Commit 3a8cff4f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

[PATCH] generic_file_llseek tidyups 



Add kerneldoc for generic_file_llseek and generic_file_llseek_unlocked,
use sane variable names and unclutter the code.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a518ab93

fs/read_write.c

+40 −18
Original line number Diff line number Diff line
@@ -31,10 +31,18 @@ const struct file_operations generic_ro_fops = { 


EXPORT_SYMBOL(generic_ro_fops);



/**

 * generic_file_llseek_unlocked - lockless generic llseek implementation

 * @file:	file structure to seek on

 * @offset:	file offset to seek to

 * @origin:	type of seek

 *

 * Updates the file offset to the value specified by @offset and @origin.

 * Locking must be provided by the caller.

 */

loff_t

generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)

{

	loff_t retval;

	struct inode *inode = file->f_mapping->host;



	switch (origin) {
@@ -43,27 +51,41 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin) 
		break;

	case SEEK_CUR:

		offset += file->f_pos;

		break;

	}

	retval = -EINVAL;

	if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {



	if (offset < 0 || offset > inode->i_sb->s_maxbytes)

		return -EINVAL;



	/* Special lock needed here? */

	if (offset != file->f_pos) {

		file->f_pos = offset;

		file->f_version = 0;

	}

		retval = offset;

	}

	return retval;



	return offset;

}

EXPORT_SYMBOL(generic_file_llseek_unlocked);



/**

 * generic_file_llseek - generic llseek implementation for regular files

 * @file:	file structure to seek on

 * @offset:	file offset to seek to

 * @origin:	type of seek

 *

 * This is a generic implemenation of ->llseek useable for all normal local

 * filesystems.  It just updates the file offset to the value specified by

 * @offset and @origin under i_mutex.

 */

loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)

{

	loff_t n;

	loff_t rval;



	mutex_lock(&file->f_dentry->d_inode->i_mutex);

	n = generic_file_llseek_unlocked(file, offset, origin);

	rval = generic_file_llseek_unlocked(file, offset, origin);

	mutex_unlock(&file->f_dentry->d_inode->i_mutex);

	return n;



	return rval;

}

EXPORT_SYMBOL(generic_file_llseek);