diff options
author | Nadia Derbey | 2008-04-29 01:00:45 -0700 |
---|---|---|
committer | Linus Torvalds | 2008-04-29 08:06:13 -0700 |
commit | 6546bc4279241e8fa432de1bb63a4f6f791fd669 (patch) | |
tree | 308f5c1621b1019a44800622ffc468a372f09434 /ipc | |
parent | 91cfb2b4b57816de0c96de417b3238249f0b125f (diff) |
ipc: re-enable msgmni automatic recomputing msgmni if set to negative
The enhancement as asked for by Yasunori: if msgmni is set to a negative
value, register it back into the ipcns notifier chain.
A new interface has been added to the notification mechanism:
notifier_chain_cond_register() registers a notifier block only if not already
registered. With that new interface we avoid taking care of the states
changes in procfs.
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>
Diffstat (limited to 'ipc')
-rw-r--r-- | ipc/ipc_sysctl.c | 45 | ||||
-rw-r--r-- | ipc/ipcns_notifier.c | 9 |
2 files changed, 44 insertions, 10 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index d12ff5cd2a0b..d3497465cc0a 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -15,6 +15,8 @@ #include <linux/sysctl.h> #include <linux/uaccess.h> #include <linux/ipc_namespace.h> +#include <linux/msg.h> +#include "util.h" static void *get_ipc(ctl_table *table) { @@ -24,6 +26,27 @@ static void *get_ipc(ctl_table *table) return which; } +/* + * Routine that is called when a tunable has successfully been changed by + * hand and it has a callback routine registered on the ipc namespace notifier + * chain: we don't want such tunables to be recomputed anymore upon memory + * add/remove or ipc namespace creation/removal. + * They can come back to a recomputable state by being set to a <0 value. + */ +static void tunable_set_callback(int val) +{ + if (val >= 0) + unregister_ipcns_notifier(current->nsproxy->ipc_ns); + else { + /* + * Re-enable automatic recomputing only if not already + * enabled. + */ + recompute_msgmni(current->nsproxy->ipc_ns); + cond_register_ipcns_notifier(current->nsproxy->ipc_ns); + } +} + #ifdef CONFIG_PROC_FS static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) @@ -38,17 +61,17 @@ static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp, static int proc_ipc_callback_dointvec(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) { + struct ctl_table ipc_table; size_t lenp_bef = *lenp; int rc; - rc = proc_ipc_dointvec(table, write, filp, buffer, lenp, ppos); + memcpy(&ipc_table, table, sizeof(ipc_table)); + ipc_table.data = get_ipc(table); + + rc = proc_dointvec(&ipc_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); + tunable_set_callback(*((int *)(ipc_table.data))); return rc; } @@ -119,12 +142,14 @@ static int sysctl_ipc_registered_data(ctl_table *table, int __user *name, rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval, newlen); - if (newval && newlen && rc > 0) + if (newval && newlen && rc > 0) { /* - * Tunable has successfully been changed from userland: - * disable its automatic recomputing. + * Tunable has successfully been changed from userland */ - unregister_ipcns_notifier(current->nsproxy->ipc_ns); + int *data = get_ipc(table); + + tunable_set_callback(*data); + } return rc; } diff --git a/ipc/ipcns_notifier.c b/ipc/ipcns_notifier.c index c7974609defc..70ff09183f7b 100644 --- a/ipc/ipcns_notifier.c +++ b/ipc/ipcns_notifier.c @@ -61,6 +61,15 @@ int register_ipcns_notifier(struct ipc_namespace *ns) return blocking_notifier_chain_register(&ipcns_chain, &ns->ipcns_nb); } +int cond_register_ipcns_notifier(struct ipc_namespace *ns) +{ + memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb)); + ns->ipcns_nb.notifier_call = ipcns_callback; + ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI; + return blocking_notifier_chain_cond_register(&ipcns_chain, + &ns->ipcns_nb); +} + int unregister_ipcns_notifier(struct ipc_namespace *ns) { return blocking_notifier_chain_unregister(&ipcns_chain, |