sysfs: simplify sysfs_kf_seq_show

Contrary to the comment ->show is never called from lseek for sysfs,
given that sysfs does not use seq_lseek.  So remove the NULL ->show
case and just WARN and return an error if some future code path ends
up here.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210913054121.616001-7-hch@lst.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christoph Hellwig 2021-09-13 07:41:14 +02:00 committed by Greg Kroah-Hartman
parent d1a1a9606e
commit 820879ee18

View File

@ -45,6 +45,9 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
ssize_t count;
char *buf;
if (WARN_ON_ONCE(!ops->show))
return -EINVAL;
/* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
count = seq_get_buf(sf, &buf);
if (count < PAGE_SIZE) {
@ -53,15 +56,9 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
}
memset(buf, 0, PAGE_SIZE);
/*
* Invoke show(). Control may reach here via seq file lseek even
* if @ops->show() isn't implemented.
*/
if (ops->show) {
count = ops->show(kobj, of->kn->priv, buf);
if (count < 0)
return count;
}
count = ops->show(kobj, of->kn->priv, buf);
if (count < 0)
return count;
/*
* The code works fine with PAGE_SIZE return but it's likely to