Re: [PATCH v4 1/2] docs: Add block device (blkdev) LED trigger documentation

[Christoph Hellwig]

On Sat, Sep 18, 2021 at 09:07:54AM +0200, Greg KH wrote:
> > Honestly, I wasn't particularly enthusiastic about it in the first
> > place; it feels like something that should be done in user space.  I
> > wouldn't have included it if I didn't have to make a writable copy of
> > the buffer anyway, in order to trim a trailing newline.
> > 
> > I can certainly remove the re-check logic.  The end result will be an
> > API that is slightly less "user friendly" in return for saving a bit of
> > pointer arithmetic and a 5-byte memcpy().
> 
> Just use the kernel block device name and that way you do not have to
> parse anything as it is unique and no paths are having to be followed.
> 
> That's the way that other LED apis are working, right?

The "kernel block device name" is the a block device special path
that a normal VFS path lookup is done on.  This is the preferred block
device API used by everyone.  And yes, this includes resolving symlinks.
The only other API is by dev_t, but it is highly discouraged and should
really not grow any new users.