Re: [PATCH v2 0/3] sysfs: constify bin_attribute argument of sysfs_bin_attr_simple_read()

[Greg Kroah-Hartman]

On Thu, Jan 09, 2025 at 12:06:09AM -0800, Christoph Hellwig wrote:
> On Thu, Jan 09, 2025 at 08:56:37AM +0100, Greg Kroah-Hartman wrote:
> > The "pointless" penalty will go away once we convert all instances, and
> > really, it's just one pointer check, sysfs files should NOT be a hot
> > path for anything real, and one more pointer check should be cached and
> > not measurable compared to the real logic behind the binary data coming
> > from the hardware/kernel, right?
> > 
> > sysfs is NOT tuned for speed at all, so adding more checks like this
> > should be fine.
> 
> Hey, when I duplicated the method to convert sysfs over to a proper
> seq_file based approach that avoids buffer overflows you basically
> came up with the same line that Alexei had here.

I did?  Sorry about that, I don't remember that.

> And that is a lot
> more useful than constification. Not that I mind the latter, but it
> would be better if it could be done without leaving both variants
> in for long.

I agree, we should get the read_new stuff out in the next kernel cycle I
hope.

As for seq_file for sysfs, is that for binary attributes only, or for
all?  I can't recall that at all.

thanks,

greg k-h