ipc/util.c: further variable name cleanups

The varable names got a mess, thus standardize them again:

id: user space id. Called semid, shmid, msgid if the type is known.
    Most functions use "id" already.
idx: "index" for the idr lookup
    Right now, some functions use lid, ipc_addid() already uses idx as
    the variable name.
seq: sequence number, to avoid quick collisions of the user space id
key: user space key, used for the rhash tree

Link: http://lkml.kernel.org/r/20180712185241.4017-12-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/ipc_namespace.h

@@ -18,7 +18,7 @@ struct ipc_ids {
 	unsigned short seq;
 	struct rw_semaphore rwsem;
 	struct idr ipcs_idr;
-	int max_id;
+	int max_idx;
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	int next_id;
 #endif

ipc/msg.c

@@ -456,7 +456,7 @@ static int msgctl_info(struct ipc_namespace *ns, int msqid,
 			 int cmd, struct msginfo *msginfo)
 {
 	int err;
-	int max_id;
+	int max_idx;
 
 	/*
 	 * We must not return kernel stack data.
@@ -483,9 +483,9 @@ static int msgctl_info(struct ipc_namespace *ns, int msqid,
 		msginfo->msgpool = MSGPOOL;
 		msginfo->msgtql = MSGTQL;
 	}
-	max_id = ipc_get_maxid(&msg_ids(ns));
+	max_idx = ipc_get_maxidx(&msg_ids(ns));
 	up_read(&msg_ids(ns).rwsem);
-	return (max_id < 0) ? 0 : max_id;
+	return (max_idx < 0) ? 0 : max_idx;
 }
 
 static int msgctl_stat(struct ipc_namespace *ns, int msqid,

ipc/sem.c

@@ -1294,7 +1294,7 @@ static int semctl_info(struct ipc_namespace *ns, int semid,
 			 int cmd, void __user *p)
 {
 	struct seminfo seminfo;
-	int max_id;
+	int max_idx;
 	int err;
 
 	err = security_sem_semctl(NULL, cmd);
@@ -1318,11 +1318,11 @@ static int semctl_info(struct ipc_namespace *ns, int semid,
 		seminfo.semusz = SEMUSZ;
 		seminfo.semaem = SEMAEM;
 	}
-	max_id = ipc_get_maxid(&sem_ids(ns));
+	max_idx = ipc_get_maxidx(&sem_ids(ns));
 	up_read(&sem_ids(ns).rwsem);
 	if (copy_to_user(p, &seminfo, sizeof(struct seminfo)))
 		return -EFAULT;
-	return (max_id < 0) ? 0 : max_id;
+	return (max_idx < 0) ? 0 : max_idx;
 }
 
 static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,

ipc/shm.c

@@ -948,7 +948,7 @@ static int shmctl_ipc_info(struct ipc_namespace *ns,
 		shminfo->shmall = ns->shm_ctlall;
 		shminfo->shmmin = SHMMIN;
 		down_read(&shm_ids(ns).rwsem);
-		err = ipc_get_maxid(&shm_ids(ns));
+		err = ipc_get_maxidx(&shm_ids(ns));
 		up_read(&shm_ids(ns).rwsem);
 		if (err < 0)
 			err = 0;
@@ -968,7 +968,7 @@ static int shmctl_shm_info(struct ipc_namespace *ns,
 		shm_info->shm_tot = ns->shm_tot;
 		shm_info->swap_attempts = 0;
 		shm_info->swap_successes = 0;
-		err = ipc_get_maxid(&shm_ids(ns));
+		err = ipc_get_maxidx(&shm_ids(ns));
 		up_read(&shm_ids(ns).rwsem);
 		if (err < 0)
 			err = 0;

ipc/util.c

@@ -119,7 +119,7 @@ void ipc_init_ids(struct ipc_ids *ids)
 	init_rwsem(&ids->rwsem);
 	rhashtable_init(&ids->key_ht, &ipc_kht_params);
 	idr_init(&ids->ipcs_idr);
-	ids->max_id = -1;
+	ids->max_idx = -1;
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	ids->next_id = -1;
 #endif
@@ -237,7 +237,7 @@ static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
  * @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
+ * initialised and the first free entry is set up and the index assigned
  * is returned. The 'new' entry is returned in a locked state on success.
  *
  * On failure the entry is not locked and a negative err-code is returned.
@@ -291,8 +291,8 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
 	}
 
 	ids->in_use++;
-	if (idx > ids->max_id)
-		ids->max_id = idx;
+	if (idx > ids->max_idx)
+		ids->max_idx = idx;
 	return idx;
 }
 
@@ -431,20 +431,20 @@ static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
  */
 void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
 {
-	int lid = ipcid_to_idx(ipcp->id);
+	int idx = ipcid_to_idx(ipcp->id);
 
-	idr_remove(&ids->ipcs_idr, lid);
+	idr_remove(&ids->ipcs_idr, idx);
 	ipc_kht_remove(ids, ipcp);
 	ids->in_use--;
 	ipcp->deleted = true;
 
-	if (unlikely(lid == ids->max_id)) {
+	if (unlikely(idx == ids->max_idx)) {
 		do {
-			lid--;
-			if (lid == -1)
+			idx--;
+			if (idx == -1)
 				break;
-		} while (!idr_find(&ids->ipcs_idr, lid));
-		ids->max_id = lid;
+		} while (!idr_find(&ids->ipcs_idr, idx));
+		ids->max_idx = idx;
 	}
 }
 
@@ -564,9 +564,9 @@ void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out)
 struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id)
 {
 	struct kern_ipc_perm *out;
-	int lid = ipcid_to_idx(id);
+	int idx = ipcid_to_idx(id);
 
-	out = idr_find(&ids->ipcs_idr, lid);
+	out = idr_find(&ids->ipcs_idr, idx);
 	if (!out)
 		return ERR_PTR(-EINVAL);
 

ipc/util.h

@@ -113,20 +113,20 @@ void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
 int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
 
 /**
- * ipc_get_maxid - get the last assigned id
+ * ipc_get_maxidx - get the highest assigned index
  * @ids: ipc identifier set
  *
  * Called with ipc_ids.rwsem held for reading.
  */
-static inline int ipc_get_maxid(struct ipc_ids *ids)
+static inline int ipc_get_maxidx(struct ipc_ids *ids)
 {
 	if (ids->in_use == 0)
 		return -1;
 
 	if (ids->in_use == IPCMNI)
 		return IPCMNI - 1;
 
-	return ids->max_id;
+	return ids->max_idx;
 }
 
 /*
@@ -172,9 +172,9 @@ 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_checkid(struct kern_ipc_perm *ipcp, int uid)
+static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
 {
-	return uid / SEQ_MULTIPLIER != ipcp->seq;
+	return ipcid_to_seqx(id) != ipcp->seq;
 }
 
 static inline void ipc_lock_object(struct kern_ipc_perm *perm)