0 -> no problem detected, 1 -> error to report */
+       int pack_id;    /* pack_id associated with request */
+       void __user *usr_ptr;   /* user provided pointer (in new interface) */
+       /*
+        * millisecs elapsed since the command started (req_state==1) or
+        * command duration (req_state==2). May be in nanoseconds after
+        * the SG_SET_GET_EXTENDED ioctl.
+        */
+       unsigned int duration;
+       int unused;
+} sg_req_info_t;
+
+/*
+ * The following defines may help when using struct sg_extended_info which
+ * is abbreviated to "SEI". A following "M" (i.e. "_SEIM_") indicates a
+ * mask. Most mask values correspond to a integer (usually a __u32) apart
+ * from SG_SEIM_CTL_FLAGS which is for a collection of boolean values
+ * packed into an integer. The mask values for those booleans start with
+ * "SG_CTL_FLAGM_". The scope of these settings, like most other ioctls,
+ * is usually that of the file descriptor the ioctl is executed on. Masks
+ * marked with "rd" are read-only, attempts to write to them are ignored.
+ */
+#define SG_SEIM_RESERVED_SIZE  0x1     /* reserved_sz field valid */
+#define SG_SEIM_RQ_REM_THRESH  0x2     /* rq_rem_sgat_thresh field valid */
+#define SG_SEIM_TOT_FD_THRESH  0x4     /* tot_fd_thresh field valid */
+#define SG_SEIM_CTL_FLAGS      0x8     /* ctl_flags_mask bits in ctl_flags */
+#define SG_SEIM_MINOR_INDEX    0x10    /* sg device minor index number */
+#define SG_SEIM_ALL_BITS       0x1f    /* should be OR of previous items */
+
+#define SG_CTL_FLAGM_TIME_IN_NS        0x1     /* time: nanosecs (def: 
millisecs) */
+#define SG_CTL_FLAGM_TAG_FOR_PACK_ID   0x2
+#define SG_CTL_FLAGM_OTHER_OPENS       0x4 /* rd: other sg fd_s on this dev */
+#define SG_CTL_FLAGM_ORPHANS   0x8     /* rd: orphaned requests on this fd */
+
+/*
+ * A pointer to the following structure is passed as the third argument to 
+ * ioctl(SG_SET_GET_EXTENDED). Each bit in the *_wr_mask fields causes the
+ * corresponding integer (e.g. reserved_sz) or bit (e.g. the
+ * SG_CTL_FLAG_TIME_IN_NS bit in ctl_flags) to be read from the user space
+ * and modify the driver. Each bit in the *_rd_mask fields causes the
+ * corresponding integer or bit to be fetched from the driver and written
+ * back to the user space. If the same bit is set in both the *_wr_mask and
+ * corresponding *_rd_mask fields, then the write action takes place before
+ * the read action and no other operation will split the two. This structure
+ * is padded to 64 bytes to allow for new values to be added in the future.
+ */
+struct sg_extended_info {
+       __u32   valid_wr_mask;  /* OR-ed SG_SEIM_* values */
+       __u32   valid_rd_mask;  /* OR-ed SG_SEIM_* values */
+       __u32   reserved_sz;    /* data/sgl size of pre-allocated request */
+       __u32   rq_rem_sgat_thresh;/* request re-use: clear data/sgat if > */
+       __u32   tot_fd_thresh;  /* total data/sgat for this fd, 0: no limit */
+       __u32   ctl_flags_wr_mask;      /* OR-ed SG_CTL_FLAGM_* values */
+       __u32   ctl_flags_rd_mask;      /* OR-ed SG_CTL_FLAGM_* values */
+       __u32   ctl_flags;      /* bit values OR-ed, see SG_CTL_FLAGM_* */
+       __u32   minor_index;    /* rd: kernel's sg device minor number */
+       __u8    pad_to_64[28];  /* pad so struct is 64 bytes long */
+};
+
+/*
+ * IOCTLs: Those ioctls that are relevant to the SG 3.x drivers follow.
+ * [Those that only apply to the SG 2.x drivers are at the end of the file.]
+ * (_GET_s yield result via 'int *' 3rd argument unless otherwise indicated)
+ */
+
+#define SG_EMULATED_HOST 0x2203        /* true for emulated host adapter 
(ATAPI) */
+
+/*
+ * Used to configure SCSI command transformation layer for ATAPI devices.
+ * Only supported by the ide-scsi driver. 20181014 No longer supported, this
+ * driver passes them to the mid-level which returns a EINVAL (22) errno.
+ *
+ * Original note: N.B. 3rd arg is not pointer but value: 3rd arg = 0 to
+ * disable transform, 1 to enable it
+ */
+#define SG_SET_TRANSFORM 0x2204
+#define SG_GET_TRANSFORM 0x2205
+
+#define SG_SET_RESERVED_SIZE 0x2275  /* request new reserved buffer size */
+#define SG_GET_RESERVED_SIZE 0x2272  /* actual size of reserved buffer */
+
+/*
+ * Historically the scsi/sg driver has used 0x22 as it ioctl base number.
+ * Add a define for that value and use it for several new ioctls added in
+ * version 3.9.01 sg driver.
+ */
+#define SG_IOCTL_MAGIC_NUM 0x22
+
+#define SG_SET_GET_EXTENDED _IOWR(SG_IOCTL_MAGIC_NUM, 0x51,    \
+                                 struct sg_extended_info)
+
+/* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */
+#define SG_GET_SCSI_ID 0x2276   /* Yields fd's bus, chan, dev, lun + type */
+/* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */
+
+/* Override host setting and always DMA using low memory ( <16MB on i386) */
+#define SG_SET_FORCE_LOW_DMA 0x2279  /* 0-> use adapter setting, 1-> force */
+#define SG_GET_LOW_DMA 0x227a  /* 0-> use all ram for dma; 1-> low dma ram */
+
+/*
+ * When SG_SET_FORCE_PACK_ID set to 1, pack_id is input to read() which
+ * tries to fetch a packet with a matching pack_id, waits, or returns EAGAIN.
+ * If pack_id is -1 then read oldest waiting. When ...FORCE_PACK_ID set to 0
+ * then pack_id ignored by read() and oldest readable fetched.
+ */
+#define SG_SET_FORCE_PACK_ID 0x227b
+#define SG_GET_PACK_ID 0x227c  /* Yields oldest readable pack_id (or -1) */
+
+#define SG_GET_NUM_WAITING 0x227d /* Number of commands awaiting read() */
+
+/* Yields max scatter gather tablesize allowed by current host adapter */
+#define SG_GET_SG_TABLESIZE 0x227F  /* 0 implies can't do scatter gather */
+
+#define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */
+
+/* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */
+#define SG_SCSI_RESET 0x2284
+/*
+ * Associated values that can be given to SG_SCSI_RESET follow.
+ * SG_SCSI_RESET_NO_ESCALATE may be OR-ed to the _DEVICE, _TARGET, _BUS
+ * or _HOST reset value so only that action is attempted.
+ */
+#define                SG_SCSI_RESET_NOTHING   0
+#define                SG_SCSI_RESET_DEVICE    1
+#define                SG_SCSI_RESET_BUS       2
+#define                SG_SCSI_RESET_HOST      3
+#define                SG_SCSI_RESET_TARGET    4
+#define                SG_SCSI_RESET_NO_ESCALATE       0x100
+
+/* synchronous SCSI command ioctl, (only in version 3 interface) */
+#define SG_IO 0x2285   /* similar effect as write() followed by read() */
+
+#define SG_GET_REQUEST_TABLE 0x2286    /* yields table of active requests */
+
+/* How to treat EINTR during SG_IO ioctl(), only in SG 3.x series */
+#define SG_SET_KEEP_ORPHAN 0x2287 /* 1 -> hold for read(), 0 -> drop (def) */
+#define SG_GET_KEEP_ORPHAN 0x2288
+
+/*
+ * Yields scsi midlevel's access_count for this SCSI device. 20181014 No
+ * longer available, always yields 1.
+ */
+#define SG_GET_ACCESS_COUNT 0x2289
+
+
+/*
+ * Largest size (in bytes) a single scatter-gather list element can have.
+ * The value used by the driver is 'max(SG_SCATTER_SZ, PAGE_SIZE)'.
+ * This value should be a power of 2 (and may be rounded up internally).
+ * If scatter-gather is not supported by adapter then this value is the
+ * largest data block that can be read/written by a single scsi command.
+ */
+#define SG_SCATTER_SZ (8 * 4096)
+
+#define SG_DEFAULT_RETRIES 0
+
+/* Defaults, commented if they differ from original sg driver */
+#define SG_DEF_FORCE_PACK_ID 0
+#define SG_DEF_KEEP_ORPHAN 0
+#define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */
+
+/*
+ * Maximum outstanding requests (i.e write()s without corresponding read()s)
+ * yields EDOM from write() if exceeded. This limit only applies prior to
+ * version 3.9 . It is still used as a maximum number of sg_req_info objects
+ * that are returned from the SG_GET_REQUEST_TABLE ioctl.
+ */
+#define SG_MAX_QUEUE 16
+
+#define SG_BIG_BUFF SG_DEF_RESERVED_SIZE    /* for backward compatibility */
+
+/*
+ * Alternate style type names, "..._t" variants (as found in the
+ * 'typedef struct * {};' definitions above) are preferred to these:
+ */
+typedef struct sg_io_hdr Sg_io_hdr;
+typedef struct sg_io_vec Sg_io_vec;
+typedef struct sg_scsi_id Sg_scsi_id;
+typedef struct sg_req_info Sg_req_info;
+
+
+/* vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv */
+/*   The older SG interface based on the 'sg_header' structure follows.   */
+/* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */
+
+#define SG_MAX_SENSE 16        /* this only applies to the sg_header interface 
*/
+
+struct sg_header {
+       int pack_len;   /* [o] reply_len (ie useless), ignored as input */
+       int reply_len;  /* [i] max length of expected reply (inc. sg_header) */
+       int pack_id;    /* [io] id number of packet (use ints >= 0) */
+       int result;     /* [o] 0==ok, else (+ve) Unix errno (best ignored) */
+       unsigned int twelve_byte:1;
+           /* [i] Force 12 byte command length for group 6 & 7 commands  */
+       unsigned int target_status:5;   /* [o] scsi status from target */
+       unsigned int host_status:8;     /* [o] host status (see "DID" codes) */
+       unsigned int driver_status:8;   /* [o] driver status+suggestion */
+       unsigned int other_flags:10;    /* unused */
+       unsigned char sense_buffer[SG_MAX_SENSE];
+       /*
+        * [o] Output in 3 cases:
+        *      when target_status is CHECK_CONDITION or
+        *      when target_status is COMMAND_TERMINATED or
+        *      when (driver_status & DRIVER_SENSE) is true.
+        */
+};
+
+/*
+ * IOCTLs: The following are not required (or ignored) when the sg_io_hdr_t
+ *  interface is used. They are kept for backward compatibility with
+ * the original and version 2 drivers.
+ */
+
+#define SG_SET_TIMEOUT 0x2201  /* unit: jiffies (10ms on i386) */
+#define SG_GET_TIMEOUT 0x2202  /* yield timeout as _return_ value */
+
+/*
+ * Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q.
+ * Each time a sg_io_hdr_t object is seen on this file descriptor, this
+ * command queuing flag is set on (overriding the previous setting).
+ */
+#define SG_GET_COMMAND_Q 0x2270   /* Yields 0 (queuing off) or 1 (on) */
+#define SG_SET_COMMAND_Q 0x2271   /* Change queuing state with 0 or 1 */
+
+/*
+ * Turn on/off error sense trace (1 and 0 respectively, default is off).
+ * Try using: "# cat /proc/scsi/sg/debug" instead in the v3 driver
+ */
+#define SG_SET_DEBUG 0x227e    /* 0 -> turn off debug */
+
+/*
+ * override SCSI command length with given number on the next write() on
+ * this file descriptor
+ */
+#define SG_NEXT_CMD_LEN 0x2283
+
+/*
+ * New ioctls to replace async write()/read() interface. Present in version
+ * 4 and later of the sg driver [>20181014]. These two ioctls accept both
+ * the sg_v3 interface (structure defined above) and the sg_v4 interface
+ * (structure defined in <include/uapi/linux/bsg.h> ). Following "read" and
+ * "write" terms are from the driver's POV, the _IO macros from users' POV.
+ */
+/* via pointer reads sg v3 or v4 object, optionally writes tag, so _IOWR */
+#define SG_IOSUBMIT _IOWR(SG_IOCTL_MAGIC_NUM, 0x41, struct sg_io_v4)
+/* via pointer optionally reads tag, writes sg v3 or v4 object, so _IOWR */
+#define SG_IORECEIVE _IOWR(SG_IOCTL_MAGIC_NUM, 0x42, struct sg_io_v4)
+/* via pointer reads v4 object (including tag), writes nothing, so _IOW */
+#define SG_IOABORT _IOW(SG_IOCTL_MAGIC_NUM, 0x43, struct sg_io_v4)
+
+/* command queuing is always on when the new interface is used */
+#define SG_DEF_COMMAND_Q 0
+
+#define SG_DEF_UNDERRUN_FLAG 0
+
+#define SG_DEFAULT_TIMEOUT     (60*HZ) /* HZ == 'jiffies in 1 second' */
+
+#endif
-- 
2.17.1

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