[PATCH 01/06]

This patch introduces ipcs storage into radix trees. The main changes are:
  . This ipc_ids structure is changed: the entries array is changed into a
    root radix_tree structure.
  . The grow_ary() routine is removed: it is not needed anymore when adding
    an ipc structure, due to radix trees introduction


Signed-off-by: Nadia Derbey <[EMAIL PROTECTED]>


---
 include/linux/ipc.h |    1 
 include/linux/msg.h |    1 
 include/linux/sem.h |    1 
 include/linux/shm.h |    1 
 ipc/msg.c           |   64 ++++++-------
 ipc/sem.c           |   63 ++++++------
 ipc/shm.c           |   63 ++++++------
 ipc/util.c          |  253 ++++++++++++++++++++++++++++------------------------
 ipc/util.h          |   30 +-----
 9 files changed, 248 insertions(+), 229 deletions(-)

Index: linux-2.6.21/ipc/util.h
===================================================================
--- linux-2.6.21.orig/ipc/util.h        2007-06-07 11:00:30.000000000 +0200
+++ linux-2.6.21/ipc/util.h     2007-06-07 11:07:22.000000000 +0200
@@ -13,6 +13,8 @@
 #define USHRT_MAX 0xffff
 #define SEQ_MULTIPLIER (IPCMNI)
 
+#define IPCS_MAX_SCAN_ENTRIES 256
+
 void sem_init (void);
 void msg_init (void);
 void shm_init (void);
@@ -25,19 +27,15 @@ void sem_exit_ns(struct ipc_namespace *n
 void msg_exit_ns(struct ipc_namespace *ns);
 void shm_exit_ns(struct ipc_namespace *ns);
 
-struct ipc_id_ary {
-       int size;
-       struct kern_ipc_perm *p[0];
-};
-
 struct ipc_ids {
        int in_use;
        int max_id;
+       int first_free;
        unsigned short seq;
        unsigned short seq_max;
        struct mutex mutex;
-       struct ipc_id_ary nullentry;
-       struct ipc_id_ary* entries;
+       struct radix_tree_root id_tree;
+       DECLARE_BITMAP(in_use_bitmap, IPCMNI);
 };
 
 struct seq_file;
@@ -46,7 +44,7 @@ struct seq_file;
 #else
 #define __ipc_init     __init
 #endif
-void __ipc_init ipc_init_ids(struct ipc_ids *ids, int size);
+void __ipc_init ipc_init_ids(struct ipc_ids *);
 #ifdef CONFIG_PROC_FS
 void __init ipc_init_proc_interface(const char *path, const char *header,
                int ids, int (*show)(struct seq_file *, void *));
@@ -59,8 +57,8 @@ void __init ipc_init_proc_interface(cons
 #define IPC_SHM_IDS    2
 
 /* must be called with ids->mutex acquired.*/
-int ipc_findkey(struct ipc_ids* ids, key_t key);
-int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
+struct kern_ipc_perm *ipc_findkey(struct ipc_ids *, key_t);
+int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
 
 /* must be called with both locks acquired. */
 struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
@@ -83,18 +81,6 @@ void* ipc_rcu_alloc(int size);
 void ipc_rcu_getref(void *ptr);
 void ipc_rcu_putref(void *ptr);
 
-static inline void __ipc_fini_ids(struct ipc_ids *ids,
-               struct ipc_id_ary *entries)
-{
-       if (entries != &ids->nullentry)
-               ipc_rcu_putref(entries);
-}
-
-static inline void ipc_fini_ids(struct ipc_ids *ids)
-{
-       __ipc_fini_ids(ids, ids->entries);
-}
-
 struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id);
 struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id);
 void ipc_lock_by_ptr(struct kern_ipc_perm *ipcp);
Index: linux-2.6.21/ipc/util.c
===================================================================
--- linux-2.6.21.orig/ipc/util.c        2007-06-07 11:00:30.000000000 +0200
+++ linux-2.6.21/ipc/util.c     2007-06-07 11:29:43.000000000 +0200
@@ -33,6 +33,7 @@
 #include <linux/proc_fs.h>
 #include <linux/audit.h>
 #include <linux/nsproxy.h>
+#include <linux/radix-tree.h>
 
 #include <asm/unistd.h>
 
@@ -51,6 +52,8 @@ struct ipc_namespace init_ipc_ns = {
        },
 };
 
+static void ipc_set_max_id(struct ipc_ids *);
+
 #ifdef CONFIG_IPC_NS
 static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
 {
@@ -172,23 +175,18 @@ __initcall(ipc_init);
 /**
  *     ipc_init_ids            -       initialise IPC identifiers
  *     @ids: Identifier set
- *     @size: Number of identifiers
  *
- *     Given a size for the ipc identifier range (limited below IPCMNI)
- *     set up the sequence range to use then allocate and initialise the
- *     array itself. 
+ *     Set up the sequence range to use for the ipc identifier range (limited
+ *     below IPCMNI) then initialise the ids radix tree.
  */
  
-void __ipc_init ipc_init_ids(struct ipc_ids* ids, int size)
+void __ipc_init ipc_init_ids(struct ipc_ids *ids)
 {
-       int i;
-
        mutex_init(&ids->mutex);
 
-       if(size > IPCMNI)
-               size = IPCMNI;
        ids->in_use = 0;
        ids->max_id = -1;
+       ids->first_free = 0;
        ids->seq = 0;
        {
                int seq_limit = INT_MAX/SEQ_MULTIPLIER;
@@ -198,17 +196,8 @@ void __ipc_init ipc_init_ids(struct ipc_
                        ids->seq_max = seq_limit;
        }
 
-       ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size +
-                                    sizeof(struct ipc_id_ary));
-
-       if(ids->entries == NULL) {
-               printk(KERN_ERR "ipc_init_ids() failed, ipc service 
disabled.\n");
-               size = 0;
-               ids->entries = &ids->nullentry;
-       }
-       ids->entries->size = size;
-       for(i=0;i<size;i++)
-               ids->entries->p[i] = NULL;
+       INIT_RADIX_TREE(&ids->id_tree, GFP_KERNEL);
+       bitmap_zero(ids->in_use_bitmap, IPCMNI);
 }
 
 #ifdef CONFIG_PROC_FS
@@ -252,72 +241,94 @@ void __init ipc_init_proc_interface(cons
  *     @key: The key to find
  *     
  *     Requires ipc_ids.mutex locked.
- *     Returns the identifier if found or -1 if not.
+ *     Returns the LOCKED pointer to the ipc structure if found or NULL
+ *     if not.
+ *      If key is found ipc contains its ipc structure
  */
  
-int ipc_findkey(struct ipc_ids* ids, key_t key)
+struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
 {
-       int id;
-       struct kern_ipc_perm* p;
-       int max_id = ids->max_id;
+       struct kern_ipc_perm *ipc;
+       struct kern_ipc_perm *ipcs[IPCS_MAX_SCAN_ENTRIES];
+       int next_id;
+       int nb_ipcs, i;
+       int total;
+
+       next_id = 0;
+       for (total = 0; total < ids->in_use; total += nb_ipcs) {
+               nb_ipcs = radix_tree_gang_lookup(&ids->id_tree,
+                       (void **) ipcs, next_id, IPCS_MAX_SCAN_ENTRIES);
+               if (nb_ipcs <= 0)
+                       return NULL;
+               for (i = 0; i < nb_ipcs; i++) {
+                       ipc = ipcs[i];
+                       if (ipc->key == key) {
+                               ipc_lock_by_ptr(ipc);
+                               BUG_ON(ipc->key != key);
+                               return ipc;
+                       }
+               }
 
-       /*
-        * rcu_dereference() is not needed here
-        * since ipc_ids.mutex is held
-        */
-       for (id = 0; id <= max_id; id++) {
-               p = ids->entries->p[id];
-               if(p==NULL)
-                       continue;
-               if (key == p->key)
-                       return id;
+               /* prepare for next id gang lookup */
+               next_id = (ipcs[nb_ipcs - 1]->id % SEQ_MULTIPLIER) + 1;
        }
-       return -1;
+
+       return NULL;
 }
 
-/*
- * Requires ipc_ids.mutex locked
+/**
+ *     ipc_set_max_id  -       set the last assigned id
+ *     @ids: IPC identifier set
+ *
+ *     Sets the new value for ids->max_id after max_id has been removed
+ *     during ipc_rmid().
+ *     When this routine is called ids->in_use has already been updated.
+ *
+ *     Called with ipc_ids.mutex held.
  */
-static int grow_ary(struct ipc_ids* ids, int newsize)
+
+static void ipc_set_max_id(struct ipc_ids *ids)
 {
-       struct ipc_id_ary* new;
-       struct ipc_id_ary* old;
-       int i;
-       int size = ids->entries->size;
-
-       if(newsize > IPCMNI)
-               newsize = IPCMNI;
-       if(newsize <= size)
-               return newsize;
-
-       new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize +
-                           sizeof(struct ipc_id_ary));
-       if(new == NULL)
-               return size;
-       new->size = newsize;
-       memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size);
-       for(i=size;i<newsize;i++) {
-               new->p[i] = NULL;
+       unsigned long next_bit;
+       unsigned long next_zero;
+
+
+       if (ids->in_use == 0) {
+               ids->max_id = -1;
+               return;
        }
-       old = ids->entries;
 
-       /*
-        * Use rcu_assign_pointer() to make sure the memcpyed contents
-        * of the new array are visible before the new array becomes visible.
-        */
-       rcu_assign_pointer(ids->entries, new);
+       if (ids->in_use == ids->max_id) {
+               /* No hole in the ids */
+               ids->max_id--;
+               return;
+       }
 
-       __ipc_fini_ids(ids, old);
-       return newsize;
+       /* Look for the last assigned id */
+       next_bit = find_first_bit(ids->in_use_bitmap, ids->max_id);
+
+       do {
+               next_zero = find_next_zero_bit(ids->in_use_bitmap,
+                                               ids->max_id, next_bit);
+               if (next_zero >= ids->max_id) {
+                       ids->max_id--;
+                       return;
+               } else
+                       next_bit = find_next_bit(ids->in_use_bitmap,
+                                       ids->max_id, next_zero);
+       } while (next_bit < ids->max_id);
+
+       ids->max_id = next_zero - 1;
+       return;
 }
 
 /**
  *     ipc_addid       -       add an IPC identifier
  *     @ids: IPC identifier set
  *     @new: new IPC permission set
- *     @size: new size limit for the id array
+ *     @size: limit for the number of used ids
  *
- *     Add an entry 'new' to the IPC arrays. The permissions object is
+ *     Add an entry 'new' to the IPC radix tree. The permissions object is
  *     initialised and the first free entry is set up and the id assigned
  *     is returned. The list is returned in a locked state on success.
  *     On failure the list is not locked and -1 is returned.
@@ -329,22 +340,33 @@ int ipc_addid(struct ipc_ids* ids, struc
 {
        int id;
 
-       size = grow_ary(ids,size);
-
        /*
         * rcu_dereference()() is not needed here since
         * ipc_ids.mutex is held
         */
-       for (id = 0; id < size; id++) {
-               if(ids->entries->p[id] == NULL)
-                       goto found;
-       }
-       return -1;
-found:
+       if (size > IPCMNI)
+               size = IPCMNI;
+
+       if (ids->in_use >= size)
+               return -1;
+
+       id = ids->first_free;
+
+       if (radix_tree_insert(&ids->id_tree, id, new))
+               return -1;
+
+       set_bit(id, ids->in_use_bitmap);
        ids->in_use++;
        if (id > ids->max_id)
                ids->max_id = id;
 
+       if (ids->in_use == ids->max_id + 1) {
+               /* No hole in the ids */
+               ids->first_free = ids->in_use;
+       } else
+               ids->first_free = find_next_zero_bit(ids->in_use_bitmap,
+                       ids->max_id, id);
+
        new->cuid = new->uid = current->euid;
        new->gid = new->cgid = current->egid;
 
@@ -356,7 +378,6 @@ found:
        new->deleted = 0;
        rcu_read_lock();
        spin_lock(&new->lock);
-       ids->entries->p[id] = new;
        return id;
 }
 
@@ -377,26 +398,27 @@ struct kern_ipc_perm* ipc_rmid(struct ip
 {
        struct kern_ipc_perm* p;
        int lid = id % SEQ_MULTIPLIER;
-       BUG_ON(lid >= ids->entries->size);
+       BUG_ON(lid > ids->max_id);
 
        /* 
         * do not need a rcu_dereference()() here to force ordering
         * on Alpha, since the ipc_ids.mutex is held.
         */     
-       p = ids->entries->p[lid];
-       ids->entries->p[lid] = NULL;
-       BUG_ON(p==NULL);
+       p = radix_tree_delete(&ids->id_tree, lid);
+       BUG_ON(p == NULL);
+
+       BUG_ON(ids->in_use <= 0);
        ids->in_use--;
 
-       if (lid == ids->max_id) {
-               do {
-                       lid--;
-                       if(lid == -1)
-                               break;
-               } while (ids->entries->p[lid] == NULL);
-               ids->max_id = lid;
-       }
+       clear_bit(lid, ids->in_use_bitmap);
+       if (lid < ids->first_free)
+               ids->first_free = lid;
+
+       if (lid == ids->max_id)
+               ipc_set_max_id(ids);
+
        p->deleted = 1;
+
        return p;
 }
 
@@ -492,6 +514,7 @@ static inline int rcu_use_vmalloc(int si
 void* ipc_rcu_alloc(int size)
 {
        void* out;
+
        /* 
         * We prepend the allocation with the rcu struct, and
         * workqueue if necessary (for vmalloc). 
@@ -660,9 +683,9 @@ struct kern_ipc_perm* ipc_get(struct ipc
 {
        struct kern_ipc_perm* out;
        int lid = id % SEQ_MULTIPLIER;
-       if(lid >= ids->entries->size)
+       if (lid > ids->max_id)
                return NULL;
-       out = ids->entries->p[lid];
+       out = radix_tree_lookup(&ids->id_tree, lid);
        return out;
 }
 
@@ -670,15 +693,13 @@ struct kern_ipc_perm* ipc_lock(struct ip
 {
        struct kern_ipc_perm* out;
        int lid = id % SEQ_MULTIPLIER;
-       struct ipc_id_ary* entries;
 
        rcu_read_lock();
-       entries = rcu_dereference(ids->entries);
-       if(lid >= entries->size) {
+       if (lid > ids->max_id) {
                rcu_read_unlock();
                return NULL;
        }
-       out = entries->p[lid];
+       out = radix_tree_lookup(&ids->id_tree, lid);
        if(out == NULL) {
                rcu_read_unlock();
                return NULL;
@@ -755,8 +776,9 @@ static void *sysvipc_proc_next(struct se
        struct ipc_proc_iter *iter = s->private;
        struct ipc_proc_iface *iface = iter->iface;
        struct kern_ipc_perm *ipc = it;
-       loff_t p;
        struct ipc_ids *ids;
+       struct kern_ipc_perm *ipcs[1];
+       int nb_ipcs;
 
        ids = iter->ns->ids[iface->ids];
 
@@ -764,19 +786,18 @@ static void *sysvipc_proc_next(struct se
        if (ipc && ipc != SEQ_START_TOKEN)
                ipc_unlock(ipc);
 
-       /*
-        * p = *pos - 1 (because id 0 starts at position 1)
-        *          + 1 (because we increment the position by one)
-        */
-       for (p = *pos; p <= ids->max_id; p++) {
-               if ((ipc = ipc_lock(ids, p)) != NULL) {
-                       *pos = p + 1;
-                       return ipc;
-               }
-       }
+       nb_ipcs = radix_tree_gang_lookup(&ids->id_tree, (void **) ipcs,
+                                       *pos, 1);
 
        /* Out of range - return NULL to terminate iteration */
-       return NULL;
+       if (nb_ipcs <= 0)
+               return NULL;
+
+       ipc = ipcs[0];
+       ipc_lock_by_ptr(ipc);
+       *pos = (ipc->id % SEQ_MULTIPLIER) + 1;
+
+       return ipc;
 }
 
 /*
@@ -788,8 +809,9 @@ static void *sysvipc_proc_start(struct s
        struct ipc_proc_iter *iter = s->private;
        struct ipc_proc_iface *iface = iter->iface;
        struct kern_ipc_perm *ipc;
-       loff_t p;
        struct ipc_ids *ids;
+       struct kern_ipc_perm *ipcs[1];
+       int nb_ipcs;
 
        ids = iter->ns->ids[iface->ids];
 
@@ -808,13 +830,16 @@ static void *sysvipc_proc_start(struct s
                return SEQ_START_TOKEN;
 
        /* Find the (pos-1)th ipc */
-       for (p = *pos - 1; p <= ids->max_id; p++) {
-               if ((ipc = ipc_lock(ids, p)) != NULL) {
-                       *pos = p + 1;
-                       return ipc;
-               }
-       }
-       return NULL;
+       nb_ipcs = radix_tree_gang_lookup(&ids->id_tree, (void **) ipcs,
+                                       *pos - 1, 1);
+       if (nb_ipcs <= 0)
+               return NULL;
+
+       ipc = ipcs[0];
+       ipc_lock_by_ptr(ipc);
+       *pos = (ipc->id % SEQ_MULTIPLIER) + 1;
+
+       return ipc;
 }
 
 static void sysvipc_proc_stop(struct seq_file *s, void *it)
Index: linux-2.6.21/ipc/msg.c
===================================================================
--- linux-2.6.21.orig/ipc/msg.c 2007-06-07 11:00:30.000000000 +0200
+++ linux-2.6.21/ipc/msg.c      2007-06-07 11:28:16.000000000 +0200
@@ -93,7 +93,7 @@ static void __ipc_init __msg_init_ns(str
        ns->msg_ctlmax = MSGMAX;
        ns->msg_ctlmnb = MSGMNB;
        ns->msg_ctlmni = MSGMNI;
-       ipc_init_ids(ids, ns->msg_ctlmni);
+       ipc_init_ids(ids);
 }
 
 #ifdef CONFIG_IPC_NS
@@ -124,7 +124,6 @@ void msg_exit_ns(struct ipc_namespace *n
        }
        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;
 }
@@ -164,7 +163,7 @@ static int newque (struct ipc_namespace 
                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;
@@ -175,7 +174,7 @@ static int newque (struct ipc_namespace 
        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)
@@ -227,9 +226,9 @@ static void expunge_all(struct msg_queue
 /*
  * 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.
+ * radix tree, 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)
@@ -257,7 +256,7 @@ static void freeque(struct ipc_namespace
 asmlinkage long sys_msgget(key_t key, int msgflg)
 {
        struct msg_queue *msq;
-       int id, ret = -EPERM;
+       int ret = -EPERM;
        struct ipc_namespace *ns;
 
        ns = current->nsproxy->ipc_ns;
@@ -265,26 +264,31 @@ asmlinkage long sys_msgget(key_t key, in
        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);
+       else  {
+               msq = (struct msg_queue *) ipc_findkey(&msg_ids(ns), key);
+               if (msq == NULL) {
+                       /* key not used */
+                       if (!(msgflg & IPC_CREAT))
+                               ret = -ENOENT;
+                       else
+                               ret = newque(ns, key, msgflg);
+               } else {
+                       /* msq has been locked by ipc_findkey() */
 
-                       ret = security_msg_queue_associate(msq, msgflg);
-                       if (!ret)
-                               ret = qid;
+                       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);
 
@@ -446,7 +450,7 @@ asmlinkage long sys_msgctl(int msqid, in
 
                if (!buf)
                        return -EFAULT;
-               if (cmd == MSG_STAT && msqid >= msg_ids(ns).entries->size)
+               if (cmd == MSG_STAT && msqid > msg_ids(ns).max_id)
                        return -EINVAL;
 
                memset(&tbuf, 0, sizeof(tbuf));
@@ -455,9 +459,9 @@ asmlinkage long sys_msgctl(int msqid, in
                if (msq == NULL)
                        return -EINVAL;
 
-               if (cmd == MSG_STAT) {
-                       success_return = msg_buildid(ns, msqid, 
msq->q_perm.seq);
-               } else {
+               if (cmd == MSG_STAT)
+                       success_return = msq->q_perm.id;
+               else {
                        err = -EIDRM;
                        if (msg_checkid(ns, msq, msqid))
                                goto out_unlock;
@@ -928,7 +932,7 @@ static int sysvipc_msg_proc_show(struct 
        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,
Index: linux-2.6.21/ipc/sem.c
===================================================================
--- linux-2.6.21.orig/ipc/sem.c 2007-06-07 11:00:30.000000000 +0200
+++ linux-2.6.21/ipc/sem.c      2007-06-07 11:25:20.000000000 +0200
@@ -130,7 +130,7 @@ static void __ipc_init __sem_init_ns(str
        ns->sc_semopm = SEMOPM;
        ns->sc_semmni = SEMMNI;
        ns->used_sems = 0;
-       ipc_init_ids(ids, ns->sc_semmni);
+       ipc_init_ids(ids);
 }
 
 #ifdef CONFIG_IPC_NS
@@ -161,7 +161,6 @@ void sem_exit_ns(struct ipc_namespace *n
        }
        mutex_unlock(&sem_ids(ns).mutex);
 
-       ipc_fini_ids(ns->ids[IPC_SEM_IDS]);
        kfree(ns->ids[IPC_SEM_IDS]);
        ns->ids[IPC_SEM_IDS] = NULL;
 }
@@ -246,7 +245,7 @@ static int newary (struct ipc_namespace 
        }
        ns->used_sems += nsems;
 
-       sma->sem_id = sem_buildid(ns, id, sma->sem_perm.seq);
+       sma->sem_perm.id = sem_buildid(ns, id, sma->sem_perm.seq);
        sma->sem_base = (struct sem *) &sma[1];
        /* sma->sem_pending = NULL; */
        sma->sem_pending_last = &sma->sem_pending;
@@ -255,12 +254,12 @@ static int newary (struct ipc_namespace 
        sma->sem_ctime = get_seconds();
        sem_unlock(sma);
 
-       return sma->sem_id;
+       return sma->sem_perm.id;
 }
 
 asmlinkage long sys_semget (key_t key, int nsems, int semflg)
 {
-       int id, err = -EINVAL;
+       int err = -EINVAL;
        struct sem_array *sma;
        struct ipc_namespace *ns;
 
@@ -272,27 +271,33 @@ asmlinkage long sys_semget (key_t key, i
        
        if (key == IPC_PRIVATE) {
                err = newary(ns, key, nsems, semflg);
-       } else if ((id = ipc_findkey(&sem_ids(ns), key)) == -1) {  /* key not 
used */
-               if (!(semflg & IPC_CREAT))
-                       err = -ENOENT;
-               else
-                       err = newary(ns, key, nsems, semflg);
-       } else if (semflg & IPC_CREAT && semflg & IPC_EXCL) {
-               err = -EEXIST;
        } else {
-               sma = sem_lock(ns, id);
-               BUG_ON(sma==NULL);
-               if (nsems > sma->sem_nsems)
-                       err = -EINVAL;
-               else if (ipcperms(&sma->sem_perm, semflg))
-                       err = -EACCES;
-               else {
-                       int semid = sem_buildid(ns, id, sma->sem_perm.seq);
-                       err = security_sem_associate(sma, semflg);
-                       if (!err)
-                               err = semid;
+               sma = (struct sem_array *) ipc_findkey(&sem_ids(ns), key);
+               if (sma == NULL) {
+                       /* key not used */
+                       if (!(semflg & IPC_CREAT))
+                               err = -ENOENT;
+                       else
+                               err = newary(ns, key, nsems, semflg);
+               } else {
+                       /* sma has been locked by ipc_findkey() */
+
+                       if (semflg & IPC_CREAT && semflg & IPC_EXCL)
+                               err = -EEXIST;
+                       else {
+                               if (nsems > sma->sem_nsems)
+                                       err = -EINVAL;
+                               else if (ipcperms(&sma->sem_perm, semflg))
+                                       err = -EACCES;
+                               else {
+                                       err = security_sem_associate(sma,
+                                                               semflg);
+                                       if (!err)
+                                               err = sma->sem_perm.id;
+                               }
+                       }
+                       sem_unlock(sma);
                }
-               sem_unlock(sma);
        }
 
        mutex_unlock(&sem_ids(ns).mutex);
@@ -498,7 +503,6 @@ static void freeary (struct ipc_namespac
 {
        struct sem_undo *un;
        struct sem_queue *q;
-       int size;
 
        /* Invalidate the existing undo structures for this semaphore set.
         * (They will be freed without any further action in exit_sem()
@@ -521,12 +525,11 @@ static void freeary (struct ipc_namespac
                q = n;
        }
 
-       /* Remove the semaphore set from the ID array*/
+       /* Remove the semaphore set from the ID radix tree */
        sma = sem_rmid(ns, id);
        sem_unlock(sma);
 
        ns->used_sems -= sma->sem_nsems;
-       size = sizeof (*sma) + sma->sem_nsems * sizeof (struct sem);
        security_sem_free(sma);
        ipc_rcu_putref(sma);
 }
@@ -598,7 +601,7 @@ static int semctl_nolock(struct ipc_name
                struct semid64_ds tbuf;
                int id;
 
-               if(semid >= sem_ids(ns).entries->size)
+               if (semid > sem_ids(ns).max_id)
                        return -EINVAL;
 
                memset(&tbuf,0,sizeof(tbuf));
@@ -615,7 +618,7 @@ static int semctl_nolock(struct ipc_name
                if (err)
                        goto out_unlock;
 
-               id = sem_buildid(ns, semid, sma->sem_perm.seq);
+               id = sma->sem_perm.id;
 
                kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
                tbuf.sem_otime  = sma->sem_otime;
@@ -1405,7 +1408,7 @@ static int sysvipc_sem_proc_show(struct 
        return seq_printf(s,
                          "%10d %10d  %4o %10lu %5u %5u %5u %5u %10lu %10lu\n",
                          sma->sem_perm.key,
-                         sma->sem_id,
+                         sma->sem_perm.id,
                          sma->sem_perm.mode,
                          sma->sem_nsems,
                          sma->sem_perm.uid,
Index: linux-2.6.21/ipc/shm.c
===================================================================
--- linux-2.6.21.orig/ipc/shm.c 2007-06-07 11:00:30.000000000 +0200
+++ linux-2.6.21/ipc/shm.c      2007-06-07 11:20:50.000000000 +0200
@@ -84,7 +84,7 @@ static void __ipc_init __shm_init_ns(str
        ns->shm_ctlall = SHMALL;
        ns->shm_ctlmni = SHMMNI;
        ns->shm_tot = 0;
-       ipc_init_ids(ids, 1);
+       ipc_init_ids(ids);
 }
 
 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
@@ -126,7 +126,6 @@ void shm_exit_ns(struct ipc_namespace *n
        }
        mutex_unlock(&shm_ids(ns).mutex);
 
-       ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
        kfree(ns->ids[IPC_SHM_IDS]);
        ns->ids[IPC_SHM_IDS] = NULL;
 }
@@ -186,7 +185,7 @@ static void shm_open(struct vm_area_stru
 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 {
        ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
-       shm_rmid(ns, shp->id);
+       shm_rmid(ns, shp->shm_perm.id);
        shm_unlock(shp);
        if (!is_file_hugepages(shp->shm_file))
                shmem_lock(shp->shm_file, 0, shp->mlock_user);
@@ -395,12 +394,13 @@ static int newseg (struct ipc_namespace 
        shp->shm_ctim = get_seconds();
        shp->shm_segsz = size;
        shp->shm_nattch = 0;
-       shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
+       shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
        shp->shm_file = file;
 
        ns->shm_tot += numpages;
+       error = shp->shm_perm.id;
        shm_unlock(shp);
-       return shp->id;
+       return error;
 
 no_id:
        fput(file);
@@ -413,7 +413,7 @@ no_file:
 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 {
        struct shmid_kernel *shp;
-       int err, id = 0;
+       int err;
        struct ipc_namespace *ns;
 
        ns = current->nsproxy->ipc_ns;
@@ -421,27 +421,32 @@ asmlinkage long sys_shmget (key_t key, s
        mutex_lock(&shm_ids(ns).mutex);
        if (key == IPC_PRIVATE) {
                err = newseg(ns, key, shmflg, size);
-       } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
-               if (!(shmflg & IPC_CREAT))
-                       err = -ENOENT;
-               else
-                       err = newseg(ns, key, shmflg, size);
-       } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
-               err = -EEXIST;
        } else {
-               shp = shm_lock(ns, id);
-               BUG_ON(shp==NULL);
-               if (shp->shm_segsz < size)
-                       err = -EINVAL;
-               else if (ipcperms(&shp->shm_perm, shmflg))
-                       err = -EACCES;
-               else {
-                       int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
-                       err = security_shm_associate(shp, shmflg);
-                       if (!err)
-                               err = shmid;
+               shp = (struct shmid_kernel *) ipc_findkey(&shm_ids(ns), key);
+               if (shp == NULL) {
+                       if (!(shmflg & IPC_CREAT))
+                               err = -ENOENT;
+                       else
+                               err = newseg(ns, key, shmflg, size);
+               } else {
+                       /* shp has been locked by ipc_findkey() */
+
+                       if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL))
+                               err = -EEXIST;
+                       else {
+                               if (shp->shm_segsz < size)
+                                       err = -EINVAL;
+                               else if (ipcperms(&shp->shm_perm, shmflg))
+                                       err = -EACCES;
+                               else {
+                                       err = security_shm_associate(shp,
+                                                               shmflg);
+                                       if (!err)
+                                               err = shp->shm_perm.id;
+                               }
+                       }
+                       shm_unlock(shp);
                }
-               shm_unlock(shp);
        }
        mutex_unlock(&shm_ids(ns).mutex);
 
@@ -645,9 +650,7 @@ asmlinkage long sys_shmctl (int shmid, i
                        goto out;
                } else if(cmd==SHM_STAT) {
                        err = -EINVAL;
-                       if (shmid > shm_ids(ns).max_id)
-                               goto out_unlock;
-                       result = shm_buildid(ns, shmid, shp->shm_perm.seq);
+                       result = shp->shm_perm.id;
                } else {
                        err = shm_checkid(ns, shp,shmid);
                        if(err)
@@ -919,7 +922,7 @@ long do_shmat(int shmid, char __user *sh
        file->f_path = path;
        file->f_mapping = shp->shm_file->f_mapping;
        file->f_mode = f_mode;
-       sfd->id = shp->id;
+       sfd->id = shp->shm_perm.id;
        sfd->ns = get_ipc_ns(ns);
        sfd->file = shp->shm_file;
        sfd->vm_ops = NULL;
@@ -1089,7 +1092,7 @@ static int sysvipc_shm_proc_show(struct 
                format = BIG_STRING;
        return seq_printf(s, format,
                          shp->shm_perm.key,
-                         shp->id,
+                         shp->shm_perm.id,
                          shp->shm_perm.mode,
                          shp->shm_segsz,
                          shp->shm_cprid,
Index: linux-2.6.21/include/linux/ipc.h
===================================================================
--- linux-2.6.21.orig/include/linux/ipc.h       2007-06-07 11:00:29.000000000 
+0200
+++ linux-2.6.21/include/linux/ipc.h    2007-06-07 11:14:20.000000000 +0200
@@ -60,6 +60,7 @@ struct kern_ipc_perm
 {
        spinlock_t      lock;
        int             deleted;
+       int             id;
        key_t           key;
        uid_t           uid;
        gid_t           gid;
Index: linux-2.6.21/include/linux/sem.h
===================================================================
--- linux-2.6.21.orig/include/linux/sem.h       2007-06-07 11:00:29.000000000 
+0200
+++ linux-2.6.21/include/linux/sem.h    2007-06-07 11:15:16.000000000 +0200
@@ -90,7 +90,6 @@ struct sem {
 /* One sem_array data structure for each set of semaphores in the system. */
 struct sem_array {
        struct kern_ipc_perm    sem_perm;       /* permissions .. see ipc.h */
-       int                     sem_id;
        time_t                  sem_otime;      /* last semop time */
        time_t                  sem_ctime;      /* last change time */
        struct sem              *sem_base;      /* ptr to first semaphore in 
array */
Index: linux-2.6.21/include/linux/shm.h
===================================================================
--- linux-2.6.21.orig/include/linux/shm.h       2007-06-07 11:00:29.000000000 
+0200
+++ linux-2.6.21/include/linux/shm.h    2007-06-07 11:16:06.000000000 +0200
@@ -77,7 +77,6 @@ struct shmid_kernel /* private to the ke
 {      
        struct kern_ipc_perm    shm_perm;
        struct file *           shm_file;
-       int                     id;
        unsigned long           shm_nattch;
        unsigned long           shm_segsz;
        time_t                  shm_atim;
Index: linux-2.6.21/include/linux/msg.h
===================================================================
--- linux-2.6.21.orig/include/linux/msg.h       2007-06-07 11:00:29.000000000 
+0200
+++ linux-2.6.21/include/linux/msg.h    2007-06-07 11:16:31.000000000 +0200
@@ -77,7 +77,6 @@ struct msg_msg {
 /* one msq_queue structure for each present queue on the system */
 struct msg_queue {
        struct kern_ipc_perm q_perm;
-       int q_id;
        time_t q_stime;                 /* last msgsnd time */
        time_t q_rtime;                 /* last msgrcv time */
        time_t q_ctime;                 /* last change time */

--
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