Re: [PATCH] net: macb: fix ignored return value of clk_prepare_enable() in runtime resume

[Gustavo Kenji]

Hi Théo,

Thanks for the review.

> Your CC list is lacking some net maintainers, how did you get who to
> send this email to?

You're right, and I apologize. I did run get_maintainer.pl, but I made a
mistake assembling the --to/--cc lists and dropped the networking
maintainers. The full output is:

  Théo Lebrun <theo.lebrun@xxxxxxxxxxx>      (macb maintainer)
  Conor Dooley <conor.dooley@xxxxxxxxxxxxx>  (reviewer)
  Andrew Lunn <andrew+netdev@xxxxxxx>        (netdev)
  David S. Miller <davem@xxxxxxxxxxxxx>
  Eric Dumazet <edumazet@xxxxxxxxxx>
  Jakub Kicinski <kuba@xxxxxxxxxx>
  Paolo Abeni <pabeni@xxxxxxxxxx>
  netdev@xxxxxxxxxxxxxxx
  linux-kernel@xxxxxxxxxxxxxxx

I'll Cc all of them in v2.

> Could you point out if this was figured out to address a bug or if it
> is only a theoretical defense?

It is not tied to an observed failure. I found it by code review and I do
not have macb hardware to test on, so this is a robustness fix rather
than a bug fix: clk_prepare_enable() is __must_check, and here its return
value is silently discarded in the runtime-resume path. If you feel this
isn't worth changing, I'm fine with dropping the patch.

> "atomically" usually refers to some locking mechanism [...]

That was a poor word choice on my part; there is no locking involved. I
meant only that clk_bulk_prepare_enable() enables the clocks as a group
and, on failure, unwinds the ones it already enabled. I've dropped
"atomically" and reworded the commit message in v2.

Thanks,
Gustavo