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 1.32 2008/11/26 15:05:42 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  * High 16 bits are available to message handlers.
  95  */
  96 #define MSGF_DONE       0x0001          /* message is complete */
  97 #define MSGF_REPLY      0x0002          /* asynch message has been returned */
  98 #define MSGF_QUEUED     0x0004          /* message has been queued sanitychk */
  99 #define MSGF_SYNC       0x0008          /* synchronous message operation */
 100 #define MSGF_INTRANSIT  0x0010          /* in-transit (IPI) */
 101 #define MSGF_NORESCHED  0x0020          /* do not reschedule target lwkt */
 102 #define MSGF_DROPABLE   0x0040          /* message supports drop */
 103 #define MSGF_ABORTABLE  0x0080          /* message supports abort */
 104 #define MSGF_PRIORITY   0x0100          /* priority message */
 105
 106 #define MSGF_USER0      0x00010000
 107 #define MSGF_USER1      0x00020000
 108 #define MSGF_USER2      0x00040000
 109 #define MSGF_USER3      0x00080000
 110
 111 #define MSG_CMD_CDEV    0x00010000
 112 #define MSG_CMD_VFS     0x00020000
 113 #define MSG_CMD_SYSCALL 0x00030000
 114 #define MSG_SUBCMD_MASK 0x0000FFFF
 115
 116 #ifdef _KERNEL
 117 MALLOC_DECLARE(M_LWKTMSG);
 118 #endif
 119
 120 /*
 121  * Notes on port processing requirements:
 122  *
 123  * mp_putport():
 124  *      - may return synchronous error code (error != EASYNC) directly and
 125  *        does not need to check or set MSGF_DONE if so, or set ms_target_port
 126  *      - for asynch procesing should clear MSGF_DONE and set ms_target_port
 127  *        to port prior to initiation of the command.
 128  *
 129  * mp_waitmsg():
 130  *      - wait for a particular message to be returned.
 131  *
 132  * mp_waitport():
 133  *      - wait for a new message on the specified port.
 134  *
 135  * mp_replyport():
 136  *      - reply a message (executed on the originating port to return a
 137  *        message to it).  This can be rather involved if abort is to be
 138  *        supported, see lwkt_default_replyport().  Generally speaking
 139  *        one sets MSGF_DONE.  If MSGF_SYNC is set the message is not
 140  *        queued to the port and the reply code wakes up the waiter
 141  *        directly.
 142  *
 143  * The use of mp_u.td and mp_u.spin is specific to the port callback function
 144  * set.  Default ports are tied to specific threads and use cpu locality
 145  * of reference and mp_u.td (and not mp_u.spin at all).  Descriptor ports
 146  * assume access via descriptors, signal interruption, etc.  Such ports use
 147  * mp_u.spin (and not mp_u.td at all) and may be accessed by multiple threads.
 148  */
 149 typedef struct lwkt_port {
 150     lwkt_msg_queue      mp_msgq;
 151     lwkt_msg_queue      mp_msgq_prio;
 152     int                 mp_flags;
 153     union {
 154         struct spinlock spin;
 155         struct thread   *td;
 156         struct lwkt_serialize *serialize;
 157         void            *data;
 158     } mp_u;
 159     void *              (*mp_getport)(lwkt_port_t);
 160     int                 (*mp_putport)(lwkt_port_t, lwkt_msg_t);
 161     int                 (*mp_waitmsg)(lwkt_msg_t, int flags);
 162     void *              (*mp_waitport)(lwkt_port_t, int flags);
 163     void                (*mp_replyport)(lwkt_port_t, lwkt_msg_t);
 164     void                (*mp_dropmsg)(lwkt_port_t, lwkt_msg_t);
 165 } lwkt_port;
 166
 167 #ifdef _KERNEL
 168
 169 #define mpu_td          mp_u.td
 170 #define mpu_spin        mp_u.spin
 171 #define mpu_serialize   mp_u.serialize
 172 #define mpu_data        mp_u.data
 173
 174 #endif
 175
 176 #define MSGPORTF_WAITING        0x0001
 177
 178 /*
 179  * These functions are good for userland as well as the kernel.  The
 180  * messaging function support for userland is provided by the kernel's
 181  * kern/lwkt_msgport.c.  The port functions are provided by userland.
 182  */
 183
 184 void lwkt_initport_thread(lwkt_port_t, struct thread *);
 185 void lwkt_initport_spin(lwkt_port_t);
 186 void lwkt_initport_serialize(lwkt_port_t, struct lwkt_serialize *);
 187 void lwkt_initport_panic(lwkt_port_t);
 188 void lwkt_initport_replyonly_null(lwkt_port_t);
 189 void lwkt_initport_replyonly(lwkt_port_t,
 190                                 void (*rportfn)(lwkt_port_t, lwkt_msg_t));
 191 void lwkt_initport_putonly(lwkt_port_t,
 192                                 int (*pportfn)(lwkt_port_t, lwkt_msg_t));
 193
 194 void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t);
 195 int lwkt_domsg(lwkt_port_t, lwkt_msg_t, int);
 196 int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t);
 197 void lwkt_abortmsg(lwkt_msg_t);
 198
 199 #endif