The patch titled
Subject: ipc: add sysctl to specify desired next object id
has been removed from the -mm tree. Its filename was
ipc-add-sysctl-to-specify-desired-next-object-id.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
Subject: ipc: add sysctl to specify desired next object id
Add 3 new variables and sysctls to tune them (by one "next_id" variable
for messages, semaphores and shared memory respectively). This variable
can be used to set desired id for next allocated IPC object. By default
it's equal to -1 and old behaviour is preserved. If this variable is
non-negative, then desired idr will be extracted from it and used as a
start value to search for free IDR slot.
Notes:
1) this patch doesn't guarantee that the new object will have desired
id. So it's up to user space how to handle new object with wrong id.
2) After a sucessful id allocation attempt, "next_id" will be set back
to -1 (if it was non-negative).
[akpm@xxxxxxxxxxxxxxxxxxxx: checkpatch fixes]
Signed-off-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/sysctl/kernel.txt | 19 +++++++++++++++++
include/linux/ipc_namespace.h | 1
ipc/ipc_sysctl.c | 32 ++++++++++++++++++++++++++++++
ipc/util.c | 16 +++++++++++----
ipc/util.h | 1
5 files changed, 65 insertions(+), 4 deletions(-)
diff -puN Documentation/sysctl/kernel.txt~ipc-add-sysctl-to-specify-desired-next-object-id Documentation/sysctl/kernel.txt
--- a/Documentation/sysctl/kernel.txt~ipc-add-sysctl-to-specify-desired-next-object-id
+++ a/Documentation/sysctl/kernel.txt
@@ -38,6 +38,7 @@ show up in /proc/sys/kernel:
- l2cr [ PPC only ]
- modprobe ==> Documentation/debugging-modules.txt
- modules_disabled
+- msg_next_id [ sysv ipc ]
- msgmax
- msgmnb
- msgmni
@@ -62,7 +63,9 @@ show up in /proc/sys/kernel:
- rtsig-max
- rtsig-nr
- sem
+- sem_next_id [ sysv ipc ]
- sg-big-buff [ generic SCSI device (sg) ]
+- shm_next_id [ sysv ipc ]
- shm_rmid_forced
- shmall
- shmmax [ sysv ipc ]
@@ -320,6 +323,22 @@ to false.
==============================================================
+msg_next_id, sem_next_id, and shm_next_id:
+
+These three toggles allows to specify desired id for next allocated IPC
+object: message, semaphore or shared memory respectively.
+
+By default they are equal to -1, which means generic allocation logic.
+Possible values to set are in range {0..INT_MAX}.
+
+Notes:
+1) kernel doesn't guarantee, that new object will have desired id. So,
+it's up to userspace, how to handle an object with "wrong" id.
+2) Toggle with non-default value will be set back to -1 by kernel after
+successful IPC object allocation.
+
+==============================================================
+
nmi_watchdog:
Enables/Disables the NMI watchdog on x86 systems. When the value is
diff -puN include/linux/ipc_namespace.h~ipc-add-sysctl-to-specify-desired-next-object-id include/linux/ipc_namespace.h
--- a/include/linux/ipc_namespace.h~ipc-add-sysctl-to-specify-desired-next-object-id
+++ a/include/linux/ipc_namespace.h
@@ -24,6 +24,7 @@ struct ipc_ids {
unsigned short seq_max;
struct rw_semaphore rw_mutex;
struct idr ipcs_idr;
+ int next_id;
};
struct ipc_namespace {
diff -puN ipc/ipc_sysctl.c~ipc-add-sysctl-to-specify-desired-next-object-id ipc/ipc_sysctl.c
--- a/ipc/ipc_sysctl.c~ipc-add-sysctl-to-specify-desired-next-object-id
+++ a/ipc/ipc_sysctl.c
@@ -158,6 +158,9 @@ static int proc_ipcauto_dointvec_minmax(
static int zero;
static int one = 1;
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int int_max = INT_MAX;
+#endif
static struct ctl_table ipc_kern_table[] = {
{
@@ -227,6 +230,35 @@ static struct ctl_table ipc_kern_table[]
.extra1 = &zero,
.extra2 = &one,
},
+#ifdef CONFIG_CHECKPOINT_RESTORE
+ {
+ .procname = "sem_next_id",
+ .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
+ .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
+ .mode = 0644,
+ .proc_handler = proc_ipc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &int_max,
+ },
+ {
+ .procname = "msg_next_id",
+ .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
+ .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
+ .mode = 0644,
+ .proc_handler = proc_ipc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &int_max,
+ },
+ {
+ .procname = "shm_next_id",
+ .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
+ .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
+ .mode = 0644,
+ .proc_handler = proc_ipc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &int_max,
+ },
+#endif
{}
};
diff -puN ipc/util.c~ipc-add-sysctl-to-specify-desired-next-object-id ipc/util.c
--- a/ipc/util.c~ipc-add-sysctl-to-specify-desired-next-object-id
+++ a/ipc/util.c
@@ -122,6 +122,7 @@ void ipc_init_ids(struct ipc_ids *ids)
ids->in_use = 0;
ids->seq = 0;
+ ids->next_id = -1;
{
int seq_limit = INT_MAX/SEQ_MULTIPLIER;
if (seq_limit > USHRT_MAX)
@@ -252,6 +253,7 @@ int ipc_addid(struct ipc_ids* ids, struc
kuid_t euid;
kgid_t egid;
int id, err;
+ int next_id = ids->next_id;
if (size > IPCMNI)
size = IPCMNI;
@@ -264,7 +266,8 @@ int ipc_addid(struct ipc_ids* ids, struc
rcu_read_lock();
spin_lock(&new->lock);
- err = idr_get_new(&ids->ipcs_idr, new, &id);
+ err = idr_get_new_above(&ids->ipcs_idr, new,
+ (next_id < 0) ? 0 : ipcid_to_idx(next_id), &id);
if (err) {
spin_unlock(&new->lock);
rcu_read_unlock();
@@ -277,9 +280,14 @@ int ipc_addid(struct ipc_ids* ids, struc
new->cuid = new->uid = euid;
new->gid = new->cgid = egid;
- new->seq = ids->seq++;
- if(ids->seq > ids->seq_max)
- ids->seq = 0;
+ if (next_id < 0) {
+ new->seq = ids->seq++;
+ if (ids->seq > ids->seq_max)
+ ids->seq = 0;
+ } else {
+ new->seq = ipcid_to_seqx(next_id);
+ ids->next_id = -1;
+ }
new->id = ipc_buildid(id, new->seq);
return id;
diff -puN ipc/util.h~ipc-add-sysctl-to-specify-desired-next-object-id ipc/util.h
--- a/ipc/util.h~ipc-add-sysctl-to-specify-desired-next-object-id
+++ a/ipc/util.h
@@ -92,6 +92,7 @@ void __init ipc_init_proc_interface(cons
#define IPC_SHM_IDS 2
#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
+#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
/* must be called with ids->rw_mutex acquired for writing */
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
_
Patches currently in -mm which might be from skinsbursky@xxxxxxxxxxxxx are
origin.patch
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