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Commit 18c03cfd authored by Al Viro's avatar Al Viro
Browse files

pipe: preparation to new locking rules 



* use the fact that file_inode(file)->i_pipe doesn't change
  while the file is opened - no locks needed to access that.
* switch to pipe_lock/pipe_unlock where it's easy to do

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent fc7478a2

fs/pipe.c

+15 −23
Original line number Diff line number Diff line
@@ -363,8 +363,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov, 
	   unsigned long nr_segs, loff_t pos)

{

	struct file *filp = iocb->ki_filp;

	struct inode *inode = file_inode(filp);

	struct pipe_inode_info *pipe;

	struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;

	int do_wakeup;

	ssize_t ret;

	struct iovec *iov = (struct iovec *)_iov;
@@ -377,8 +376,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov, 


	do_wakeup = 0;

	ret = 0;

	mutex_lock(&inode->i_mutex);

	pipe = inode->i_pipe;

	pipe_lock(pipe);

	for (;;) {

		int bufs = pipe->nrbufs;

		if (bufs) {
@@ -466,7 +464,7 @@ redo: 
		}

		pipe_wait(pipe);

	}

	mutex_unlock(&inode->i_mutex);

	pipe_unlock(pipe);



	/* Signal writers asynchronously that there is more room. */

	if (do_wakeup) {
@@ -488,8 +486,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov, 
	    unsigned long nr_segs, loff_t ppos)

{

	struct file *filp = iocb->ki_filp;

	struct inode *inode = file_inode(filp);

	struct pipe_inode_info *pipe;

	struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;

	ssize_t ret;

	int do_wakeup;

	struct iovec *iov = (struct iovec *)_iov;
@@ -503,8 +500,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov, 


	do_wakeup = 0;

	ret = 0;

	mutex_lock(&inode->i_mutex);

	pipe = inode->i_pipe;

	pipe_lock(pipe);



	if (!pipe->readers) {

		send_sig(SIGPIPE, current, 0);
@@ -651,7 +647,7 @@ redo2: 
		pipe->waiting_writers--;

	}

out:

	mutex_unlock(&inode->i_mutex);

	pipe_unlock(pipe);

	if (do_wakeup) {

		wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);

		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
@@ -666,14 +662,12 @@ out: 


static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)

{

	struct inode *inode = file_inode(filp);

	struct pipe_inode_info *pipe;

	struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;

	int count, buf, nrbufs;



	switch (cmd) {

		case FIONREAD:

			mutex_lock(&inode->i_mutex);

			pipe = inode->i_pipe;

			pipe_lock(pipe);

			count = 0;

			buf = pipe->curbuf;

			nrbufs = pipe->nrbufs;
@@ -681,7 +675,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
				count += pipe->bufs[buf].len;

				buf = (buf+1) & (pipe->buffers - 1);

			}

			mutex_unlock(&inode->i_mutex);

			pipe_unlock(pipe);



			return put_user(count, (int __user *)arg);

		default:
@@ -694,8 +688,7 @@ static unsigned int 
pipe_poll(struct file *filp, poll_table *wait)

{

	unsigned int mask;

	struct inode *inode = file_inode(filp);

	struct pipe_inode_info *pipe = inode->i_pipe;

	struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;

	int nrbufs;



	poll_wait(filp, &pipe->wait, wait);
@@ -749,11 +742,10 @@ pipe_release(struct inode *inode, struct file *file) 
static int

pipe_fasync(int fd, struct file *filp, int on)

{

	struct inode *inode = file_inode(filp);

	struct pipe_inode_info *pipe = inode->i_pipe;

	struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;

	int retval = 0;



	mutex_lock(&inode->i_mutex);

	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) {
@@ -762,7 +754,7 @@ pipe_fasync(int fd, struct file *filp, int on) 
			/* this can happen only if on == T */

			fasync_helper(-1, filp, 0, &pipe->fasync_readers);

	}

	mutex_unlock(&inode->i_mutex);

	pipe_unlock(pipe);

	return retval;

}
@@ -1224,7 +1216,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) 
	if (!pipe)

		return -EBADF;



	mutex_lock(&pipe->inode->i_mutex);

	pipe_lock(pipe);



	switch (cmd) {

	case F_SETPIPE_SZ: {
@@ -1253,7 +1245,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) 
	}



out:

	mutex_unlock(&pipe->inode->i_mutex);

	pipe_unlock(pipe);

	return ret;

}