2.6.24

 ipc

diff --git a/ipc/msg.c b/ipc/msg.c
index a03fcb5..fdf3db5 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -34,7 +34,7 @@
 #include <linux/syscalls.h>
 #include <linux/audit.h>
 #include <linux/seq_file.h>
-#include <linux/mutex.h>
+#include <linux/rwsem.h>
 #include <linux/nsproxy.h>
 
 #include <asm/current.h>
@@ -66,23 +66,15 @@ struct msg_sender {
 #define SEARCH_NOTEQUAL      3
 #define SEARCH_LESSEQUAL   4
 
-static atomic_t msg_bytes =   ATOMIC_INIT(0);
-static atomic_t msg_hdrs =   ATOMIC_INIT(0);
-
 static struct ipc_ids init_msg_ids;
 
 #define msg_ids(ns)   (*((ns)->ids[IPC_MSG_IDS]))
 
-#define msg_lock(ns, id)   ((struct msg_queue*)ipc_lock(&msg_ids(ns), id))
 #define msg_unlock(msq)      ipc_unlock(&(msq)->q_perm)
-#define msg_rmid(ns, id)   ((struct msg_queue*)ipc_rmid(&msg_ids(ns), id))
-#define msg_checkid(ns, msq, msgid)   \
-   ipc_checkid(&msg_ids(ns), &msq->q_perm, msgid)
-#define msg_buildid(ns, id, seq) \
-   ipc_buildid(&msg_ids(ns), id, seq)
-
-static void freeque (struct ipc_namespace *ns, struct msg_queue *msq, int id);
-static int newque (struct ipc_namespace *ns, key_t key, int msgflg);
+#define msg_buildid(id, seq)   ipc_buildid(id, seq)
+
+static void freeque(struct ipc_namespace *, struct msg_queue *);
+static int newque(struct ipc_namespace *, struct ipc_params *);
 #ifdef CONFIG_PROC_FS
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif
@@ -93,7 +85,9 @@ static void __msg_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
    ns->msg_ctlmax = MSGMAX;
    ns->msg_ctlmnb = MSGMNB;
    ns->msg_ctlmni = MSGMNI;
-   ipc_init_ids(ids, ns->msg_ctlmni);
+   atomic_set(&ns->msg_bytes, 0);
+   atomic_set(&ns->msg_hdrs, 0);
+   ipc_init_ids(ids);
 }
 
 int msg_init_ns(struct ipc_namespace *ns)
@@ -110,20 +104,25 @@ int msg_init_ns(struct ipc_namespace *ns)
 
 void msg_exit_ns(struct ipc_namespace *ns)
 {
-   int i;
    struct msg_queue *msq;
+   int next_id;
+   int total, in_use;
+
+   down_write(&msg_ids(ns).rw_mutex);
+
+   in_use = msg_ids(ns).in_use;
 
-   mutex_lock(&msg_ids(ns).mutex);
-   for (i = 0; i <= msg_ids(ns).max_id; i++) {
-      msq = msg_lock(ns, i);
+   for (total = 0, next_id = 0; total < in_use; next_id++) {
+      msq = idr_find(&msg_ids(ns).ipcs_idr, next_id);
       if (msq == NULL)
          continue;
-
-      freeque(ns, msq, i);
+      ipc_lock_by_ptr(&msq->q_perm);
+      freeque(ns, msq);
+      total++;
    }
-   mutex_unlock(&msg_ids(ns).mutex);
 
-   ipc_fini_ids(ns->ids[IPC_MSG_IDS]);
+   up_write(&msg_ids(ns).rw_mutex);
+
    kfree(ns->ids[IPC_MSG_IDS]);
    ns->ids[IPC_MSG_IDS] = NULL;
 }
@@ -136,10 +135,55 @@ void __init msg_init(void)
             IPC_MSG_IDS, sysvipc_msg_proc_show);
 }
 
-static int newque (struct ipc_namespace *ns, key_t key, int msgflg)
+/*
+ * This routine is called in the paths where the rw_mutex is held to protect
+ * access to the idr tree.
+ */
+static inline struct msg_queue *msg_lock_check_down(struct ipc_namespace *ns,
+                  int id)
+{
+   struct kern_ipc_perm *ipcp = ipc_lock_check_down(&msg_ids(ns), id);
+
+   return container_of(ipcp, struct msg_queue, q_perm);
+}
+
+/*
+ * msg_lock_(check_) routines are called in the paths where the rw_mutex
+ * is not held.
+ */
+static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
+{
+   struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
+
+   return container_of(ipcp, struct msg_queue, q_perm);
+}
+
+static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
+                  int id)
+{
+   struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
+
+   return container_of(ipcp, struct msg_queue, q_perm);
+}
+
+static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
+{
+   ipc_rmid(&msg_ids(ns), &s->q_perm);
+}
+
+/**
+ * newque - Create a new msg queue
+ * @ns: namespace
+ * @params: ptr to the structure that contains the key and msgflg
+ *
+ * Called with msg_ids.rw_mutex held (writer)
+ */
+static int newque(struct ipc_namespace *ns, struct ipc_params *params)
 {
    struct msg_queue *msq;
    int id, retval;
+   key_t key = params->key;
+   int msgflg = params->flg;
 
    msq = ipc_rcu_alloc(sizeof(*msq));
    if (!msq)
@@ -155,14 +199,17 @@ static int newque (struct ipc_namespace *ns, key_t key, int msgflg)
       return retval;
    }
 
+   /*
+    * ipc_addid() locks msq
+    */
    id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
-   if (id == -1) {
+   if (id < 0) {
       security_msg_queue_free(msq);
       ipc_rcu_putref(msq);
-      return -ENOSPC;
+      return id;
    }
 
-   msq->q_id = msg_buildid(ns, id, msq->q_perm.seq);
+   msq->q_perm.id = msg_buildid(id, msq->q_perm.seq);
    msq->q_stime = msq->q_rtime = 0;
    msq->q_ctime = get_seconds();
    msq->q_cbytes = msq->q_qnum = 0;
@@ -171,9 +218,10 @@ static int newque (struct ipc_namespace *ns, key_t key, int msgflg)
    INIT_LIST_HEAD(&msq->q_messages);
    INIT_LIST_HEAD(&msq->q_receivers);
    INIT_LIST_HEAD(&msq->q_senders);
+
    msg_unlock(msq);
 
-   return msq->q_id;
+   return msq->q_perm.id;
 }
 
 static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
@@ -224,19 +272,19 @@ static void expunge_all(struct msg_queue *msq, int res)
 
 /*
  * freeque() wakes up waiters on the sender and receiver waiting queue,
- * removes the message queue from message queue ID
- * array, and cleans up all the messages associated with this queue.
+ * removes the message queue from message queue ID IDR, and cleans up all the
+ * messages associated with this queue.
  *
- * msg_ids.mutex and the spinlock for this message queue is hold
- * before freeque() is called. msg_ids.mutex remains locked on exit.
+ * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
+ * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
  */
-static void freeque(struct ipc_namespace *ns, struct msg_queue *msq, int id)
+static void freeque(struct ipc_namespace *ns, struct msg_queue *msq)
 {
    struct list_head *tmp;
 
    expunge_all(msq, -EIDRM);
    ss_wakeup(&msq->q_senders, 1);
-   msq = msg_rmid(ns, id);
+   msg_rmid(ns, msq);
    msg_unlock(msq);
 
    tmp = msq->q_messages.next;
@@ -244,49 +292,40 @@ static void freeque(struct ipc_namespace *ns, struct msg_queue *msq, int id)
       struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list);
 
       tmp = tmp->next;
-      atomic_dec(&msg_hdrs);
+      atomic_dec(&ns->msg_hdrs);
       free_msg(msg);
    }
-   atomic_sub(msq->q_cbytes, &msg_bytes);
+   atomic_sub(msq->q_cbytes, &ns->msg_bytes);
    security_msg_queue_free(msq);
    ipc_rcu_putref(msq);
 }
 
+/*
+ * Called with msg_ids.rw_mutex and ipcp locked.
+ */
+static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
+{
+   struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
+
+   return security_msg_queue_associate(msq, msgflg);
+}
+
 asmlinkage long sys_msgget(key_t key, int msgflg)
 {
-   struct msg_queue *msq;
-   int id, ret = -EPERM;
    struct ipc_namespace *ns;
+   struct ipc_ops msg_ops;
+   struct ipc_params msg_params;
 
    ns = current->nsproxy->ipc_ns;
-   
-   mutex_lock(&msg_ids(ns).mutex);
-   if (key == IPC_PRIVATE) 
-      ret = newque(ns, key, msgflg);
-   else if ((id = ipc_findkey(&msg_ids(ns), key)) == -1) { /* key not used */
-      if (!(msgflg & IPC_CREAT))
-         ret = -ENOENT;
-      else
-         ret = newque(ns, key, msgflg);
-   } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) {
-      ret = -EEXIST;
-   } else {
-      msq = msg_lock(ns, id);
-      BUG_ON(msq == NULL);
-      if (ipcperms(&msq->q_perm, msgflg))
-         ret = -EACCES;
-      else {
-         int qid = msg_buildid(ns, id, msq->q_perm.seq);
-
-         ret = security_msg_queue_associate(msq, msgflg);
-         if (!ret)
-            ret = qid;
-      }
-      msg_unlock(msq);
-   }
-   mutex_unlock(&msg_ids(ns).mutex);
 
-   return ret;
+   msg_ops.getnew = newque;
+   msg_ops.associate = msg_security;
+   msg_ops.more_checks = NULL;
+
+   msg_params.key = key;
+   msg_params.flg = msgflg;
+
+   return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
 }
 
 static inline unsigned long
@@ -420,23 +459,23 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
       msginfo.msgmnb = ns->msg_ctlmnb;
       msginfo.msgssz = MSGSSZ;
       msginfo.msgseg = MSGSEG;
-      mutex_lock(&msg_ids(ns).mutex);
+      down_read(&msg_ids(ns).rw_mutex);
       if (cmd == MSG_INFO) {
          msginfo.msgpool = msg_ids(ns).in_use;
-         msginfo.msgmap = atomic_read(&msg_hdrs);
-         msginfo.msgtql = atomic_read(&msg_bytes);
+         msginfo.msgmap = atomic_read(&ns->msg_hdrs);
+         msginfo.msgtql = atomic_read(&ns->msg_bytes);
       } else {
          msginfo.msgmap = MSGMAP;
          msginfo.msgpool = MSGPOOL;
          msginfo.msgtql = MSGTQL;
       }
-      max_id = msg_ids(ns).max_id;
-      mutex_unlock(&msg_ids(ns).mutex);
+      max_id = ipc_get_maxid(&msg_ids(ns));
+      up_read(&msg_ids(ns).rw_mutex);
       if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
          return -EFAULT;
       return (max_id < 0) ? 0 : max_id;
    }
-   case MSG_STAT:
+   case MSG_STAT:   /* msqid is an index rather than a msg queue id */
    case IPC_STAT:
    {
       struct msqid64_ds tbuf;
@@ -444,21 +483,16 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
 
       if (!buf)
          return -EFAULT;
-      if (cmd == MSG_STAT && msqid >= msg_ids(ns).entries->size)
-         return -EINVAL;
-
-      memset(&tbuf, 0, sizeof(tbuf));
-
-      msq = msg_lock(ns, msqid);
-      if (msq == NULL)
-         return -EINVAL;
 
       if (cmd == MSG_STAT) {
-         success_return = msg_buildid(ns, msqid, msq->q_perm.seq);
+         msq = msg_lock(ns, msqid);
+         if (IS_ERR(msq))
+            return PTR_ERR(msq);
+         success_return = msq->q_perm.id;
       } else {
-         err = -EIDRM;
-         if (msg_checkid(ns, msq, msqid))
-            goto out_unlock;
+         msq = msg_lock_check(ns, msqid);
+         if (IS_ERR(msq))
+            return PTR_ERR(msq);
          success_return = 0;
       }
       err = -EACCES;
@@ -469,6 +503,8 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
       if (err)
          goto out_unlock;
 
+      memset(&tbuf, 0, sizeof(tbuf));
+
       kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
       tbuf.msg_stime  = msq->q_stime;
       tbuf.msg_rtime  = msq->q_rtime;
@@ -495,15 +531,13 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
       return  -EINVAL;
    }
 
-   mutex_lock(&msg_ids(ns).mutex);
-   msq = msg_lock(ns, msqid);
-   err = -EINVAL;
-   if (msq == NULL)
+   down_write(&msg_ids(ns).rw_mutex);
+   msq = msg_lock_check_down(ns, msqid);
+   if (IS_ERR(msq)) {
+      err = PTR_ERR(msq);
       goto out_up;
+   }
 
-   err = -EIDRM;
-   if (msg_checkid(ns, msq, msqid))
-      goto out_unlock_up;
    ipcp = &msq->q_perm;
 
    err = audit_ipc_obj(ipcp);
@@ -552,12 +586,12 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
       break;
    }
    case IPC_RMID:
-      freeque(ns, msq, msqid);
+      freeque(ns, msq);
       break;
    }
    err = 0;
 out_up:
-   mutex_unlock(&msg_ids(ns).mutex);
+   up_write(&msg_ids(ns).rw_mutex);
    return err;
 out_unlock_up:
    msg_unlock(msq);
@@ -611,7 +645,7 @@ static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
             msr->r_msg = ERR_PTR(-E2BIG);
          } else {
             msr->r_msg = NULL;
-            msq->q_lrpid = msr->r_tsk->pid;
+            msq->q_lrpid = task_pid_vnr(msr->r_tsk);
             msq->q_rtime = get_seconds();
             wake_up_process(msr->r_tsk);
             smp_mb();
@@ -646,14 +680,11 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
    msg->m_type = mtype;
    msg->m_ts = msgsz;
 
-   msq = msg_lock(ns, msqid);
-   err = -EINVAL;
-   if (msq == NULL)
+   msq = msg_lock_check(ns, msqid);
+   if (IS_ERR(msq)) {
+      err = PTR_ERR(msq);
       goto out_free;
-
-   err= -EIDRM;
-   if (msg_checkid(ns, msq, msqid))
-      goto out_unlock_free;
+   }
 
    for (;;) {
       struct msg_sender s;
@@ -695,7 +726,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
       }
    }
 
-   msq->q_lspid = current->tgid;
+   msq->q_lspid = task_tgid_vnr(current);
    msq->q_stime = get_seconds();
 
    if (!pipelined_send(msq, msg)) {
@@ -703,8 +734,8 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
       list_add_tail(&msg->m_list, &msq->q_messages);
       msq->q_cbytes += msgsz;
       msq->q_qnum++;
-      atomic_add(msgsz, &msg_bytes);
-      atomic_inc(&msg_hdrs);
+      atomic_add(msgsz, &ns->msg_bytes);
+      atomic_inc(&ns->msg_hdrs);
    }
 
    err = 0;
@@ -760,13 +791,9 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
    mode = convert_mode(&msgtyp, msgflg);
    ns = current->nsproxy->ipc_ns;
 
-   msq = msg_lock(ns, msqid);
-   if (msq == NULL)
-      return -EINVAL;
-
-   msg = ERR_PTR(-EIDRM);
-   if (msg_checkid(ns, msq, msqid))
-      goto out_unlock;
+   msq = msg_lock_check(ns, msqid);
+   if (IS_ERR(msq))
+      return PTR_ERR(msq);
 
    for (;;) {
       struct msg_receiver msr_d;
@@ -810,10 +837,10 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
          list_del(&msg->m_list);
          msq->q_qnum--;
          msq->q_rtime = get_seconds();
-         msq->q_lrpid = current->tgid;
+         msq->q_lrpid = task_tgid_vnr(current);
          msq->q_cbytes -= msg->m_ts;
-         atomic_sub(msg->m_ts, &msg_bytes);
-         atomic_dec(&msg_hdrs);
+         atomic_sub(msg->m_ts, &ns->msg_bytes);
+         atomic_dec(&ns->msg_hdrs);
          ss_wakeup(&msq->q_senders, 0);
          msg_unlock(msq);
          break;
@@ -926,7 +953,7 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
    return seq_printf(s,
          "%10d %10d  %4o  %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
          msq->q_perm.key,
-         msq->q_id,
+         msq->q_perm.id,
          msq->q_perm.mode,
          msq->q_cbytes,
          msq->q_qnum,