forked from Minki/linux
ipc,msg: introduce msgctl_nolock
Similar to semctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a msgctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). This change still takes the lock and it will be properly lockless in the next patch Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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parent
15724ecb7e
commit
2cafed30f1
49
ipc/msg.c
49
ipc/msg.c
@ -467,17 +467,11 @@ out_up:
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return err;
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}
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SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
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static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
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int cmd, int version, void __user *buf)
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{
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int err;
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struct msg_queue *msq;
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int err, version;
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struct ipc_namespace *ns;
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if (msqid < 0 || cmd < 0)
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return -EINVAL;
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version = ipc_parse_version(&cmd);
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ns = current->nsproxy->ipc_ns;
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switch (cmd) {
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case IPC_INFO:
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@ -488,6 +482,7 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
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if (!buf)
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return -EFAULT;
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/*
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* We must not return kernel stack data.
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* due to padding, it's not enough
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@ -519,7 +514,8 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
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return -EFAULT;
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return (max_id < 0) ? 0 : max_id;
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}
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case MSG_STAT: /* msqid is an index rather than a msg queue id */
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case MSG_STAT:
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case IPC_STAT:
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{
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struct msqid64_ds tbuf;
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@ -563,19 +559,42 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
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return -EFAULT;
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return success_return;
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}
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case IPC_SET:
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case IPC_RMID:
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err = msgctl_down(ns, msqid, cmd, buf, version);
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return err;
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default:
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return -EINVAL;
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return -EINVAL;
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}
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return err;
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out_unlock:
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msg_unlock(msq);
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return err;
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}
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SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
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{
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int version;
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struct ipc_namespace *ns;
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if (msqid < 0 || cmd < 0)
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return -EINVAL;
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version = ipc_parse_version(&cmd);
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ns = current->nsproxy->ipc_ns;
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switch (cmd) {
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case IPC_INFO:
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case MSG_INFO:
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case MSG_STAT: /* msqid is an index rather than a msg queue id */
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case IPC_STAT:
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return msgctl_nolock(ns, msqid, cmd, version, buf);
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case IPC_SET:
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case IPC_RMID:
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return msgctl_down(ns, msqid, cmd, buf, version);
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default:
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return -EINVAL;
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}
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}
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static int testmsg(struct msg_msg *msg, long type, int mode)
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{
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switch(mode)
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