introduce variants of pipe_lock/pipe_unlock for real pipes/FIFOs

fs/pipe.c file_operations methods *know* that pipe is not an internal one;
no need to check pipe->inode for those callers.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/pipe.c b/fs/pipe.c
index 161b2099a7af864f378a941d534daa8e74031ae9..e2fc5ccb0d49b65bb50ed29dd2bbfedd06947d43 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -75,6 +75,16 @@ void pipe_unlock(struct pipe_inode_info *pipe)
 }
 EXPORT_SYMBOL(pipe_unlock);
 
+static inline void __pipe_lock(struct pipe_inode_info *pipe)
+{
+       mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT);
+}
+
+static inline void __pipe_unlock(struct pipe_inode_info *pipe)
+{
+       mutex_unlock(&pipe->mutex);
+}
+
 void pipe_double_lock(struct pipe_inode_info *pipe1,
                      struct pipe_inode_info *pipe2)
 {
@@ -376,7 +386,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
 
        do_wakeup = 0;
        ret = 0;
-       pipe_lock(pipe);
+       __pipe_lock(pipe);
        for (;;) {
                int bufs = pipe->nrbufs;
                if (bufs) {
@@ -464,7 +474,7 @@ redo:
                }
                pipe_wait(pipe);
        }
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
 
        /* Signal writers asynchronously that there is more room. */
        if (do_wakeup) {
@@ -500,7 +510,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
 
        do_wakeup = 0;
        ret = 0;
-       pipe_lock(pipe);
+       __pipe_lock(pipe);
 
        if (!pipe->readers) {
                send_sig(SIGPIPE, current, 0);
@@ -647,7 +657,7 @@ redo2:
                pipe->waiting_writers--;
        }
 out:
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
        if (do_wakeup) {
                wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
                kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
@@ -667,7 +677,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
        switch (cmd) {
                case FIONREAD:
-                       pipe_lock(pipe);
+                       __pipe_lock(pipe);
                        count = 0;
                        buf = pipe->curbuf;
                        nrbufs = pipe->nrbufs;
@@ -675,7 +685,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                                count += pipe->bufs[buf].len;
                                buf = (buf+1) & (pipe->buffers - 1);
                        }
-                       pipe_unlock(pipe);
+                       __pipe_unlock(pipe);
 
                        return put_user(count, (int __user *)arg);
                default:
@@ -721,7 +731,7 @@ pipe_release(struct inode *inode, struct file *file)
        struct pipe_inode_info *pipe = inode->i_pipe;
        int kill = 0;
 
-       pipe_lock(pipe);
+       __pipe_lock(pipe);
        if (file->f_mode & FMODE_READ)
                pipe->readers--;
        if (file->f_mode & FMODE_WRITE)
@@ -738,7 +748,7 @@ pipe_release(struct inode *inode, struct file *file)
                kill = 1;
        }
        spin_unlock(&inode->i_lock);
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
 
        if (kill)
                __free_pipe_info(pipe);
@@ -752,7 +762,7 @@ pipe_fasync(int fd, struct file *filp, int on)
        struct pipe_inode_info *pipe = filp->private_data;
        int retval = 0;
 
-       pipe_lock(pipe);
+       __pipe_lock(pipe);
        if (filp->f_mode & FMODE_READ)
                retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
        if ((filp->f_mode & FMODE_WRITE) && retval >= 0) {
@@ -761,7 +771,7 @@ pipe_fasync(int fd, struct file *filp, int on)
                        /* this can happen only if on == T */
                        fasync_helper(-1, filp, 0, &pipe->fasync_readers);
        }
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
        return retval;
 }
 
@@ -1040,7 +1050,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
        filp->private_data = pipe;
        /* OK, we have a pipe and it's pinned down */
 
-       pipe_lock(pipe);
+       __pipe_lock(pipe);
 
        /* We can only do regular read/write on fifos */
        filp->f_mode &= (FMODE_READ | FMODE_WRITE);
@@ -1110,7 +1120,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
        }
 
        /* Ok! */
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
        return 0;
 
 err_rd:
@@ -1132,7 +1142,7 @@ err:
                kill = 1;
        }
        spin_unlock(&inode->i_lock);
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
        if (kill)
                __free_pipe_info(pipe);
        return ret;
@@ -1248,7 +1258,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
        if (!pipe)
                return -EBADF;
 
-       pipe_lock(pipe);
+       __pipe_lock(pipe);
 
        switch (cmd) {
        case F_SETPIPE_SZ: {
@@ -1277,7 +1287,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
        }
 
 out:
-       pipe_unlock(pipe);
+       __pipe_unlock(pipe);
        return ret;
 }