Change sendfile() to use the new m_ext callback scheme for cleaning up after
[dragonfly.git] / sys / sys / msgport.h
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1/*
2 * SYS/MSGPORT.H
3 *
4 * Implements LWKT messages and ports.
5 *
3efe7008 6 * $DragonFly: src/sys/sys/msgport.h,v 1.19 2004/06/07 07:01:36 dillon Exp $
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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
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15#ifndef _SYS_STDINT_H_
16#include <sys/stdint.h>
17#endif
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18
19struct lwkt_msg;
20struct lwkt_port;
335dda38 21struct thread;
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22
23typedef struct lwkt_msg *lwkt_msg_t;
24typedef struct lwkt_port *lwkt_port_t;
25
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26typedef TAILQ_HEAD(lwkt_msg_queue, lwkt_msg) lwkt_msg_queue;
27
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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 */
35typedef union lwkt_cmd {
36 int cm_op;
37 int (*cm_func)(lwkt_msg_t msg);
38} lwkt_cmd_t;
39
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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.
a64ba182 44 *
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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 *
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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.
e7906ee5 67 *
a64ba182 68 * NOTE! 64-bit-align this structure.
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69 */
70typedef struct lwkt_msg {
e7906ee5 71 TAILQ_ENTRY(lwkt_msg) ms_node; /* link node (see note above) */
4fd10eb6 72 union {
c7114eea 73 struct lwkt_msg *ms_next; /* chaining / cache */
245e4f17 74 union sysunion *ms_sysunnext; /* chaining / cache */
c7114eea 75 struct lwkt_msg *ms_umsg; /* user message (UVA address) */
4fd10eb6 76 } opaque;
df2244e3 77 lwkt_port_t ms_target_port; /* current target or relay port */
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78 lwkt_port_t ms_reply_port; /* async replies returned here */
79 lwkt_port_t ms_abort_port; /* abort chasing port */
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80 lwkt_cmd_t ms_cmd; /* message command operator */
81 lwkt_cmd_t ms_abort; /* message abort operator */
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82 int ms_flags; /* message flags */
83#define ms_copyout_start ms_msgsize
f6bf3af1 84 int ms_msgsize; /* size of message */
df2244e3 85 int ms_error; /* positive error code or 0 */
a64ba182 86 union {
df2244e3 87 void *ms_resultp; /* misc pointer data or result */
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88 int ms_result; /* standard 'int'eger result */
89 long ms_lresult; /* long result */
90 int ms_fds[2]; /* two int bit results */
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91 __int32_t ms_result32; /* 32 bit result */
92 __int64_t ms_result64; /* 64 bit result */
93 __off_t ms_offset; /* off_t result */
a64ba182 94 } u;
245e4f17 95#define ms_copyout_end ms_pad[0]
a64ba182 96 int ms_pad[2]; /* future use */
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97} lwkt_msg;
98
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99#define ms_copyout_size (offsetof(struct lwkt_msg, ms_copyout_end) - offsetof(struct lwkt_msg, ms_copyout_start))
100
ece04fd0 101#define MSGF_DONE 0x0001 /* asynch message is complete */
e7906ee5 102#define MSGF_REPLY1 0x0002 /* asynch message has been returned */
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103#define MSGF_QUEUED 0x0004 /* message has been queued sanitychk */
104#define MSGF_ASYNC 0x0008 /* sync/async hint */
b44419cb 105#define MSGF_ABORTED 0x0010 /* indicate pending abort */
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106#define MSGF_PCATCH 0x0020 /* catch proc signal while waiting */
107#define MSGF_REPLY2 0x0040 /* reply processed by rport cpu */
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108#define MSGF_ABORTABLE 0x0080 /* message supports abort */
109#define MSGF_RETRIEVED 0x0100 /* message retrieved on target */
ece04fd0 110
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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
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116#ifdef _KERNEL
117#ifdef MALLOC_DECLARE
118MALLOC_DECLARE(M_LWKTMSG);
119#endif
120#endif
121
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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 */
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160typedef struct lwkt_port {
161 lwkt_msg_queue mp_msgq;
162 int mp_flags;
1fa2b4b4 163 int mp_unused01;
335dda38 164 struct thread *mp_td;
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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);
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169} lwkt_port;
170
171#define MSGPORTF_WAITING 0x0001
172
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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 */
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178void lwkt_initport(lwkt_port_t, struct thread *);
179void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t);
180int lwkt_domsg(lwkt_port_t, lwkt_msg_t);
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181int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t);
182void lwkt_abortmsg(lwkt_msg_t);
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183void *lwkt_getport(lwkt_port_t);
184
185int lwkt_default_putport(lwkt_port_t port, lwkt_msg_t msg);
186void *lwkt_default_waitport(lwkt_port_t port, lwkt_msg_t msg);
187void lwkt_default_replyport(lwkt_port_t port, lwkt_msg_t msg);
188void lwkt_default_abortport(lwkt_port_t port, lwkt_msg_t msg);
ece04fd0 189
ece04fd0 190#endif