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Commit 341b446b authored by Ingo Molnar's avatar Ingo Molnar Committed by Jens Axboe
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[PATCH] another round of fs/pipe.c cleanups 



make pipe.c a bit more readable and hackable.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent 73d62d83

fs/pipe.c

+48 −28
Original line number Diff line number Diff line
@@ -44,7 +44,8 @@ void pipe_wait(struct pipe_inode_info *pipe) 
	 * Pipes are system-local resources, so sleeping on them

	 * is considered a noninteractive wait:

	 */

	prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE);

	prepare_to_wait(&pipe->wait, &wait,

			TASK_INTERRUPTIBLE | TASK_NONINTERACTIVE);

	if (pipe->inode)

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

	schedule();
@@ -93,7 +94,8 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) 
	return 0;

}



static void anon_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf)

static void anon_pipe_buf_release(struct pipe_inode_info *pipe,

				  struct pipe_buffer *buf)

{

	struct page *page = buf->page;
@@ -102,25 +104,22 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buff 
	/*

	 * If nobody else uses this page, and we don't already have a

	 * temporary page, let's keep track of it as a one-deep

	 * allocation cache

	 * allocation cache. (Otherwise just release our reference to it)

	 */

	if (page_count(page) == 1 && !pipe->tmp_page) {

	if (page_count(page) == 1 && !pipe->tmp_page)

		pipe->tmp_page = page;

		return;

	}



	/*

	 * Otherwise just release our reference to it

	 */

	else

		page_cache_release(page);

}



static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe, struct pipe_buffer *buf)

static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe,

				struct pipe_buffer *buf)

{

	return kmap(buf->page);

}



static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe, struct pipe_buffer *buf)

static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe,

				struct pipe_buffer *buf)

{

	kunmap(buf->page);

}
@@ -182,7 +181,8 @@ pipe_readv(struct file *filp, const struct iovec *_iov, 
			error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);

			ops->unmap(pipe, buf);

			if (unlikely(error)) {

				if (!ret) ret = -EFAULT;

				if (!ret)

					ret = -EFAULT;

				break;

			}

			ret += chars;
@@ -218,7 +218,8 @@ pipe_readv(struct file *filp, const struct iovec *_iov, 
			}

		}

		if (signal_pending(current)) {

			if (!ret) ret = -ERESTARTSYS;

			if (!ret)

				ret = -ERESTARTSYS;

			break;

		}

		if (do_wakeup) {
@@ -228,6 +229,7 @@ pipe_readv(struct file *filp, const struct iovec *_iov, 
		pipe_wait(pipe);

	}

	mutex_unlock(&inode->i_mutex);



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

	if (do_wakeup) {

		wake_up_interruptible(&pipe->wait);
@@ -242,6 +244,7 @@ static ssize_t 
pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)

{

	struct iovec iov = { .iov_base = buf, .iov_len = count };



	return pipe_readv(filp, &iov, 1, ppos);

}
@@ -276,10 +279,12 @@ pipe_writev(struct file *filp, const struct iovec *_iov, 
	/* We try to merge small writes */

	chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */

	if (pipe->nrbufs && chars != 0) {

		int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & (PIPE_BUFFERS-1);

		int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &

							(PIPE_BUFFERS-1);

		struct pipe_buffer *buf = pipe->bufs + lastbuf;

		struct pipe_buf_operations *ops = buf->ops;

		int offset = buf->offset + buf->len;



		if (ops->can_merge && offset + chars <= PAGE_SIZE) {

			void *addr;

			int error;
@@ -306,9 +311,11 @@ pipe_writev(struct file *filp, const struct iovec *_iov, 


	for (;;) {

		int bufs;



		if (!pipe->readers) {

			send_sig(SIGPIPE, current, 0);

			if (!ret) ret = -EPIPE;

			if (!ret)

				ret = -EPIPE;

			break;

		}

		bufs = pipe->nrbufs;
@@ -339,7 +346,8 @@ pipe_writev(struct file *filp, const struct iovec *_iov, 
			error = pipe_iov_copy_from_user(kmap(page), iov, chars);

			kunmap(page);

			if (unlikely(error)) {

				if (!ret) ret = -EFAULT;

				if (!ret)

					ret = -EFAULT;

				break;

			}

			ret += chars;
@@ -359,11 +367,13 @@ pipe_writev(struct file *filp, const struct iovec *_iov, 
		if (bufs < PIPE_BUFFERS)

			continue;

		if (filp->f_flags & O_NONBLOCK) {

			if (!ret) ret = -EAGAIN;

			if (!ret)

				ret = -EAGAIN;

			break;

		}

		if (signal_pending(current)) {

			if (!ret) ret = -ERESTARTSYS;

			if (!ret)

				ret = -ERESTARTSYS;

			break;

		}

		if (do_wakeup) {
@@ -391,6 +401,7 @@ pipe_write(struct file *filp, const char __user *buf, 
	   size_t count, loff_t *ppos)

{

	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };



	return pipe_writev(filp, &iov, 1, ppos);

}
@@ -401,7 +412,8 @@ bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) 
}



static ssize_t

bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos)

bad_pipe_w(struct file *filp, const char __user *buf, size_t count,

	   loff_t *ppos)

{

	return -EBADF;

}
@@ -475,6 +487,7 @@ pipe_release(struct inode *inode, int decr, int decw) 
	pipe = inode->i_pipe;

	pipe->readers -= decr;

	pipe->writers -= decw;



	if (!pipe->readers && !pipe->writers) {

		free_pipe_info(inode);

	} else {
@@ -525,14 +538,15 @@ static int 
pipe_rdwr_fasync(int fd, struct file *filp, int on)

{

	struct inode *inode = filp->f_dentry->d_inode;

	struct pipe_inode_info *pipe = inode->i_pipe;

	int retval;



	mutex_lock(&inode->i_mutex);



	retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers);

	retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);



	if (retval >= 0)

		retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers);

		retval = fasync_helper(fd, filp, on, &pipe->fasync_writers);



	mutex_unlock(&inode->i_mutex);
@@ -720,6 +734,7 @@ static int pipefs_delete_dentry(struct dentry *dentry) 
{

	return 1;

}



static struct dentry_operations pipefs_dentry_operations = {

	.d_delete	= pipefs_delete_dentry,

};
@@ -757,6 +772,7 @@ static struct inode * get_pipe_inode(void) 


fail_iput:

	iput(inode);



fail_inode:

	return NULL;

}
@@ -802,6 +818,7 @@ int do_pipe(int *fd) 
	dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);

	if (!dentry)

		goto close_f12_inode_i_j;



	dentry->d_op = &pipefs_dentry_operations;

	d_add(dentry, inode);

	f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt));
@@ -825,6 +842,7 @@ int do_pipe(int *fd) 
	fd_install(j, f2);

	fd[0] = i;

	fd[1] = j;



	return 0;



close_f12_inode_i_j:
@@ -849,8 +867,9 @@ no_files: 
 * d_name - pipe: will go nicely and kill the special-casing in procfs.

 */



static struct super_block *pipefs_get_sb(struct file_system_type *fs_type,

	int flags, const char *dev_name, void *data)

static struct super_block *

pipefs_get_sb(struct file_system_type *fs_type, int flags,

	      const char *dev_name, void *data)

{

	return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC);

}
@@ -864,6 +883,7 @@ static struct file_system_type pipe_fs_type = { 
static int __init init_pipe_fs(void)

{

	int err = register_filesystem(&pipe_fs_type);



	if (!err) {

		pipe_mnt = kern_mount(&pipe_fs_type);

		if (IS_ERR(pipe_mnt)) {