@@ -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
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. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/sysfs/file.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-)