4 * Implements LWKT messages and ports.
6 * $DragonFly: src/sys/sys/msgport.h,v 1.22 2006/05/20 06:32:41 dillon Exp $
9 #ifndef _SYS_MSGPORT_H_
10 #define _SYS_MSGPORT_H_
13 #include <sys/queue.h> /* TAILQ_* macros */
15 #ifndef _SYS_STDINT_H_
16 #include <sys/stdint.h>
21 #ifndef _SYS_MALLOC_H_
22 #include <sys/malloc.h>
31 typedef struct lwkt_msg *lwkt_msg_t;
32 typedef struct lwkt_port *lwkt_port_t;
34 typedef TAILQ_HEAD(lwkt_msg_queue, lwkt_msg) lwkt_msg_queue;
37 * LWKT command message operator type. This type holds a message's
38 * 'command'. The command format is opaque to the LWKT messaging system,
39 * meaning that it is specific to whatever convention the API chooses.
40 * By convention lwkt_cmd_t is passed by value and is expected to
41 * efficiently fit into a machine register.
43 typedef union lwkt_cmd {
45 int (*cm_func)(lwkt_msg_t msg);
49 * The standard message and port structure for communications between
50 * threads. See kern/lwkt_msgport.c for documentation on how messages and
53 * For the most part a message may only be manipulated by whomever currently
54 * owns it, which generally means the originating port if the message has
55 * not been sent yet or has been replied, and the target port if the message
56 * has been sent and/or is undergoing processing.
58 * The one exception to this rule is an abort. Aborts must be initiated
59 * by the originator and may 'chase' the target (especially if a message
60 * is being forwarded), potentially even 'chase' the message all the way
61 * back to the originator if it races against the target replying the
62 * message. The ms_abort_port field is the only field that may be modified
63 * by the originator or intermediate target (when the abort is chasing
64 * a forwarding or reply op). An abort may cause a reply to be delayed
65 * until the abort catches up to it.
67 * Messages which support an abort will have MSGF_ABORTABLE set, indicating
68 * that the ms_abort field has been initialized. An abort will cause a
69 * message to be requeued to the target port so the target sees the same
70 * message twice: once during initial processing of the message, and a
71 * second time to process the abort request. lwkt_getport() will detect
72 * the requeued abort and will copy ms_abort into ms_cmd before returning
73 * the requeued message the second time. This makes target processing a
74 * whole lot less complex.
76 * NOTE! 64-bit-align this structure.
78 typedef struct lwkt_msg {
79 TAILQ_ENTRY(lwkt_msg) ms_node; /* link node */
81 struct lwkt_msg *ms_next; /* chaining / cache */
82 union sysunion *ms_sysunnext; /* chaining / cache */
83 struct lwkt_msg *ms_umsg; /* user message (UVA address) */
85 lwkt_port_t ms_target_port; /* current target or relay port */
86 lwkt_port_t ms_reply_port; /* async replies returned here */
87 lwkt_port_t ms_abort_port; /* abort chasing port */
88 lwkt_cmd_t ms_cmd; /* message command operator */
89 lwkt_cmd_t ms_abort; /* message abort operator */
90 int ms_flags; /* message flags */
91 #define ms_copyout_start ms_msgsize
92 int ms_msgsize; /* size of message */
93 int ms_error; /* positive error code or 0 */
95 void *ms_resultp; /* misc pointer data or result */
96 int ms_result; /* standard 'int'eger result */
97 long ms_lresult; /* long result */
98 int ms_fds[2]; /* two int bit results */
99 __int32_t ms_result32; /* 32 bit result */
100 __int64_t ms_result64; /* 64 bit result */
101 __off_t ms_offset; /* off_t result */
103 #define ms_copyout_end ms_pad[0]
104 int ms_pad[2]; /* future use */
107 #define ms_copyout_size (offsetof(struct lwkt_msg, ms_copyout_end) - offsetof(struct lwkt_msg, ms_copyout_start))
109 #define MSGF_DONE 0x0001 /* asynch message is complete */
110 #define MSGF_REPLY1 0x0002 /* asynch message has been returned */
111 #define MSGF_QUEUED 0x0004 /* message has been queued sanitychk */
112 #define MSGF_ASYNC 0x0008 /* sync/async hint */
113 #define MSGF_ABORTED 0x0010 /* indicate pending abort */
114 #define MSGF_PCATCH 0x0020 /* catch proc signal while waiting */
115 #define MSGF_REPLY2 0x0040 /* reply processed by rport cpu */
116 #define MSGF_ABORTABLE 0x0080 /* message supports abort */
117 #define MSGF_RETRIEVED 0x0100 /* message retrieved on target */
119 #define MSG_CMD_CDEV 0x00010000
120 #define MSG_CMD_VFS 0x00020000
121 #define MSG_CMD_SYSCALL 0x00030000
122 #define MSG_SUBCMD_MASK 0x0000FFFF
125 MALLOC_DECLARE(M_LWKTMSG);
129 * Notes on port processing requirements:
132 * - may return synchronous error code (error != EASYNC) directly and
133 * does not need to check or set MSGF_DONE if so, or set ms_target_port
134 * - for asynch procesing should clear MSGF_DONE and set ms_target_port
135 * to port prior to initiation of the command.
138 * - if the passed msg is NULL we wait for, remove, and return the
139 * next pending message on the port.
140 * - if the passed msg is non-NULL we wait for that particular message,
141 * which typically involves waiting until MSGF_DONE is set then
142 * pulling the message off the port if MSGF_QUEUED is set and
143 * returning it. If MSGF_PCATCH is set in the message we allow
144 * a signal to interrupt and abort the message.
147 * - reply a message (executed on the originating port to return a
148 * message to it). This can be rather involved if abort is to be
149 * supported, see lwkt_default_replyport(). Generally speaking
150 * one sets MSGF_DONE. If MSGF_ASYNC is set the message is queued
151 * to the port, else the port's thread is scheduled.
154 * - abort a message. The mp_abortport function for the message's
155 * ms_target_port is called. ms_target_port is basically where
156 * the message was sent to or last forwarded to. Aborting a message
157 * can be rather involved. Note that the lwkt_getmsg() code ensures
158 * that a message is returned non-abort before it is returned again
159 * with its ms_cmd set to ms_abort, even if the abort occurs before
160 * the initial retrieval of the message. The setting of ms_cmd to
161 * ms_abort is NOT handled by mp_abortport(). mp_abortport() is
162 * basically responsible for requeueing the message to the target
163 * port and setting the MSGF_ABORTED flag.
166 typedef struct lwkt_port {
167 lwkt_msg_queue mp_msgq;
170 struct thread *mp_td;
171 int (*mp_putport)(lwkt_port_t, lwkt_msg_t);
172 void * (*mp_waitport)(lwkt_port_t, lwkt_msg_t);
173 void (*mp_replyport)(lwkt_port_t, lwkt_msg_t);
174 void (*mp_abortport)(lwkt_port_t, lwkt_msg_t);
177 #define MSGPORTF_WAITING 0x0001
180 * These functions are good for userland as well as the kernel. The
181 * messaging function support for userland is provided by the kernel's
182 * kern/lwkt_msgport.c. The port functions are provided by userland.
184 void lwkt_initport(lwkt_port_t, struct thread *);
185 void lwkt_initport_null_rport(lwkt_port_t, struct thread *);
186 void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t);
187 int lwkt_domsg(lwkt_port_t, lwkt_msg_t);
188 int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t);
189 void lwkt_abortmsg(lwkt_msg_t);
190 void *lwkt_getport(lwkt_port_t);
192 int lwkt_default_putport(lwkt_port_t port, lwkt_msg_t msg);
193 void *lwkt_default_waitport(lwkt_port_t port, lwkt_msg_t msg);
194 void lwkt_default_replyport(lwkt_port_t port, lwkt_msg_t msg);
195 void lwkt_default_abortport(lwkt_port_t port, lwkt_msg_t msg);
196 void lwkt_null_replyport(lwkt_port_t port, lwkt_msg_t msg);