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>
This commit is contained in:
Nadia Derbey
committed by
Linus Torvalds
Linus Torvalds
parent
d2b20b1154
commit
7ca7e564e0
262
ipc/util.c
262
ipc/util.c
@ -129,23 +129,16 @@ __initcall(ipc_init);
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/**
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* ipc_init_ids - initialise IPC identifiers
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* @ids: Identifier set
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* @size: Number of identifiers
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*
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* Given a size for the ipc identifier range (limited below IPCMNI)
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* set up the sequence range to use then allocate and initialise the
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* array itself.
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* Set up the sequence range to use for the ipc identifier range (limited
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* below IPCMNI) then initialise the ids idr.
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*/
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void ipc_init_ids(struct ipc_ids* ids, int size)
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void ipc_init_ids(struct ipc_ids *ids)
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{
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int i;
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mutex_init(&ids->mutex);
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if(size > IPCMNI)
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size = IPCMNI;
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ids->in_use = 0;
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ids->max_id = -1;
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ids->seq = 0;
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{
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int seq_limit = INT_MAX/SEQ_MULTIPLIER;
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@ -155,17 +148,7 @@ void ipc_init_ids(struct ipc_ids* ids, int size)
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ids->seq_max = seq_limit;
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}
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ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size +
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sizeof(struct ipc_id_ary));
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if(ids->entries == NULL) {
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printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n");
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size = 0;
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ids->entries = &ids->nullentry;
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}
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ids->entries->size = size;
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for(i=0;i<size;i++)
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ids->entries->p[i] = NULL;
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idr_init(&ids->ipcs_idr);
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}
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#ifdef CONFIG_PROC_FS
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@ -209,72 +192,73 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
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* @key: The key to find
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*
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* Requires ipc_ids.mutex locked.
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* Returns the identifier if found or -1 if not.
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* Returns the LOCKED pointer to the ipc structure if found or NULL
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* if not.
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* If key is found ipc contains its ipc structure
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*/
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int ipc_findkey(struct ipc_ids* ids, key_t key)
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struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
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{
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int id;
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struct kern_ipc_perm* p;
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int max_id = ids->max_id;
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struct kern_ipc_perm *ipc;
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int next_id;
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int total;
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/*
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* rcu_dereference() is not needed here
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* since ipc_ids.mutex is held
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*/
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for (id = 0; id <= max_id; id++) {
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p = ids->entries->p[id];
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if(p==NULL)
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for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
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ipc = idr_find(&ids->ipcs_idr, next_id);
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if (ipc == NULL)
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continue;
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if (key == p->key)
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return id;
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if (ipc->key != key) {
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total++;
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continue;
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}
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ipc_lock_by_ptr(ipc);
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return ipc;
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}
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return -1;
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return NULL;
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}
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/*
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* Requires ipc_ids.mutex locked
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/**
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* ipc_get_maxid - get the last assigned id
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* @ids: IPC identifier set
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*
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* Called with ipc_ids.mutex held.
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*/
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static int grow_ary(struct ipc_ids* ids, int newsize)
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int ipc_get_maxid(struct ipc_ids *ids)
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{
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struct ipc_id_ary* new;
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struct ipc_id_ary* old;
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int i;
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int size = ids->entries->size;
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struct kern_ipc_perm *ipc;
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int max_id = -1;
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int total, id;
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if(newsize > IPCMNI)
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newsize = IPCMNI;
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if(newsize <= size)
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return newsize;
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if (ids->in_use == 0)
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return -1;
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new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize +
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sizeof(struct ipc_id_ary));
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if(new == NULL)
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return size;
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new->size = newsize;
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memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size);
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for(i=size;i<newsize;i++) {
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new->p[i] = NULL;
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if (ids->in_use == IPCMNI)
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return IPCMNI - 1;
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/* Look for the last assigned id */
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total = 0;
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for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
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ipc = idr_find(&ids->ipcs_idr, id);
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if (ipc != NULL) {
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max_id = id;
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total++;
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}
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}
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old = ids->entries;
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/*
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* Use rcu_assign_pointer() to make sure the memcpyed contents
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* of the new array are visible before the new array becomes visible.
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*/
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rcu_assign_pointer(ids->entries, new);
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__ipc_fini_ids(ids, old);
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return newsize;
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return max_id;
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}
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/**
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* ipc_addid - add an IPC identifier
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* @ids: IPC identifier set
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* @new: new IPC permission set
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* @size: new size limit for the id array
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* @size: limit for the number of used ids
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*
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* Add an entry 'new' to the IPC arrays. The permissions object is
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* Add an entry 'new' to the IPC idr. The permissions object is
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* initialised and the first free entry is set up and the id assigned
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* is returned. The list is returned in a locked state on success.
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* On failure the list is not locked and -1 is returned.
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@ -284,23 +268,23 @@ static int grow_ary(struct ipc_ids* ids, int newsize)
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int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
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{
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int id;
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size = grow_ary(ids,size);
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int id, err;
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/*
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* rcu_dereference()() is not needed here since
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* ipc_ids.mutex is held
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*/
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for (id = 0; id < size; id++) {
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if(ids->entries->p[id] == NULL)
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goto found;
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}
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return -1;
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found:
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if (size > IPCMNI)
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size = IPCMNI;
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if (ids->in_use >= size)
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return -1;
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err = idr_get_new(&ids->ipcs_idr, new, &id);
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if (err)
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return -1;
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ids->in_use++;
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if (id > ids->max_id)
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ids->max_id = id;
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new->cuid = new->uid = current->euid;
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new->gid = new->cgid = current->egid;
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@ -313,48 +297,32 @@ found:
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new->deleted = 0;
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rcu_read_lock();
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spin_lock(&new->lock);
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ids->entries->p[id] = new;
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return id;
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}
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/**
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* ipc_rmid - remove an IPC identifier
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* @ids: identifier set
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* @id: Identifier to remove
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* @id: ipc perm structure containing the identifier to remove
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*
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* The identifier must be valid, and in use. The kernel will panic if
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* fed an invalid identifier. The entry is removed and internal
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* variables recomputed. The object associated with the identifier
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* is returned.
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* ipc_ids.mutex and the spinlock for this ID is hold before this function
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* is called, and remain locked on the exit.
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* variables recomputed.
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* ipc_ids.mutex and the spinlock for this ID are held before this
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* function is called, and remain locked on the exit.
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*/
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struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id)
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void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
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{
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struct kern_ipc_perm* p;
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int lid = id % SEQ_MULTIPLIER;
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BUG_ON(lid >= ids->entries->size);
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int lid = ipcp->id % SEQ_MULTIPLIER;
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idr_remove(&ids->ipcs_idr, lid);
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/*
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* do not need a rcu_dereference()() here to force ordering
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* on Alpha, since the ipc_ids.mutex is held.
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*/
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p = ids->entries->p[lid];
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ids->entries->p[lid] = NULL;
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BUG_ON(p==NULL);
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ids->in_use--;
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if (lid == ids->max_id) {
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do {
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lid--;
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if(lid == -1)
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break;
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} while (ids->entries->p[lid] == NULL);
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ids->max_id = lid;
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}
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p->deleted = 1;
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return p;
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ipcp->deleted = 1;
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return;
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}
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/**
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@ -613,33 +581,26 @@ void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
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* if in the future ipc_get() is used by other places without ipc_ids.mutex
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* down, then ipc_get() needs read memery barriers as ipc_lock() does.
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*/
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struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id)
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struct kern_ipc_perm *ipc_get(struct ipc_ids *ids, int id)
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{
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struct kern_ipc_perm* out;
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struct kern_ipc_perm *out;
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int lid = id % SEQ_MULTIPLIER;
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if(lid >= ids->entries->size)
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return NULL;
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out = ids->entries->p[lid];
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out = idr_find(&ids->ipcs_idr, lid);
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return out;
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}
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struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
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struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
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{
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struct kern_ipc_perm* out;
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struct kern_ipc_perm *out;
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int lid = id % SEQ_MULTIPLIER;
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struct ipc_id_ary* entries;
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rcu_read_lock();
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entries = rcu_dereference(ids->entries);
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if(lid >= entries->size) {
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rcu_read_unlock();
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return NULL;
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}
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out = entries->p[lid];
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if(out == NULL) {
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out = idr_find(&ids->ipcs_idr, lid);
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if (out == NULL) {
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rcu_read_unlock();
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return NULL;
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}
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spin_lock(&out->lock);
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/* ipc_rmid() may have already freed the ID while ipc_lock
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@ -650,6 +611,7 @@ struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
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rcu_read_unlock();
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return NULL;
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}
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return out;
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}
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@ -707,27 +669,30 @@ struct ipc_proc_iter {
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struct ipc_proc_iface *iface;
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};
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static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
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/*
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* This routine locks the ipc structure found at least at position pos.
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*/
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struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
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loff_t *new_pos)
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{
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struct ipc_proc_iter *iter = s->private;
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struct ipc_proc_iface *iface = iter->iface;
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struct kern_ipc_perm *ipc = it;
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loff_t p;
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struct ipc_ids *ids;
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struct kern_ipc_perm *ipc;
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int total, id;
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ids = iter->ns->ids[iface->ids];
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total = 0;
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for (id = 0; id < pos && total < ids->in_use; id++) {
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ipc = idr_find(&ids->ipcs_idr, id);
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if (ipc != NULL)
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total++;
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}
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/* If we had an ipc id locked before, unlock it */
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if (ipc && ipc != SEQ_START_TOKEN)
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ipc_unlock(ipc);
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if (total >= ids->in_use)
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return NULL;
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/*
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* p = *pos - 1 (because id 0 starts at position 1)
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* + 1 (because we increment the position by one)
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*/
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for (p = *pos; p <= ids->max_id; p++) {
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if ((ipc = ipc_lock(ids, p)) != NULL) {
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*pos = p + 1;
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for ( ; pos < IPCMNI; pos++) {
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ipc = idr_find(&ids->ipcs_idr, pos);
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if (ipc != NULL) {
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*new_pos = pos + 1;
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ipc_lock_by_ptr(ipc);
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return ipc;
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}
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}
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@ -736,6 +701,19 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
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return NULL;
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}
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static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
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{
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struct ipc_proc_iter *iter = s->private;
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struct ipc_proc_iface *iface = iter->iface;
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struct kern_ipc_perm *ipc = it;
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/* If we had an ipc id locked before, unlock it */
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if (ipc && ipc != SEQ_START_TOKEN)
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ipc_unlock(ipc);
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return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos);
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}
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/*
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* File positions: pos 0 -> header, pos n -> ipc id + 1.
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* SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START.
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@ -744,8 +722,6 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
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{
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struct ipc_proc_iter *iter = s->private;
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struct ipc_proc_iface *iface = iter->iface;
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struct kern_ipc_perm *ipc;
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loff_t p;
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struct ipc_ids *ids;
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ids = iter->ns->ids[iface->ids];
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@ -765,13 +741,7 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
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return SEQ_START_TOKEN;
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/* Find the (pos-1)th ipc */
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for (p = *pos - 1; p <= ids->max_id; p++) {
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if ((ipc = ipc_lock(ids, p)) != NULL) {
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*pos = p + 1;
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return ipc;
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}
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}
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return NULL;
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return sysvipc_find_ipc(ids, *pos - 1, pos);
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}
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static void sysvipc_proc_stop(struct seq_file *s, void *it)
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