sys/sys/msgport.h

   1 /*
   2  * SYS/MSGPORT.H
   3  *
   4  *      Implements LWKT messages and ports.
   5  *
   6  * $DragonFly: src/sys/sys/msgport.h,v 1.27 2008/03/05 13:03:29 sephe Exp $
   7  */
   8
   9 #ifndef _SYS_MSGPORT_H_
  10 #define _SYS_MSGPORT_H_
  11
  12 #ifndef _SYS_QUEUE_H_
  13 #include <sys/queue.h>          /* TAILQ_* macros */
  14 #endif
  15 #ifndef _SYS_STDINT_H_
  16 #include <sys/stdint.h>
  17 #endif
  18 #ifndef _SYS_SPINLOCK_H_
  19 #include <sys/spinlock.h>
  20 #endif
  21
  22 #ifdef _KERNEL
  23
  24 #ifndef _SYS_MALLOC_H_
  25 #include <sys/malloc.h>
  26 #endif
  27
  28 #endif
  29
  30 struct lwkt_msg;
  31 struct lwkt_port;
  32 struct lwkt_serialize;
  33 struct thread;
  34
  35 typedef struct lwkt_msg         *lwkt_msg_t;
  36 typedef struct lwkt_port        *lwkt_port_t;
  37
  38 typedef TAILQ_HEAD(lwkt_msg_queue, lwkt_msg) lwkt_msg_queue;
  39
  40 /*
  41  * The standard message and port structure for communications between
  42  * threads.  See kern/lwkt_msgport.c for documentation on how messages and
  43  * ports work.
  44  *
  45  * A message may only be manipulated by whomever currently owns it,
  46  * which generally means the originating port if the message has
  47  * not been sent yet or has been replied, and the target port if the message
  48  * has been sent and/or is undergoing processing.
  49  *
  50  * NOTE! 64-bit-align this structure.
  51  */
  52 typedef struct lwkt_msg {
  53     TAILQ_ENTRY(lwkt_msg) ms_node;      /* link node */
  54     lwkt_port_t ms_target_port;         /* current target or relay port */
  55     lwkt_port_t ms_reply_port;          /* async replies returned here */
  56     void        (*ms_abortfn)(struct lwkt_msg *);
  57     int         ms_flags;               /* message flags */
  58     int         ms_error;               /* positive error code or 0 */
  59     union {
  60         void    *ms_resultp;            /* misc pointer data or result */
  61         int     ms_result;              /* standard 'int'eger result */
  62         long    ms_lresult;             /* long result */
  63         int     ms_fds[2];              /* two int bit results */
  64         __int32_t ms_result32;          /* 32 bit result */
  65         __int64_t ms_result64;          /* 64 bit result */
  66         __off_t ms_offset;              /* off_t result */
  67     } u;
  68     int         ms_pad[2];              /* future use */
  69 } lwkt_msg;
  70
  71 /*
  72  * Message state flags are manipulated by the current owner only.
  73  *
  74  * DONE         Indicates completion of the reply.  This flag is also set
  75  *              for unsent messages.
  76  *
  77  * REPLY        Indicates message is being replied but may or may not
  78  *              have been queued or returned yet.  This bit is left set
  79  *              when a message is retrieved from a reply port so the caller
  80  *              can distinguish between requests and replies.
  81  *
  82  * QUEUED       Indicates message is queued on reply or target port, or
  83  *              some other port.
  84  *
  85  * SYNC         Indicates that the originator is blocked directly on the
  86  *              message and that the message should be signaled on
  87  *              completion instead of queued.
  88  *
  89  * INTRANSIT    Indicates that the message state is indeterminant (e.g.
  90  *              being passed through an IPI).
  91  *
  92  * ABORTABLE    Static flag indicates that ms_abortfn is valid.
  93  */
  94 #define MSGF_DONE       0x0001          /* message is complete */
  95 #define MSGF_REPLY      0x0002          /* asynch message has been returned */
  96 #define MSGF_QUEUED     0x0004          /* message has been queued sanitychk */
  97 #define MSGF_SYNC       0x0008          /* synchronous message operation */
  98 #define MSGF_INTRANSIT  0x0010          /* in-transit (IPI) */
  99 #define MSGF_ABORTABLE  0x0080          /* message supports abort */
 100
 101 #define MSG_CMD_CDEV    0x00010000
 102 #define MSG_CMD_VFS     0x00020000
 103 #define MSG_CMD_SYSCALL 0x00030000
 104 #define MSG_SUBCMD_MASK 0x0000FFFF
 105
 106 #ifdef _KERNEL
 107 MALLOC_DECLARE(M_LWKTMSG);
 108 #endif
 109
 110 /*
 111  * Notes on port processing requirements:
 112  *
 113  * mp_putport():
 114  *      - may return synchronous error code (error != EASYNC) directly and
 115  *        does not need to check or set MSGF_DONE if so, or set ms_target_port
 116  *      - for asynch procesing should clear MSGF_DONE and set ms_target_port
 117  *        to port prior to initiation of the command.
 118  *
 119  * mp_waitmsg():
 120  *      - wait for a particular message to be returned.
 121  *
 122  * mp_waitport():
 123  *      - wait for a new message on the specified port.
 124  *
 125  * mp_replyport():
 126  *      - reply a message (executed on the originating port to return a
 127  *        message to it).  This can be rather involved if abort is to be
 128  *        supported, see lwkt_default_replyport().  Generally speaking
 129  *        one sets MSGF_DONE.  If MSGF_SYNC is set the message is not
 130  *        queued to the port and the reply code wakes up the waiter
 131  *        directly.
 132  *
 133  * The use of mp_u.td and mp_u.spin is specific to the port callback function
 134  * set.  Default ports are tied to specific threads and use cpu locality
 135  * of reference and mp_u.td (and not mp_u.spin at all).  Descriptor ports
 136  * assume access via descriptors, signal interruption, etc.  Such ports use
 137  * mp_u.spin (and not mp_u.td at all) and may be accessed by multiple threads.
 138  */
 139 typedef struct lwkt_port {
 140     lwkt_msg_queue      mp_msgq;
 141     int                 mp_flags;
 142     union {
 143         struct spinlock spin;
 144         struct thread   *td;
 145         struct lwkt_serialize *serialize;
 146         void            *data;
 147     } mp_u;
 148     void *              (*mp_getport)(lwkt_port_t);
 149     int                 (*mp_putport)(lwkt_port_t, lwkt_msg_t);
 150     int                 (*mp_waitmsg)(lwkt_msg_t, int flags);
 151     void *              (*mp_waitport)(lwkt_port_t, int flags);
 152     void                (*mp_replyport)(lwkt_port_t, lwkt_msg_t);
 153 } lwkt_port;
 154
 155 #ifdef _KERNEL
 156
 157 #define mpu_td          mp_u.td
 158 #define mpu_spin        mp_u.spin
 159 #define mpu_serialize   mp_u.serialize
 160 #define mpu_data        mp_u.data
 161
 162 #endif
 163
 164 #define MSGPORTF_WAITING        0x0001
 165
 166 /*
 167  * These functions are good for userland as well as the kernel.  The
 168  * messaging function support for userland is provided by the kernel's
 169  * kern/lwkt_msgport.c.  The port functions are provided by userland.
 170  */
 171
 172 void lwkt_initport_thread(lwkt_port_t, struct thread *);
 173 void lwkt_initport_spin(lwkt_port_t);
 174 void lwkt_initport_serialize(lwkt_port_t, struct lwkt_serialize *);
 175 void lwkt_initport_panic(lwkt_port_t);
 176 void lwkt_initport_replyonly_null(lwkt_port_t);
 177 void lwkt_initport_replyonly(lwkt_port_t,
 178                                 void (*rportfn)(lwkt_port_t, lwkt_msg_t));
 179 void lwkt_initport_putonly(lwkt_port_t,
 180                                 int (*pportfn)(lwkt_port_t, lwkt_msg_t));
 181
 182 void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t);
 183 int lwkt_domsg(lwkt_port_t, lwkt_msg_t, int);
 184 int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t);
 185 void lwkt_abortmsg(lwkt_msg_t);
 186
 187 #endif