staging: comedi: vmk80xx: cleanup digital input subdevice init

[pandora-kernel.git] / ipc / msg.c

diff --git a/ipc/msg.c b/ipc/msg.c
index 2f272fa..950572f 100644 (file)
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -755,26 +755,91 @@ static inline int convert_mode(long *msgtyp, int msgflg)
        return SEARCH_EQUAL;
 }
 
-long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
-               size_t msgsz, long msgtyp, int msgflg)
+static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
+{
+       struct msgbuf __user *msgp = dest;
+       size_t msgsz;
+
+       if (put_user(msg->m_type, &msgp->mtype))
+               return -EFAULT;
+
+       msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
+       if (store_msg(msgp->mtext, msg, msgsz))
+               return -EFAULT;
+       return msgsz;
+}
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+/*
+ * This function creates new kernel message structure, large enough to store
+ * bufsz message bytes.
+ */
+static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz,
+                                          int msgflg, long *msgtyp,
+                                          unsigned long *copy_number)
+{
+       struct msg_msg *copy;
+
+       *copy_number = *msgtyp;
+       *msgtyp = 0;
+       /*
+        * Create dummy message to copy real message to.
+        */
+       copy = load_msg(buf, bufsz);
+       if (!IS_ERR(copy))
+               copy->m_ts = bufsz;
+       return copy;
+}
+
+static inline void free_copy(struct msg_msg *copy)
+{
+       if (copy)
+               free_msg(copy);
+}
+#else
+static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz,
+                                          int msgflg, long *msgtyp,
+                                          unsigned long *copy_number)
+{
+       return ERR_PTR(-ENOSYS);
+}
+
+static inline void free_copy(struct msg_msg *copy)
+{
+}
+#endif
+
+long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
+              int msgflg,
+              long (*msg_handler)(void __user *, struct msg_msg *, size_t))
 {
        struct msg_queue *msq;
        struct msg_msg *msg;
        int mode;
        struct ipc_namespace *ns;
+       struct msg_msg *copy = NULL;
+       unsigned long copy_number = 0;
 
-       if (msqid < 0 || (long) msgsz < 0)
+       if (msqid < 0 || (long) bufsz < 0)
                return -EINVAL;
+       if (msgflg & MSG_COPY) {
+               copy = prepare_copy(buf, bufsz, msgflg, &msgtyp, &copy_number);
+               if (IS_ERR(copy))
+                       return PTR_ERR(copy);
+       }
        mode = convert_mode(&msgtyp, msgflg);
        ns = current->nsproxy->ipc_ns;
 
        msq = msg_lock_check(ns, msqid);
-       if (IS_ERR(msq))
+       if (IS_ERR(msq)) {
+               free_copy(copy);
                return PTR_ERR(msq);
+       }
 
        for (;;) {
                struct msg_receiver msr_d;
                struct list_head *tmp;
+               long msg_counter = 0;
 
                msg = ERR_PTR(-EACCES);
                if (ipcperms(ns, &msq->q_perm, S_IRUGO))
@@ -794,8 +859,20 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
                                if (mode == SEARCH_LESSEQUAL &&
                                                walk_msg->m_type != 1) {
                                        msgtyp = walk_msg->m_type - 1;
+                               } else if (msgflg & MSG_COPY) {
+                                       if (copy_number == msg_counter) {
+                                               /*
+                                                * Found requested message.
+                                                * Copy it.
+                                                */
+                                               msg = copy_msg(msg, copy);
+                                               if (IS_ERR(msg))
+                                                       goto out_unlock;
+                                               break;
+                                       }
                                } else
                                        break;
+                               msg_counter++;
                        }
                        tmp = tmp->next;
                }
@@ -804,10 +881,16 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
                         * Found a suitable message.
                         * Unlink it from the queue.
                         */
-                       if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
+                       if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
                                msg = ERR_PTR(-E2BIG);
                                goto out_unlock;
                        }
+                       /*
+                        * If we are copying, then do not unlink message and do
+                        * not update queue parameters.
+                        */
+                       if (msgflg & MSG_COPY)
+                               goto out_unlock;
                        list_del(&msg->m_list);
                        msq->q_qnum--;
                        msq->q_rtime = get_seconds();
@@ -831,7 +914,7 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
                if (msgflg & MSG_NOERROR)
                        msr_d.r_maxsize = INT_MAX;
                else
-                       msr_d.r_maxsize = msgsz;
+                       msr_d.r_maxsize = bufsz;
                msr_d.r_msg = ERR_PTR(-EAGAIN);
                current->state = TASK_INTERRUPTIBLE;
                msg_unlock(msq);
@@ -891,32 +974,21 @@ out_unlock:
                        break;
                }
        }
-       if (IS_ERR(msg))
+       if (IS_ERR(msg)) {
+               free_copy(copy);
                return PTR_ERR(msg);
+       }
 
-       msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
-       *pmtype = msg->m_type;
-       if (store_msg(mtext, msg, msgsz))
-               msgsz = -EFAULT;
-
+       bufsz = msg_handler(buf, msg, bufsz);
        free_msg(msg);
 
-       return msgsz;
+       return bufsz;
 }
 
 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
                long, msgtyp, int, msgflg)
 {
-       long err, mtype;
-
-       err =  do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
-       if (err < 0)
-               goto out;
-
-       if (put_user(mtype, &msgp->mtype))
-               err = -EFAULT;
-out:
-       return err;
+       return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
 }
 
 #ifdef CONFIG_PROC_FS