Re: [PATCH 17/23] proc: add a read_iter method to proc proc_ops

[Al Viro]

On Wed, Jul 01, 2020 at 10:09:45PM +0200, Christoph Hellwig wrote:
> This will allow proc files to implement iter read semantics.

*UGH*

You are introducing file_operations with both ->read() and ->read_iter();
worse, in some cases they are not equivalent.  Sure, ->read() takes
precedence right now, but...  why not a separate file_operations for
->read_iter-capable files?

I really hate the fallbacks of that sort - they tend to be brittle
as hell.  And while we are at it, I'm not sure that your iter_read() 
has good cause to be non-static.