ipc: store ipcs into IDRs

This patch introduces ipcs storage into IDRs. The main changes are:
  . This ipc_ids structure is changed: the entries array is changed into a
    root idr structure.
  . The grow_ary() routine is removed: it is not needed anymore when adding
    an ipc structure, since we are now using the IDR facility.
  . The ipc_rmid() routine interface is changed:
       . there is no need for this routine to return the pointer passed in as
         argument: it is now declared as a void
       . since the id is now part of the kern_ipc_perm structure, no need to
         have it as an argument to the routine

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 70 insertions, 45 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index 319468609b76..08591a0278ce 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -75,13 +75,12 @@ static struct ipc_ids init_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 void freeque(struct ipc_namespace *, struct msg_queue *);
 static int newque (struct ipc_namespace *ns, key_t key, int msgflg);
 #ifdef CONFIG_PROC_FS
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
@@ -93,7 +92,7 @@ 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);
+        ipc_init_ids(ids);
 }
 
 int msg_init_ns(struct ipc_namespace *ns)
@@ -110,20 +109,24 @@ 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;
 
         mutex_lock(&msg_ids(ns).mutex);
-        for (i = 0; i <= msg_ids(ns).max_id; i++) {
-                msq = msg_lock(ns, i);
+
+        in_use = msg_ids(ns).in_use;
+
+        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]);
         kfree(ns->ids[IPC_MSG_IDS]);
         ns->ids[IPC_MSG_IDS] = NULL;
 }
@@ -136,6 +139,11 @@ void __init msg_init(void)
                                 IPC_MSG_IDS, sysvipc_msg_proc_show);
 }
 
+static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
+{
+        ipc_rmid(&msg_ids(ns), &s->q_perm);
+}
+
 static int newque (struct ipc_namespace *ns, key_t key, int msgflg)
 {
         struct msg_queue *msq;
@@ -155,6 +163,9 @@ 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) {
                 security_msg_queue_free(msq);
@@ -162,7 +173,7 @@ static int newque (struct ipc_namespace *ns, key_t key, int msgflg)
                 return -ENOSPC;
         }
 
-        msq->q_id = msg_buildid(ns, id, msq->q_perm.seq);
+        msq->q_perm.id = msg_buildid(ns, 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 +182,10 @@ 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)
@@ -225,18 +237,18 @@ 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.
+ * IDR, and cleans up all the messages associated with this queue.
  *
- * msg_ids.mutex and the spinlock for this message queue is hold
+ * msg_ids.mutex and the spinlock for this message queue are held
  * before freeque() is called. msg_ids.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;
@@ -255,36 +267,51 @@ static void freeque(struct ipc_namespace *ns, struct msg_queue *msq, int id)
 asmlinkage long sys_msgget(key_t key, int msgflg)
 {
         struct msg_queue *msq;
-        int id, ret = -EPERM;
+        int ret;
         struct ipc_namespace *ns;
 
         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 = idr_pre_get(&msg_ids(ns).ipcs_idr, GFP_KERNEL);
+
+        if (key == IPC_PRIVATE)  {
+                if (!ret)
+                        ret = -ENOMEM;
+                else {
+                        mutex_lock(&msg_ids(ns).mutex);
                         ret = newque(ns, key, msgflg);
-        } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) {
-                ret = -EEXIST;
+                        mutex_unlock(&msg_ids(ns).mutex);
+                }
         } 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;
+                mutex_lock(&msg_ids(ns).mutex);
+                msq = (struct msg_queue *) ipc_findkey(&msg_ids(ns), key);
+                if (msq == NULL) {
+                        /* key not used */
+                        if (!(msgflg & IPC_CREAT))
+                                ret = -ENOENT;
+                        else if (!ret)
+                                ret = -ENOMEM;
+                        else
+                                ret = newque(ns, key, msgflg);
+                } else {
+                        /* msq has been locked by ipc_findkey() */
+
+                        if (msgflg & IPC_CREAT && msgflg & IPC_EXCL)
+                                ret = -EEXIST;
+                        else {
+                                if (ipcperms(&msq->q_perm, msgflg))
+                                        ret = -EACCES;
+                                else {
+                                        ret = security_msg_queue_associate(
+                                                                msq, msgflg);
+                                        if (!ret)
+                                                ret = msq->q_perm.id;
+                                }
+                        }
+                        msg_unlock(msq);
                 }
-                msg_unlock(msq);
+                mutex_unlock(&msg_ids(ns).mutex);
         }
-        mutex_unlock(&msg_ids(ns).mutex);
 
         return ret;
 }
@@ -430,13 +457,13 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
                         msginfo.msgpool = MSGPOOL;
                         msginfo.msgtql = MSGTQL;
                 }
-                max_id = msg_ids(ns).max_id;
+                max_id = ipc_get_maxid(&msg_ids(ns));
                 mutex_unlock(&msg_ids(ns).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;
@@ -444,8 +471,6 @@ 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));
 
@@ -454,7 +479,7 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
                         return -EINVAL;
 
                 if (cmd == MSG_STAT) {
-                        success_return = msg_buildid(ns, msqid, msq->q_perm.seq);
+                        success_return = msq->q_perm.id;
                 } else {
                         err = -EIDRM;
                         if (msg_checkid(ns, msq, msqid))
@@ -552,7 +577,7 @@ 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;
@@ -926,7 +951,7 @@ 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,