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linux-next/include/linux/msg.h
Nadia Derbey 68aa0a206a ipc: restore MSGPOOL original value
When posting:

	[PATCH 1/8] Scaling msgmni to the amount of lowmem

(see http://article.gmane.org/gmane.linux.kernel/637849/) I changed the
MSGPOOL value to make it fit what is said in the man pages (i.e.  a size
in bytes).

But Michael Kerrisk rightly complained that this change could affect the
ABI.  So I'm posting this patch to make MSGPOOL expressed back in Kbytes.
Michael, on his side, has fixed the man page.

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Acked-by: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06 11:29:12 -07:00

113 lines
3.6 KiB
C

#ifndef _LINUX_MSG_H
#define _LINUX_MSG_H
#include <linux/ipc.h>
/* ipcs ctl commands */
#define MSG_STAT 11
#define MSG_INFO 12
/* msgrcv options */
#define MSG_NOERROR 010000 /* no error if message is too big */
#define MSG_EXCEPT 020000 /* recv any msg except of specified type.*/
/* Obsolete, used only for backwards compatibility and libc5 compiles */
struct msqid_ds {
struct ipc_perm msg_perm;
struct msg *msg_first; /* first message on queue,unused */
struct msg *msg_last; /* last message in queue,unused */
__kernel_time_t msg_stime; /* last msgsnd time */
__kernel_time_t msg_rtime; /* last msgrcv time */
__kernel_time_t msg_ctime; /* last change time */
unsigned long msg_lcbytes; /* Reuse junk fields for 32 bit */
unsigned long msg_lqbytes; /* ditto */
unsigned short msg_cbytes; /* current number of bytes on queue */
unsigned short msg_qnum; /* number of messages in queue */
unsigned short msg_qbytes; /* max number of bytes on queue */
__kernel_ipc_pid_t msg_lspid; /* pid of last msgsnd */
__kernel_ipc_pid_t msg_lrpid; /* last receive pid */
};
/* Include the definition of msqid64_ds */
#include <asm/msgbuf.h>
/* message buffer for msgsnd and msgrcv calls */
struct msgbuf {
long mtype; /* type of message */
char mtext[1]; /* message text */
};
/* buffer for msgctl calls IPC_INFO, MSG_INFO */
struct msginfo {
int msgpool;
int msgmap;
int msgmax;
int msgmnb;
int msgmni;
int msgssz;
int msgtql;
unsigned short msgseg;
};
/*
* Scaling factor to compute msgmni:
* the memory dedicated to msg queues (msgmni * msgmnb) should occupy
* at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
* up to 8MB : msgmni = 16 (MSGMNI)
* 4 GB : msgmni = 8K
* more than 16 GB : msgmni = 32K (IPCMNI)
*/
#define MSG_MEM_SCALE 32
#define MSGMNI 16 /* <= IPCMNI */ /* max # of msg queue identifiers */
#define MSGMAX 8192 /* <= INT_MAX */ /* max size of message (bytes) */
#define MSGMNB 16384 /* <= INT_MAX */ /* default max size of a message queue */
/* unused */
#define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */
#define MSGTQL MSGMNB /* number of system message headers */
#define MSGMAP MSGMNB /* number of entries in message map */
#define MSGSSZ 16 /* message segment size */
#define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */
#define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
#ifdef __KERNEL__
#include <linux/list.h>
/* one msg_msg structure for each message */
struct msg_msg {
struct list_head m_list;
long m_type;
int m_ts; /* message text size */
struct msg_msgseg* next;
void *security;
/* the actual message follows immediately */
};
/* one msq_queue structure for each present queue on the system */
struct msg_queue {
struct kern_ipc_perm q_perm;
time_t q_stime; /* last msgsnd time */
time_t q_rtime; /* last msgrcv time */
time_t q_ctime; /* last change time */
unsigned long q_cbytes; /* current number of bytes on queue */
unsigned long q_qnum; /* number of messages in queue */
unsigned long q_qbytes; /* max number of bytes on queue */
pid_t q_lspid; /* pid of last msgsnd */
pid_t q_lrpid; /* last receive pid */
struct list_head q_messages;
struct list_head q_receivers;
struct list_head q_senders;
};
/* Helper routines for sys_msgsnd and sys_msgrcv */
extern long do_msgsnd(int msqid, long mtype, void __user *mtext,
size_t msgsz, int msgflg);
extern long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
size_t msgsz, long msgtyp, int msgflg);
#endif /* __KERNEL__ */
#endif /* _LINUX_MSG_H */