patch-2.3.43 linux/include/scsi/sg.h

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diff -u --recursive --new-file v2.3.42/linux/include/scsi/sg.h linux/include/scsi/sg.h
@@ -3,25 +3,25 @@
 
 /*
    History:
-    Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user 
-     process control of SCSI devices. 
+    Started: Aug 9 by Lawrence Foard (entropy@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
-2.x extensions to driver:
+Version 2 and 3 extensions to driver:
 *       Copyright (C) 1998, 1999 Douglas Gilbert
 
+    Version: 3.1.10 (20000123)
+    This version is for 2.3/2.4 series kernels.
 
-    Version: 2.3.35 (990708)
-    This version for 2.3 series kernels. It only differs from sg version
-    2.1.35 used in the 2.2 series kernels by changes to wait_queue. This
-    in an internal kernel interface and should not effect users.
-        D. P. Gilbert (dgilbert@interlog.com, dougg@triode.net.au)
-
-    Changes since 2.1.34 (990603)
+    Changes since 2.1.34 (990603) and 2.3.35 (990708)
+	- add new interface structure: sg_io_hdr_t
+	  - supports larger sense buffer, DMA residual count + direct IO
+	- add SG_IO ioctl (combines function of write() + read() )
+	- remove SG_SET_MERGE_FD, UNDERRUN_FLAG + _GET_ ioctls + logic
+	- add proc_fs support in /proc/scsi/sg/ directory
         - add queuing info into struct sg_scsi_id
-        - block negative timeout values
-        - add back write() wait on previous read() when no cmd queuing
+	- def_reserved_size can be given at driver or module load time
     Changes since 2.1.33 (990521)
         - implement SG_SET_RESERVED_SIZE and associated memory re-org.
         - add SG_NEXT_CMD_LEN to override SCSI command lengths
@@ -34,117 +34,135 @@
         - clean up logging of pointers to use %p (for 64 bit architectures)
         - rework usage of get_user/copy_to_user family of kernel calls
         - "disown" scsi_command blocks before releasing them
-    Changes since 2.1.30 (990320)
-        - memory tweaks: change flags on kmalloc (GFP_KERNEL to GFP_ATOMIC)
-        -                increase max allowable mid-level pool usage
-
-
-    New features and changes:
-        - per file descriptor (fd) write-read sequencing and command queues.
-        - command queuing supported (SG_MAX_QUEUE is maximum per fd).
-        - scatter-gather supported (allowing potentially megabyte transfers).
-        - the SCSI target, host and driver status are returned
-          in unused fields of sg_header (maintaining its original size).
-        - asynchronous notification support added (SIGPOLL, SIGIO) for
-          read()s (write()s should never block).
-        - pack_id logic added so read() can wait for a specific pack_id. 
-        - uses memory > ISA_DMA_THRESHOLD if adapter allows it (e.g. a
-          pci scsi adapter).
-        - this driver no longer uses a single SG_BIG_BUFF sized buffer
-          obtained at driver/module init time. Rather it tries to obtain a 
-          SG_DEF_RESERVED_SIZE buffer when a fd is open()ed and frees it
-          at the corresponding release() (ie per fd). Actually the "buffer"
-          may be a collection of buffers if scatter-gather is being used.
-        - add SG_SET_RESERVED_SIZE ioctl allowing the user to request a
-          large buffer for duration of current file descriptor's lifetime.
-        - SG_GET_RESERVED_SIZE ioctl can be used to find out how much
-          actually has been reserved.
-        - add SG_NEXT_CMD_LEN ioctl to override SCSI command length on
-          the next write() to this file descriptor.
-        - SG_GET_RESERVED_SIZE's presence as a symbol can be used for
-          compile time identification of the version 2 sg driver.
-          However, it is recommended that run time identification based on
-          calling the ioctl of the same name is a more flexible and
-          safer approach.
-        - adds several ioctl calls, see ioctl section below.
- 
- Good documentation on the original "sg" device interface and usage can be
- found in the Linux HOWTO document: "SCSI Programming HOWTO" (version 0.5)
- by Heiko Eissfeldt; last updated 7 May 1996. Here is a quick summary of
- sg basics:
- An SG device is accessed by writing SCSI commands plus any associated 
- outgoing data to it; the resulting status codes and any incoming data
- are then obtained by a read call. The device can be opened O_NONBLOCK
- (non-blocking) and poll() used to monitor its progress. The device may be
- opened O_EXCL which excludes other "sg" users from this device (but not 
- "sd", "st" or "sr" users). The buffer given to the write() call is made
- up as follows:
-        - struct sg_header image (see below)
-        - scsi command (6, 10 or 12 bytes long)
-        - data to be written to the device (if any)
-
- The buffer received from the corresponding read() call contains:
-        - struct sg_header image (check results + sense_buffer)
-        - data read back from device (if any)
-
- The given SCSI command has its LUN field overwritten internally by the
- value associated with the device that has been opened.
-
- This device currently uses "indirect IO" in the sense that data is
- DMAed into kernel buffers from the hardware and afterwards is
- transferred into the user space (or vice versa if you are writing).
- Transfer speeds or up to 20 to 30MBytes/sec have been measured using
- indirect IO. For faster throughputs "direct IO" which cuts out the
- double handling of data is required. This will also need a new interface.
-
- Grabbing memory for those kernel buffers used in this driver for DMA may
- cause the dreaded ENOMEM error. This error seems to be more prevalent 
- under early 2.2.x kernels than under the 2.0.x kernel series. For a given 
- (large) transfer the memory obtained by this driver must be contiguous or
- scatter-gather must be used (if supported by the adapter). [Furthermore, 
- ISA SCSI adapters can only use memory below the 16MB level on a i386.]
-
- When a "sg" device is open()ed O_RDWR then this driver will attempt to
- reserve a buffer of SG_DEF_RESERVED_SIZE that will be used by subsequent
- write()s on this file descriptor as long as:
-    -  it is not already in use (eg when command queuing is in use)
-    -  the write() does not call for a buffer size larger than the
-       reserved size.
- In these cases the write() will attempt to find the memory it needs for
- DMA buffers dynamically and in the worst case will fail with ENOMEM.
- The amount of memory actually reserved depends on various dynamic factors
- and can be checked with the SG_GET_RESERVED_SIZE ioctl(). [In a very
- tight memory situation it may yield 0!] The size of the reserved buffer
- can be changed with the SG_SET_RESERVED_SIZE ioctl(). It should be
- followed with a call to the SG_GET_RESERVED_SIZE ioctl() to find out how
- much was actually reserved.
 
- More documentation plus test and utility programs can be found at 
- http://www.torque.net/sg
+Map of SG verions to the Linux kernels in which they appear:
+       ----------        ----------------------------------
+       original          all kernels < 2.2.6
+       2.1.31            2.2.6 and 2.2.7
+       2.1.32            2.2.8 and 2.2.9
+       2.1.34            2.2.10 to 2.2.13
+       2.1.36            2.2.14 
+       2.3.35            2.3.x development series kernels (starting 2.3.20)
+       3.0.x             optional version 3 sg driver for 2.2 series
+       3.1.x             candidate version 3 sg driver for 2.3 series
+
+Major new features in SG 3.x driver (cf SG 2.x drivers)
+	- SG_IO ioctl() combines function if write() and read()
+	- new interface (sg_io_hdr_t) but still supports old interface
+	- scatter/gather in user space and direct IO supported
+
+Major features in SG 2.x driver (cf original SG driver)
+	- per file descriptor (fd) write-read sequencing
+	- command queuing supported
+	- scatter-gather supported at kernel level allowing potentially
+	  large transfers
+	- more SCSI status information returned
+	- asynchronous notification support added (SIGPOLL, SIGIO)
+	- read() can fetch by given pack_id
+	- uses kernel memory as appropriate for SCSI adapter being used
+	- single SG_BIG_BUFF replaced by per file descriptor "reserve
+	  buffer" whose size can be manipulated by ioctls()
+
+ The term "indirect IO" refers a method by which data is DMAed into kernel
+ buffers from the hardware and afterwards is transferred into the user
+ space (or vice versa if you are writing). Transfer speeds of up to 20 to
+ 30MBytes/sec have been measured using indirect IO. For faster throughputs
+ "direct IO" which cuts out the double handling of data is required.
+ Direct IO is supported by the SG 3.x drivers on 2.3 series Linux kernels
+ (or later) and requires the use of the new interface.
+
+ Requests for direct IO with the new interface will automatically fall back
+ to indirect IO mode if they cannot be fulfilled. An example of such a case
+ is an ISA SCSI adapter which is only capable of DMAing to the lower 16MB of
+ memory due to the architecture of ISA. The 'info' field in the new
+ interface indicates whether a direct or indirect data transfer took place.
+
+ Obtaining memory for the kernel buffers used in indirect IO is done by
+ first checking if the "reserved buffer" for the current file descriptor
+ is available and large enough. If these conditions are _not_ met then
+ kernel memory is obtained on a per SCSI command basis. This corresponds
+ to a write(), read() sequence or a SG_IO ioctl() call. Further, the
+ kernel memory that is suitable for DMA may be constrained by the
+ architecture of the SCSI adapter (e.g. ISA adapters).
+
+ Documentation
+ =============
+ A web site for SG device drivers can be found at:
+	http://www.torque.net/sg  [alternatively check the MAINTAINERS file]
+ The main documents are still based on 2.x versions:
+	http://www.torque.net/sg/p/scsi-generic.txt
+	http://www.torque.net/sg/p/scsi-generic_long.txt
+ The first document can also be found in the kernel source tree, probably at:
+	/usr/src/linux/Documentation/scsi-generic.txt .
+ Documentation on the changes and additions in 3.x version of the sg driver
+ can be found at: http://www.torque.net/sg/p/scsi-generic_v3.txt
+ Utility and test programs are also available at that web site.
 */
 
-#define SG_MAX_SENSE 16   /* too little, unlikely to change in 2.2.x */
+/* New interface introduced in the 3.x SG drivers follows */
 
-struct sg_header
+typedef struct sg_iovec /* same structure as used by readv() Linux system */
+{                       /* call. It defines one scatter-gather element. */
+    void * iov_base;            /* Starting address  */
+    size_t iov_len;             /* Length in bytes  */
+} sg_iovec_t;
+
+
+typedef struct sg_io_hdr
 {
-    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 */
+    char interface_id;          /* [i] 'S' for SCSI generic (required) */
+    unsigned char cmd_len;      /* [i] SCSI command length ( <= 16 bytes) */
+    unsigned char iovec_count;  /* [i] 0 implies no scatter gather */
+    unsigned char mx_sb_len;    /* [i] max length to write to sbp */
+    int dxfer_direction;        /* [i] data transfer direction  */
+    unsigned int dxfer_len;     /* [i] byte count of data transfer */
+    void * dxferp;              /* [i], [*io] points to data transfer memory
+					      or scatter gather list */
+    unsigned char * cmdp;       /* [i], [*i] points to command to perform */
+    unsigned char * 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 * 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;  /* 60 bytes long (on i386) */
+
+/* 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 */
+
+/* following flag values can be "or"-ed together */
+#define SG_FLAG_DIRECT_IO 1     /* default is indirect IO */
+#define SG_FLAG_LUN_INHIBIT 2   /* default is to put device's lun into */
+				/* the 2nd byte of SCSI command */
+#define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */
+				/* user space (debug indirect IO) */
+
+/* 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 {
+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 */
@@ -152,25 +170,38 @@
     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 unused1;        /* probably find a good use, set 0 for now */
-    int unused2;        /* ditto */
-} Sg_scsi_id;
+    int unused[2];      /* probably find a good use, set 0 for now */
+} sg_scsi_id_t; /* 32 bytes long on i386 */
 
-/* IOCTLs: ( _GET_s yield result via 'int *' 3rd argument unless 
-             otherwise indicated) */
-#define SG_SET_TIMEOUT 0x2201  /* unit: jiffies (10ms on i386) */
-#define SG_GET_TIMEOUT 0x2202  /* yield timeout as _return_ value */
+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 * 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 */
-#define SG_SET_TRANSFORM 0x2204
+/* 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 takes a 'Sg_scsi_id *' object as its 3rd argument. */
+/* 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 */
 
@@ -179,66 +210,111 @@
 #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
-   will attempt to read that pack_id or block (or return 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. */ 
+   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() */
 
-/* Turn on error sense trace (1..8), dump this device to log/console (9)
-   or dump all sg device states ( >9 ) to log/console */
-#define SG_SET_DEBUG 0x227e    /* 0 -> turn off debug */
-
 /* Yields max scatter gather tablesize allowed by current host adapter */
 #define SG_GET_SG_TABLESIZE 0x227F  /* 0 implies can't do scatter gather */
 
-/* Control whether sequencing per file descriptor or per device */
-#define SG_GET_MERGE_FD 0x2274   /* 0-> per fd, 1-> per device */
-#define SG_SET_MERGE_FD 0x2273   /* Attempt to change sequencing state,
-  if more than current fd open on device, will fail with EBUSY */
-
-/* Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q) */
-#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 */
-
-/* Get/set whether DMA underrun will cause an error (DID_ERROR). This only
-   currently applies to the [much-used] aic7xxx driver. */
-#define SG_GET_UNDERRUN_FLAG 0x2280 /* Yields 0 (don't flag) or 1 (flag) */
-#define SG_SET_UNDERRUN_FLAG 0x2281 /* Change flag underrun state */
-
 #define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */
-#define SG_NEXT_CMD_LEN 0x2283  /* override SCSI command length with given
-                   number on the next write() on this file descriptor */
 
 /* Returns -EBUSY if occupied else takes as input: 0 -> do nothing,
    1 -> device reset or  2 -> bus reset (may not be activated yet) */
 #define SG_SCSI_RESET 0x2284
 
+/* 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
+
 
 #define SG_SCATTER_SZ (8 * 4096)  /* PAGE_SIZE not available to user */
 /* Largest size (in bytes) a single scatter-gather list element can have.
-   The value must be a power of 2 and <= (PAGE_SIZE * 32) [131072 bytes on 
+   The value must be a power of 2 and <= (PAGE_SIZE * 32) [131072 bytes on
    i386]. The minimum value is PAGE_SIZE. If scatter-gather not supported
    by adapter then this value is the largest data block that can be
    read/written by a single scsi command. The user can find the value of
    PAGE_SIZE by calling getpagesize() defined in unistd.h . */
 
-#define SG_DEFAULT_TIMEOUT (60*HZ) /* HZ == 'jiffies in 1 second' */
 #define SG_DEFAULT_RETRIES 1
 
 /* Defaults, commented if they differ from original sg driver */
-#define SG_DEF_COMMAND_Q 0
-#define SG_DEF_MERGE_FD 0       /* was 1 -> per device sequencing */
 #define SG_DEF_FORCE_LOW_DMA 0  /* was 1 -> memory below 16MB on i386 */
 #define SG_DEF_FORCE_PACK_ID 0
-#define SG_DEF_UNDERRUN_FLAG 0
-#define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ
+#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. That 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 */
+#define SG_DEFAULT_TIMEOUT (60*HZ) /* HZ == 'jiffies in 1 second' */
+#define SG_DEF_COMMAND_Q 0     /* command queuing is always on when
+				  the new interface is used */
+#define SG_DEF_UNDERRUN_FLAG 0
 
 #endif
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