Re: [PATCH v3 2/2] net: cdc_ncm: respect operator preferred MTU reported by MBIM

Ben Chan [off-list ref] writes:

According to "Universal Serial Bus Communications Class Subclass
Specification for Mobile Broadband Interface Model, Revision 1.0,
Errata-1" published by USB-IF, the wMTU field of the MBIM extended
functional descriptor indicates the operator preferred MTU for IP data
streams.

This patch modifies cdc_ncm_setup to ensure that the MTU value set on
the usbnet device does not exceed the operator preferred MTU indicated
by wMTU if the MBIM device exposes a MBIM extended functional
descriptor.

Signed-off-by: Ben Chan <redacted>
---
Patch v3 (which is same as v2) adds the le16_to_cpu conversion on
ctx->mbim_extended_desc->wMTU as pointed out and suggested by
'Bjørn Mork [off-list ref]'.

Looks good to me FWIW.

I was worried that I might have created a merge conflict here by posting
the unrelated cdc_ncm fix, touching the same function.  But we're in
luck: That fix and your patch applies cleanly on top of each other in
any order.


Bjørn