Mauro, Hans,
The debugfs code in drivers/media/common/siano/smsdvb-debugfs.c is
completely broken. No one has tested it since Dec 2022. Can we just
remove it?
On Mon, May 27, 2024 at 11:14:16AM +0300, Dan Carpenter wrote:
> On Sat, May 25, 2024 at 05:00:59PM +0300, Andy Shevchenko wrote:
> > On Thu, May 23, 2024 at 3:42 PM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> >
> >
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1110 static ssize_t hx9031as_raw_data_show(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1111 {
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1112 char buf[BUF_SIZE] = {0};
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1113 char *p = buf;
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1114 int ii = 0;
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1115
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1116 hx9031as_sample();
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 1117 for (ii = 0; ii < HX9031AS_CH_NUM; ii++) {
> > > 5e5a419c9407f6 Yasin Lee 2024-05-10 @1118 p += snprintf(p, PAGE_SIZE, "ch[%d]: DIFF=%-8d, RAW=%-8d, OFFSET=%-8d, BL=%-8d, LP=%-8d\n",
> > > ^^^^^^^^^
> >
> >
> > > Also use scnprintf() instead of snprintf() unless you need to check the
> > > results.
> >
> > This is incorrect advice. You should recommend sysfs_emit() /
> > sysfs_emit_at() in this kind of case.
>
> No, this is not sysfs code. It's debugfs. The API is completely
> different.
I was going to say that if you find yourself calling sysfs_emit_at()
then you're already in trouble because sysfs is supposed to be one thing
per file.
But then I searched and we call it almost 1000 times.
The first caller I looked at was drivers/media/common/siano/smsdvb-debugfs.c
from commit 2f7d0c94396e ("media: siano: Convert to use sysfs_emit_at()
API") which changes debugfs code to use sysfs_emit(). And it so clearly
has never been tested because debug_data->stats_data does not point to
the start of a page. sysfs_emit() will refuse to print anything unless
it's given a pointer to the start of a page. Ugh...
regards,
dan carpenter
