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[PATCH] generic_file_llseek tidyups

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2008-08-11 15:37:17 +02:00 committed by Al Viro
parent a518ab9329
commit 3a8cff4f02
1 changed files with 40 additions and 18 deletions
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58
fs/read_write.c
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@ -31,39 +31,61 @@ 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) {
case SEEK_END:
offset += inode->i_size;
break;
case SEEK_CUR:
offset += file->f_pos;
case SEEK_END:
offset += inode->i_size;
break;
case SEEK_CUR:
offset += file->f_pos;
break;
}
retval = -EINVAL;
if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
/* Special lock needed here? */
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
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;
}
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);