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ipc: do not recompute msgmni anymore if explicitly set by user

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Make msgmni not recomputed anymore upon ipc namespace creation / removal or
memory add/remove, as soon as it has been set from userland.

As soon as msgmni is explicitly set via procfs or sysctl(), the associated
callback routine is unregistered from the ipc namespace notifier chain.

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nadia Derbey 2008-04-29 01:00:44 -07:00 committed by Linus Torvalds
parent e2c284d8a8
commit 91cfb2b4b5
1 changed files with 41 additions and 2 deletions
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43
ipc/ipc_sysctl.c
View file

@ -35,6 +35,24 @@ static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos); return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
} }
static int proc_ipc_callback_dointvec(ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
{
size_t lenp_bef = *lenp;
int rc;
rc = proc_ipc_dointvec(table, write, filp, buffer, lenp, ppos);
if (write && !rc && lenp_bef == *lenp)
/*
* Tunable has successfully been changed from userland:
* disable its automatic recomputing.
*/
unregister_ipcns_notifier(current->nsproxy->ipc_ns);
return rc;
}
static int proc_ipc_doulongvec_minmax(ctl_table *table, int write, static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
{ {
@ -49,6 +67,7 @@ static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
#else #else
#define proc_ipc_doulongvec_minmax NULL #define proc_ipc_doulongvec_minmax NULL
#define proc_ipc_dointvec NULL #define proc_ipc_dointvec NULL
#define proc_ipc_callback_dointvec NULL
#endif #endif
#ifdef CONFIG_SYSCTL_SYSCALL #ifdef CONFIG_SYSCTL_SYSCALL
@ -90,8 +109,28 @@ static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen,
} }
return 1; return 1;
} }
static int sysctl_ipc_registered_data(ctl_table *table, int __user *name,
int nlen, void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
int rc;
rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval,
newlen);
if (newval && newlen && rc > 0)
/*
* Tunable has successfully been changed from userland:
* disable its automatic recomputing.
*/
unregister_ipcns_notifier(current->nsproxy->ipc_ns);
return rc;
}
#else #else
#define sysctl_ipc_data NULL #define sysctl_ipc_data NULL
#define sysctl_ipc_registered_data NULL
#endif #endif
static struct ctl_table ipc_kern_table[] = { static struct ctl_table ipc_kern_table[] = {
@ -137,8 +176,8 @@ static struct ctl_table ipc_kern_table[] = {
.data = &init_ipc_ns.msg_ctlmni, .data = &init_ipc_ns.msg_ctlmni,
.maxlen = sizeof (init_ipc_ns.msg_ctlmni), .maxlen = sizeof (init_ipc_ns.msg_ctlmni),
.mode = 0644, .mode = 0644,
.proc_handler = proc_ipc_dointvec, .proc_handler = proc_ipc_callback_dointvec,
.strategy = sysctl_ipc_data, .strategy = sysctl_ipc_registered_data,
}, },
{ {
.ctl_name = KERN_MSGMNB, .ctl_name = KERN_MSGMNB,