1 /* 2 * SYS/MSGPORT.H 3 * 4 * Implements LWKT messages and ports. 5 * 6 * $DragonFly: src/sys/sys/msgport.h,v 1.21 2004/12/21 19:41:36 dillon 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 19 struct lwkt_msg; 20 struct lwkt_port; 21 struct thread; 22 23 typedef struct lwkt_msg *lwkt_msg_t; 24 typedef struct lwkt_port *lwkt_port_t; 25 26 typedef TAILQ_HEAD(lwkt_msg_queue, lwkt_msg) lwkt_msg_queue; 27 28 /* 29 * LWKT command message operator type. This type holds a message's 30 * 'command'. The command format is opaque to the LWKT messaging system, 31 * meaning that it is specific to whatever convention the API chooses. 32 * By convention lwkt_cmd_t is passed by value and is expected to 33 * efficiently fit into a machine register. 34 */ 35 typedef union lwkt_cmd { 36 int cm_op; 37 int (*cm_func)(lwkt_msg_t msg); 38 } lwkt_cmd_t; 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 * For the most part a message may only be manipulated by whomever currently 46 * owns it, 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 * The one exception to this rule is an abort. Aborts must be initiated 51 * by the originator and may 'chase' the target (especially if a message 52 * is being forwarded), potentially even 'chase' the message all the way 53 * back to the originator if it races against the target replying the 54 * message. The ms_abort_port field is the only field that may be modified 55 * by the originator or intermediate target (when the abort is chasing 56 * a forwarding or reply op). An abort may cause a reply to be delayed 57 * until the abort catches up to it. 58 * 59 * Messages which support an abort will have MSGF_ABORTABLE set, indicating 60 * that the ms_abort field has been initialized. An abort will cause a 61 * message to be requeued to the target port so the target sees the same 62 * message twice: once during initial processing of the message, and a 63 * second time to process the abort request. lwkt_getport() will detect 64 * the requeued abort and will copy ms_abort into ms_cmd before returning 65 * the requeued message the second time. This makes target processing a 66 * whole lot less complex. 67 * 68 * NOTE! 64-bit-align this structure. 69 */ 70 typedef struct lwkt_msg { 71 TAILQ_ENTRY(lwkt_msg) ms_node; /* link node */ 72 union { 73 struct lwkt_msg *ms_next; /* chaining / cache */ 74 union sysunion *ms_sysunnext; /* chaining / cache */ 75 struct lwkt_msg *ms_umsg; /* user message (UVA address) */ 76 } opaque; 77 lwkt_port_t ms_target_port; /* current target or relay port */ 78 lwkt_port_t ms_reply_port; /* async replies returned here */ 79 lwkt_port_t ms_abort_port; /* abort chasing port */ 80 lwkt_cmd_t ms_cmd; /* message command operator */ 81 lwkt_cmd_t ms_abort; /* message abort operator */ 82 int ms_flags; /* message flags */ 83 #define ms_copyout_start ms_msgsize 84 int ms_msgsize; /* size of message */ 85 int ms_error; /* positive error code or 0 */ 86 union { 87 void *ms_resultp; /* misc pointer data or result */ 88 int ms_result; /* standard 'int'eger result */ 89 long ms_lresult; /* long result */ 90 int ms_fds[2]; /* two int bit results */ 91 __int32_t ms_result32; /* 32 bit result */ 92 __int64_t ms_result64; /* 64 bit result */ 93 __off_t ms_offset; /* off_t result */ 94 } u; 95 #define ms_copyout_end ms_pad[0] 96 int ms_pad[2]; /* future use */ 97 } lwkt_msg; 98 99 #define ms_copyout_size (offsetof(struct lwkt_msg, ms_copyout_end) - offsetof(struct lwkt_msg, ms_copyout_start)) 100 101 #define MSGF_DONE 0x0001 /* asynch message is complete */ 102 #define MSGF_REPLY1 0x0002 /* asynch message has been returned */ 103 #define MSGF_QUEUED 0x0004 /* message has been queued sanitychk */ 104 #define MSGF_ASYNC 0x0008 /* sync/async hint */ 105 #define MSGF_ABORTED 0x0010 /* indicate pending abort */ 106 #define MSGF_PCATCH 0x0020 /* catch proc signal while waiting */ 107 #define MSGF_REPLY2 0x0040 /* reply processed by rport cpu */ 108 #define MSGF_ABORTABLE 0x0080 /* message supports abort */ 109 #define MSGF_RETRIEVED 0x0100 /* message retrieved on target */ 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 #ifdef MALLOC_DECLARE 118 MALLOC_DECLARE(M_LWKTMSG); 119 #endif 120 #endif 121 122 /* 123 * Notes on port processing requirements: 124 * 125 * mp_putport(): 126 * - may return synchronous error code (error != EASYNC) directly and 127 * does not need to check or set MSGF_DONE if so, or set ms_target_port 128 * - for asynch procesing should clear MSGF_DONE and set ms_target_port 129 * to port prior to initiation of the command. 130 * 131 * mp_waitport(): 132 * - if the passed msg is NULL we wait for, remove, and return the 133 * next pending message on the port. 134 * - if the passed msg is non-NULL we wait for that particular message, 135 * which typically involves waiting until MSGF_DONE is set then 136 * pulling the message off the port if MSGF_QUEUED is set and 137 * returning it. If MSGF_PCATCH is set in the message we allow 138 * a signal to interrupt and abort the message. 139 * 140 * mp_replyport(): 141 * - reply a message (executed on the originating port to return a 142 * message to it). This can be rather involved if abort is to be 143 * supported, see lwkt_default_replyport(). Generally speaking 144 * one sets MSGF_DONE. If MSGF_ASYNC is set the message is queued 145 * to the port, else the port's thread is scheduled. 146 * 147 * mp_abortport(): 148 * - abort a message. The mp_abortport function for the message's 149 * ms_target_port is called. ms_target_port is basically where 150 * the message was sent to or last forwarded to. Aborting a message 151 * can be rather involved. Note that the lwkt_getmsg() code ensures 152 * that a message is returned non-abort before it is returned again 153 * with its ms_cmd set to ms_abort, even if the abort occurs before 154 * the initial retrieval of the message. The setting of ms_cmd to 155 * ms_abort is NOT handled by mp_abortport(). mp_abortport() is 156 * basically responsible for requeueing the message to the target 157 * port and setting the MSGF_ABORTED flag. 158 * 159 */ 160 typedef struct lwkt_port { 161 lwkt_msg_queue mp_msgq; 162 int mp_flags; 163 int mp_unused01; 164 struct thread *mp_td; 165 int (*mp_putport)(lwkt_port_t, lwkt_msg_t); 166 void * (*mp_waitport)(lwkt_port_t, lwkt_msg_t); 167 void (*mp_replyport)(lwkt_port_t, lwkt_msg_t); 168 void (*mp_abortport)(lwkt_port_t, lwkt_msg_t); 169 } lwkt_port; 170 171 #define MSGPORTF_WAITING 0x0001 172 173 /* 174 * These functions are good for userland as well as the kernel. The 175 * messaging function support for userland is provided by the kernel's 176 * kern/lwkt_msgport.c. The port functions are provided by userland. 177 */ 178 void lwkt_initport(lwkt_port_t, struct thread *); 179 void lwkt_initport_null_rport(lwkt_port_t, struct thread *); 180 void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t); 181 int lwkt_domsg(lwkt_port_t, lwkt_msg_t); 182 int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t); 183 void lwkt_abortmsg(lwkt_msg_t); 184 void *lwkt_getport(lwkt_port_t); 185 186 int lwkt_default_putport(lwkt_port_t port, lwkt_msg_t msg); 187 void *lwkt_default_waitport(lwkt_port_t port, lwkt_msg_t msg); 188 void lwkt_default_replyport(lwkt_port_t port, lwkt_msg_t msg); 189 void lwkt_default_abortport(lwkt_port_t port, lwkt_msg_t msg); 190 void lwkt_null_replyport(lwkt_port_t port, lwkt_msg_t msg); 191 192 #endif 193