Re: [PATCH v1 0/3] Clean up and fix error handling in mdio_mux_init()

Marc Zyngier [off-list ref] writes:

Hi Saravana,

On Wed, 04 Aug 2021 22:43:29 +0100,
Saravana Kannan [off-list ref] wrote:

quoted

This patch series was started due to -EPROBE_DEFER not being handled
correctly in mdio_mux_init() and causing issues [1]. While at it, I also
did some more error handling fixes and clean ups. The -EPROBE_DEFER fix is
the last patch.

Ideally, in the last patch we'd treat any error similar to -EPROBE_DEFER
but I'm not sure if it'll break any board/platforms where some child
mdiobus never successfully registers. If we treated all errors similar to
-EPROBE_DEFER, then none of the child mdiobus will work and that might be a
regression. If people are sure this is not a real case, then I can fix up
the last patch to always fail the entire mdio-mux init if any of the child
mdiobus registration fails.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Neil Armstrong <redacted>
Cc: Kevin Hilman <khilman@baylibre.com>
[1] - https://lore.kernel.org/lkml/CAGETcx95kHrv8wA-O+-JtfH7H9biJEGJtijuPVN0V5dUKUAB3A@mail.gmail.com/#t (local)

Saravana Kannan (3):
  net: mdio-mux: Delete unnecessary devm_kfree
  net: mdio-mux: Don't ignore memory allocation errors
  net: mdio-mux: Handle -EPROBE_DEFER correctly

 drivers/net/mdio/mdio-mux.c | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

Thanks for this. I've just gave it a go on my test platform, and this
indeed addresses the issues I was seeing [1].

Acked-by: Marc Zyngier <maz@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>

I wasn't seeing the same issues as Marc, but am heavily using everything
as modules on a few platforms using this code, and I'm not seeing any
regressions.

Thanks Saravana for finding the root cause here.

Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

Kevin