fold fifo.c into pipe.c

[karo-tx-linux.git] / fs / pipe.c

diff --git a/fs/pipe.c b/fs/pipe.c
index 2234f3f61f8d8fbc6a1f77dbaae6412130b8a5d4..aed80c25cd408079b2afefcd1bc18ea9f5c75fc6 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1144,6 +1144,144 @@ SYSCALL_DEFINE1(pipe, int __user *, fildes)
        return sys_pipe2(fildes, 0);
 }
 
+static int wait_for_partner(struct inode* inode, unsigned int *cnt)
+{
+       int cur = *cnt; 
+
+       while (cur == *cnt) {
+               pipe_wait(inode->i_pipe);
+               if (signal_pending(current))
+                       break;
+       }
+       return cur == *cnt ? -ERESTARTSYS : 0;
+}
+
+static void wake_up_partner(struct inode* inode)
+{
+       wake_up_interruptible(&inode->i_pipe->wait);
+}
+
+static int fifo_open(struct inode *inode, struct file *filp)
+{
+       struct pipe_inode_info *pipe;
+       int ret;
+
+       mutex_lock(&inode->i_mutex);
+       pipe = inode->i_pipe;
+       if (!pipe) {
+               ret = -ENOMEM;
+               pipe = alloc_pipe_info(inode);
+               if (!pipe)
+                       goto err_nocleanup;
+               inode->i_pipe = pipe;
+       }
+       filp->f_version = 0;
+
+       /* We can only do regular read/write on fifos */
+       filp->f_mode &= (FMODE_READ | FMODE_WRITE);
+
+       switch (filp->f_mode) {
+       case FMODE_READ:
+       /*
+        *  O_RDONLY
+        *  POSIX.1 says that O_NONBLOCK means return with the FIFO
+        *  opened, even when there is no process writing the FIFO.
+        */
+               filp->f_op = &read_pipefifo_fops;
+               pipe->r_counter++;
+               if (pipe->readers++ == 0)
+                       wake_up_partner(inode);
+
+               if (!pipe->writers) {
+                       if ((filp->f_flags & O_NONBLOCK)) {
+                               /* suppress POLLHUP until we have
+                                * seen a writer */
+                               filp->f_version = pipe->w_counter;
+                       } else {
+                               if (wait_for_partner(inode, &pipe->w_counter))
+                                       goto err_rd;
+                       }
+               }
+               break;
+       
+       case FMODE_WRITE:
+       /*
+        *  O_WRONLY
+        *  POSIX.1 says that O_NONBLOCK means return -1 with
+        *  errno=ENXIO when there is no process reading the FIFO.
+        */
+               ret = -ENXIO;
+               if ((filp->f_flags & O_NONBLOCK) && !pipe->readers)
+                       goto err;
+
+               filp->f_op = &write_pipefifo_fops;
+               pipe->w_counter++;
+               if (!pipe->writers++)
+                       wake_up_partner(inode);
+
+               if (!pipe->readers) {
+                       if (wait_for_partner(inode, &pipe->r_counter))
+                               goto err_wr;
+               }
+               break;
+       
+       case FMODE_READ | FMODE_WRITE:
+       /*
+        *  O_RDWR
+        *  POSIX.1 leaves this case "undefined" when O_NONBLOCK is set.
+        *  This implementation will NEVER block on a O_RDWR open, since
+        *  the process can at least talk to itself.
+        */
+               filp->f_op = &rdwr_pipefifo_fops;
+
+               pipe->readers++;
+               pipe->writers++;
+               pipe->r_counter++;
+               pipe->w_counter++;
+               if (pipe->readers == 1 || pipe->writers == 1)
+                       wake_up_partner(inode);
+               break;
+
+       default:
+               ret = -EINVAL;
+               goto err;
+       }
+
+       /* Ok! */
+       mutex_unlock(&inode->i_mutex);
+       return 0;
+
+err_rd:
+       if (!--pipe->readers)
+               wake_up_interruptible(&pipe->wait);
+       ret = -ERESTARTSYS;
+       goto err;
+
+err_wr:
+       if (!--pipe->writers)
+               wake_up_interruptible(&pipe->wait);
+       ret = -ERESTARTSYS;
+       goto err;
+
+err:
+       if (!pipe->readers && !pipe->writers)
+               free_pipe_info(inode);
+
+err_nocleanup:
+       mutex_unlock(&inode->i_mutex);
+       return ret;
+}
+
+/*
+ * Dummy default file-operations: the only thing this does
+ * is contain the open that then fills in the correct operations
+ * depending on the access mode of the file...
+ */
+const struct file_operations def_fifo_fops = {
+       .open           = fifo_open,    /* will set read_ or write_pipefifo_fops */
+       .llseek         = noop_llseek,
+};
+
 /*
  * Allocate a new array of pipe buffers and copy the info over. Returns the
  * pipe size if successful, or return -ERROR on error.