Blame view
ipc/ipcns_notifier.c
2.21 KB
b6b337ad1 ipc: recompute ms... |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
/* * linux/ipc/ipcns_notifier.c * Copyright (C) 2007 BULL SA. Nadia Derbey * * Notification mechanism for ipc namespaces: * The callback routine registered in the memory chain invokes the ipcns * notifier chain with the IPCNS_MEMCHANGED event. * Each callback routine registered in the ipcns namespace recomputes msgmni * for the owning namespace. */ #include <linux/msg.h> #include <linux/rcupdate.h> #include <linux/notifier.h> #include <linux/nsproxy.h> #include <linux/ipc_namespace.h> #include "util.h" static BLOCKING_NOTIFIER_HEAD(ipcns_chain); static int ipcns_callback(struct notifier_block *self, unsigned long action, void *arg) { struct ipc_namespace *ns; switch (action) { case IPCNS_MEMCHANGED: /* amount of lowmem has changed */ |
e2c284d8a ipc: recompute ms... |
32 33 |
case IPCNS_CREATED: case IPCNS_REMOVED: |
b6b337ad1 ipc: recompute ms... |
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 |
/* * It's time to recompute msgmni */ ns = container_of(self, struct ipc_namespace, ipcns_nb); /* * No need to get a reference on the ns: the 1st job of * free_ipc_ns() is to unregister the callback routine. * blocking_notifier_chain_unregister takes the wr lock to do * it. * When this callback routine is called the rd lock is held by * blocking_notifier_call_chain. * So the ipc ns cannot be freed while we are here. */ recompute_msgmni(ns); break; default: break; } return NOTIFY_OK; } int register_ipcns_notifier(struct ipc_namespace *ns) { |
9eefe520c ipc: do not use a... |
58 |
int rc; |
b6b337ad1 ipc: recompute ms... |
59 60 61 |
memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb)); ns->ipcns_nb.notifier_call = ipcns_callback; ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI; |
9eefe520c ipc: do not use a... |
62 63 64 65 |
rc = blocking_notifier_chain_register(&ipcns_chain, &ns->ipcns_nb); if (!rc) ns->auto_msgmni = 1; return rc; |
b6b337ad1 ipc: recompute ms... |
66 |
} |
6546bc427 ipc: re-enable ms... |
67 68 |
int cond_register_ipcns_notifier(struct ipc_namespace *ns) { |
9eefe520c ipc: do not use a... |
69 |
int rc; |
6546bc427 ipc: re-enable ms... |
70 71 72 |
memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb)); ns->ipcns_nb.notifier_call = ipcns_callback; ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI; |
9eefe520c ipc: do not use a... |
73 |
rc = blocking_notifier_chain_cond_register(&ipcns_chain, |
6546bc427 ipc: re-enable ms... |
74 |
&ns->ipcns_nb); |
9eefe520c ipc: do not use a... |
75 76 77 |
if (!rc) ns->auto_msgmni = 1; return rc; |
6546bc427 ipc: re-enable ms... |
78 |
} |
9eefe520c ipc: do not use a... |
79 |
void unregister_ipcns_notifier(struct ipc_namespace *ns) |
b6b337ad1 ipc: recompute ms... |
80 |
{ |
9eefe520c ipc: do not use a... |
81 82 |
blocking_notifier_chain_unregister(&ipcns_chain, &ns->ipcns_nb); ns->auto_msgmni = 0; |
b6b337ad1 ipc: recompute ms... |
83 84 85 86 87 88 |
} int ipcns_notify(unsigned long val) { return blocking_notifier_call_chain(&ipcns_chain, val, NULL); } |