4 files changed, 33 insertions, 3 deletions

diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt
index 88fd7f5c8dcd..13d6166d7a27 100644
--- a/Documentation/sysctl/fs.txt
+++ b/Documentation/sysctl/fs.txt
@@ -225,6 +225,13 @@ a queue must be less or equal then msg_max.
 maximum  message size value (it is every  message queue's attribute set during
 its creation).
 
+/proc/sys/fs/mqueue/msg_default is  a read/write  file for setting/getting the
+default number of messages in a queue value if attr parameter of mq_open(2) is
+NULL. If it exceed msg_max, the default value is initialized msg_max.
+
+/proc/sys/fs/mqueue/msgsize_default is a read/write file for setting/getting
+the default message size value if attr parameter of mq_open(2) is NULL. If it
+exceed msgsize_max, the default value is initialized msgsize_max.
 
 4. /proc/sys/fs/epoll - Configuration options for the epoll interface
 --------------------------------------------------------
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 2488535a32a3..5499c92a9153 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -62,6 +62,8 @@ struct ipc_namespace {
         unsigned int    mq_queues_max;   /* initialized to DFLT_QUEUESMAX */
         unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
         unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
+        unsigned int    mq_msg_default;
+        unsigned int    mq_msgsize_default;
 
         /* user_ns which owns the ipc ns */
         struct user_namespace *user_ns;
diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c
index e22336a09b4a..383d638340b8 100644
--- a/ipc/mq_sysctl.c
+++ b/ipc/mq_sysctl.c
@@ -73,6 +73,24 @@ static ctl_table mq_sysctls[] = {
                 .extra1         = &msg_maxsize_limit_min,
                 .extra2         = &msg_maxsize_limit_max,
         },
+        {
+                .procname       = "msg_default",
+                .data           = &init_ipc_ns.mq_msg_default,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_mq_dointvec_minmax,
+                .extra1         = &msg_max_limit_min,
+                .extra2         = &msg_max_limit_max,
+        },
+        {
+                .procname       = "msgsize_default",
+                .data           = &init_ipc_ns.mq_msgsize_default,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_mq_dointvec_minmax,
+                .extra1         = &msg_maxsize_limit_min,
+                .extra2         = &msg_maxsize_limit_max,
+        },
         {}
 };
 
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 6828e2c93cef..609d53f7a915 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -145,9 +145,10 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
                 info->qsize = 0;
                 info->user = NULL;      /* set when all is ok */
                 memset(&info->attr, 0, sizeof(info->attr));
-                info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, DFLT_MSG);
-                info->attr.mq_msgsize =
-                        min(ipc_ns->mq_msgsize_max, DFLT_MSGSIZE);
+                info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
+                                           ipc_ns->mq_msg_default);
+                info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
+                                            ipc_ns->mq_msgsize_default);
                 if (attr) {
                         info->attr.mq_maxmsg = attr->mq_maxmsg;
                         info->attr.mq_msgsize = attr->mq_msgsize;
@@ -1261,6 +1262,8 @@ int mq_init_ns(struct ipc_namespace *ns)
         ns->mq_queues_max    = DFLT_QUEUESMAX;
         ns->mq_msg_max       = DFLT_MSGMAX;
         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
+        ns->mq_msg_default   = DFLT_MSG;
+        ns->mq_msgsize_default  = DFLT_MSGSIZE;
 
         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
         if (IS_ERR(ns->mq_mnt)) {