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-rw-r--r--ipc/sem.c1
-rw-r--r--ipc/shm.c1
-rw-r--r--ipc/util.c97
-rw-r--r--ipc/util.h26
4 files changed, 75 insertions, 50 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index a5cff0e109ab..87bd38f38dc3 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -515,6 +515,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
sma->sem_nsems = nsems;
sma->sem_ctime = ktime_get_real_seconds();
+ /* ipc_addid() locks sma upon success. */
retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
if (retval < 0) {
call_rcu(&sma->sem_perm.rcu, sem_rcu_free);
diff --git a/ipc/shm.c b/ipc/shm.c
index 7733d768666d..7acda23430aa 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -601,6 +601,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
shp->shm_file = file;
shp->shm_creator = current;
+ /* ipc_addid() locks shp upon success. */
error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
if (error < 0)
goto no_id;
diff --git a/ipc/util.c b/ipc/util.c
index 79b30eee32cd..ff045fec8d83 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -116,13 +116,16 @@ int ipc_init_ids(struct ipc_ids *ids)
int err;
ids->in_use = 0;
ids->seq = 0;
- ids->next_id = -1;
init_rwsem(&ids->rwsem);
err = rhashtable_init(&ids->key_ht, &ipc_kht_params);
if (err)
return err;
idr_init(&ids->ipcs_idr);
ids->tables_initialized = true;
+ ids->max_id = -1;
+#ifdef CONFIG_CHECKPOINT_RESTORE
+ ids->next_id = -1;
+#endif
return 0;
}
@@ -186,41 +189,51 @@ static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
return NULL;
}
-/**
- * ipc_get_maxid - get the last assigned id
- * @ids: ipc identifier set
- *
- * Called with ipc_ids.rwsem held.
+#ifdef CONFIG_CHECKPOINT_RESTORE
+/*
+ * Specify desired id for next allocated IPC object.
*/
-int ipc_get_maxid(struct ipc_ids *ids)
+#define ipc_idr_alloc(ids, new) \
+ idr_alloc(&(ids)->ipcs_idr, (new), \
+ (ids)->next_id < 0 ? 0 : ipcid_to_idx((ids)->next_id),\
+ 0, GFP_NOWAIT)
+
+static inline int ipc_buildid(int id, struct ipc_ids *ids,
+ struct kern_ipc_perm *new)
{
- struct kern_ipc_perm *ipc;
- int max_id = -1;
- int total, id;
+ if (ids->next_id < 0) { /* default, behave as !CHECKPOINT_RESTORE */
+ new->seq = ids->seq++;
+ if (ids->seq > IPCID_SEQ_MAX)
+ ids->seq = 0;
+ } else {
+ new->seq = ipcid_to_seqx(ids->next_id);
+ ids->next_id = -1;
+ }
- if (ids->in_use == 0)
- return -1;
+ return SEQ_MULTIPLIER * new->seq + id;
+}
- if (ids->in_use == IPCMNI)
- return IPCMNI - 1;
+#else
+#define ipc_idr_alloc(ids, new) \
+ idr_alloc(&(ids)->ipcs_idr, (new), 0, 0, GFP_NOWAIT)
- /* Look for the last assigned id */
- total = 0;
- for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
- ipc = idr_find(&ids->ipcs_idr, id);
- if (ipc != NULL) {
- max_id = id;
- total++;
- }
- }
- return max_id;
+static inline int ipc_buildid(int id, struct ipc_ids *ids,
+ struct kern_ipc_perm *new)
+{
+ new->seq = ids->seq++;
+ if (ids->seq > IPCID_SEQ_MAX)
+ ids->seq = 0;
+
+ return SEQ_MULTIPLIER * new->seq + id;
}
+#endif /* CONFIG_CHECKPOINT_RESTORE */
+
/**
* ipc_addid - add an ipc identifier
* @ids: ipc identifier set
* @new: new ipc permission set
- * @size: limit for the number of used ids
+ * @limit: limit for the number of used ids
*
* Add an entry 'new' to the ipc ids idr. The permissions object is
* initialised and the first free entry is set up and the id assigned
@@ -229,17 +242,16 @@ int ipc_get_maxid(struct ipc_ids *ids)
*
* Called with writer ipc_ids.rwsem held.
*/
-int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
+int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
{
kuid_t euid;
kgid_t egid;
int id, err;
- int next_id = ids->next_id;
- if (size > IPCMNI)
- size = IPCMNI;
+ if (limit > IPCMNI)
+ limit = IPCMNI;
- if (!ids->tables_initialized || ids->in_use >= size)
+ if (!ids->tables_initialized || ids->in_use >= limit)
return -ENOSPC;
idr_preload(GFP_KERNEL);
@@ -254,9 +266,7 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
new->cuid = new->uid = euid;
new->gid = new->cgid = egid;
- id = idr_alloc(&ids->ipcs_idr, new,
- (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
- GFP_NOWAIT);
+ id = ipc_idr_alloc(ids, new);
idr_preload_end();
if (id >= 0 && new->key != IPC_PRIVATE) {
@@ -274,17 +284,11 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
}
ids->in_use++;
+ if (id > ids->max_id)
+ ids->max_id = id;
- if (next_id < 0) {
- new->seq = ids->seq++;
- if (ids->seq > IPCID_SEQ_MAX)
- ids->seq = 0;
- } else {
- new->seq = ipcid_to_seqx(next_id);
- ids->next_id = -1;
- }
+ new->id = ipc_buildid(id, ids, new);
- new->id = ipc_buildid(id, new->seq);
return id;
}
@@ -429,6 +433,15 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
ipc_kht_remove(ids, ipcp);
ids->in_use--;
ipcp->deleted = true;
+
+ if (unlikely(lid == ids->max_id)) {
+ do {
+ lid--;
+ if (lid == -1)
+ break;
+ } while (!idr_find(&ids->ipcs_idr, lid));
+ ids->max_id = lid;
+ }
}
/**
diff --git a/ipc/util.h b/ipc/util.h
index 579112d90016..89b8ec176fc4 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -13,6 +13,7 @@
#include <linux/unistd.h>
#include <linux/err.h>
+#include <linux/ipc_namespace.h>
#define SEQ_MULTIPLIER (IPCMNI)
@@ -99,9 +100,6 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
/* must be called with ids->rwsem acquired for writing */
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
-/* must be called with ids->rwsem acquired for reading */
-int ipc_get_maxid(struct ipc_ids *);
-
/* must be called with both locks acquired. */
void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
@@ -111,6 +109,23 @@ void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
/* must be called with ipcp locked */
int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
+/**
+ * ipc_get_maxid - get the last assigned id
+ * @ids: ipc identifier set
+ *
+ * Called with ipc_ids.rwsem held for reading.
+ */
+static inline int ipc_get_maxid(struct ipc_ids *ids)
+{
+ if (ids->in_use == 0)
+ return -1;
+
+ if (ids->in_use == IPCMNI)
+ return IPCMNI - 1;
+
+ return ids->max_id;
+}
+
/*
* For allocation that need to be freed by RCU.
* Objects are reference counted, they start with reference count 1.
@@ -146,11 +161,6 @@ extern struct msg_msg *load_msg(const void __user *src, size_t len);
extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
-static inline int ipc_buildid(int id, int seq)
-{
- return SEQ_MULTIPLIER * seq + id;
-}
-
static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
{
return uid / SEQ_MULTIPLIER != ipcp->seq;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 05:31:12 +0000