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Subject[patch 1/3] ipc: rename IPCMNI to IPCMNI_MAX
Hi,

Just a couple of small IPC patches I have, I wonder if you could
comment on or merge?

--
The IPCMNI limit is different from the other MNI limits. It is not exposed
to userspace, it is not tunable via sysctl -- it is a hard limit. Rename it
to IPCMNI_MAX, to signify it is a maximum rather than default value.

It is an internal value tied to IPC sequence numbering, so move it into
ipc/util.h.

Index: linux-2.6/include/linux/ipc.h
===================================================================
--- linux-2.6.orig/include/linux/ipc.h
+++ linux-2.6/include/linux/ipc.h
@@ -80,8 +80,6 @@ struct ipc_kludge {
#ifdef __KERNEL__
#include <linux/spinlock.h>

-#define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
-
/* used by in-kernel data structures */
struct kern_ipc_perm
{
Index: linux-2.6/include/linux/msg.h
===================================================================
--- linux-2.6.orig/include/linux/msg.h
+++ linux-2.6/include/linux/msg.h
@@ -55,11 +55,11 @@ struct msginfo {
* at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
* up to 8MB : msgmni = 16 (MSGMNI)
* 4 GB : msgmni = 8K
- * more than 16 GB : msgmni = 32K (IPCMNI)
+ * more than 16 GB : msgmni = 32K (IPCMNI_MAX)
*/
#define MSG_MEM_SCALE 32

-#define MSGMNI 16 /* <= IPCMNI */ /* max # of msg queue identifiers */
+#define MSGMNI 16 /* <= IPCMNI_MAX */ /* max # of msg queue identifiers */
#define MSGMAX 8192 /* <= INT_MAX */ /* max size of message (bytes) */
#define MSGMNB 16384 /* <= INT_MAX */ /* default max size of a message queue */

Index: linux-2.6/include/linux/sem.h
===================================================================
--- linux-2.6.orig/include/linux/sem.h
+++ linux-2.6/include/linux/sem.h
@@ -63,7 +63,7 @@ struct seminfo {
int semaem;
};

-#define SEMMNI 128 /* <= IPCMNI max # of semaphore identifiers */
+#define SEMMNI 128 /* <= IPCMNI_MAX max semaphore identifiers */
#define SEMMSL 250 /* <= 8 000 max num of semaphores per id */
#define SEMMNS (SEMMNI*SEMMSL) /* <= INT_MAX max # of semaphores in system */
#define SEMOPM 32 /* <= 1 000 max num of ops per semop call */
Index: linux-2.6/include/linux/shm.h
===================================================================
--- linux-2.6.orig/include/linux/shm.h
+++ linux-2.6/include/linux/shm.h
@@ -14,15 +14,15 @@
* be increased by sysctl
*/

-#define SHMMAX 0x2000000 /* max shared seg size (bytes) */
-#define SHMMIN 1 /* min shared seg size (bytes) */
-#define SHMMNI 4096 /* max num of segs system wide */
+#define SHMMAX 0x2000000 /* max shared seg size (bytes) */
+#define SHMMIN 1 /* min shared seg size (bytes) */
+#define SHMMNI 4096 /* <= IPCMNI_MAX max num of segs system wide */
#ifdef __KERNEL__
#define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
#else
#define SHMALL (SHMMAX/getpagesize()*(SHMMNI/16))
#endif
-#define SHMSEG SHMMNI /* max shared segs per process */
+#define SHMSEG SHMMNI /* max shared segs per process */

#ifdef __KERNEL__
#include <asm/shmparam.h>
Index: linux-2.6/ipc/msg.c
===================================================================
--- linux-2.6.orig/ipc/msg.c
+++ linux-2.6/ipc/msg.c
@@ -81,7 +81,7 @@ static int sysvipc_msg_proc_show(struct
* Scale msgmni with the available lowmem size: the memory dedicated to msg
* queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
* Also take into account the number of nsproxies created so far.
- * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
+ * This should be done staying within the (MSGMNI , IPCMNI_MAX/nr_ipc_ns) range.
*/
void recompute_msgmni(struct ipc_namespace *ns)
{
@@ -100,8 +100,8 @@ void recompute_msgmni(struct ipc_namespa
return;
}

- if (allowed > IPCMNI / nb_ns) {
- ns->msg_ctlmni = IPCMNI / nb_ns;
+ if (allowed > IPCMNI_MAX / nb_ns) {
+ ns->msg_ctlmni = IPCMNI_MAX / nb_ns;
return;
}

Index: linux-2.6/ipc/util.c
===================================================================
--- linux-2.6.orig/ipc/util.c
+++ linux-2.6/ipc/util.c
@@ -113,7 +113,7 @@ __initcall(ipc_init);
* @ids: Identifier set
*
* Set up the sequence range to use for the ipc identifier range (limited
- * below IPCMNI) then initialise the ids idr.
+ * below IPCMNI_MAX) then initialise the ids idr.
*/

void ipc_init_ids(struct ipc_ids *ids)
@@ -218,12 +218,12 @@ int ipc_get_maxid(struct ipc_ids *ids)
if (ids->in_use == 0)
return -1;

- if (ids->in_use == IPCMNI)
- return IPCMNI - 1;
+ if (ids->in_use == IPCMNI_MAX)
+ return IPCMNI_MAX - 1;

/* Look for the last assigned id */
total = 0;
- for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
+ for (id = 0; id < IPCMNI_MAX && total < ids->in_use; id++) {
ipc = idr_find(&ids->ipcs_idr, id);
if (ipc != NULL) {
max_id = id;
@@ -253,8 +253,8 @@ int ipc_addid(struct ipc_ids* ids, struc
gid_t egid;
int id, err;

- if (size > IPCMNI)
- size = IPCMNI;
+ if (size > IPCMNI_MAX)
+ size = IPCMNI_MAX;

if (ids->in_use >= size)
return -ENOSPC;
@@ -859,7 +859,7 @@ static struct kern_ipc_perm *sysvipc_fin
if (total >= ids->in_use)
return NULL;

- for ( ; pos < IPCMNI; pos++) {
+ for ( ; pos < IPCMNI_MAX; pos++) {
ipc = idr_find(&ids->ipcs_idr, pos);
if (ipc != NULL) {
*new_pos = pos + 1;
Index: linux-2.6/ipc/util.h
===================================================================
--- linux-2.6.orig/ipc/util.h
+++ linux-2.6/ipc/util.h
@@ -13,7 +13,9 @@
#include <linux/unistd.h>
#include <linux/err.h>

-#define SEQ_MULTIPLIER (IPCMNI)
+#define IPCMNI_MAX 32768 /* <= MAX_INT absolute limit for ipc arrays */
+
+#define SEQ_MULTIPLIER (IPCMNI_MAX)

void sem_init (void);
void msg_init (void);

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