-----Original Message-----
From: Doug Anderson <dianders@chromium.org>
Sent: Wednesday, October 28, 2020 8:07 PM
To: Rakesh Pillai <redacted>
Cc: ath10k <redacted>; linux-wireless <linux-
wireless@vger.kernel.org>; LKML [off-list ref]; Abhishek
Kumar [off-list ref]; Brian Norris [off-list ref]
Subject: Re: [PATCH] ath10k: Fix the parsing error in service available event

Hi,

On Tue, Oct 27, 2020 at 8:20 AM Rakesh Pillai [off-list ref]
wrote:

quoted

The wmi service available event has been
extended to contain extra 128 bit for new services
to be indicated by firmware.

Currently the presence of any optional TLVs in
the wmi service available event leads to a parsing
error with the below error message:
ath10k_snoc 18800000.wifi: failed to parse svc_avail tlv: -71

The wmi service available event parsing should
not return error for the newly added optional TLV.
Fix this parsing for service available event message.

Tested-on: WCN3990 hw1.0 SNOC

Signed-off-by: Rakesh Pillai <redacted>
---
 drivers/net/wireless/ath/ath10k/wmi-tlv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/wmi-tlv.c

b/drivers/net/wireless/ath/ath10k/wmi-tlv.c

quoted

index 932266d..3b49e29 100644

--- a/drivers/net/wireless/ath/ath10k/wmi-tlv.c
+++ b/drivers/net/wireless/ath/ath10k/wmi-tlv.c

@@ -1404,9 +1404,12 @@ static int ath10k_wmi_tlv_svc_avail_parse(struct

ath10k *ar, u16 tag, u16 len,

quoted

                arg->service_map_ext_len = *(__le32 *)ptr;
                arg->service_map_ext = ptr + sizeof(__le32);
                return 0;
+       case WMI_TLV_TAG_FIRST_ARRAY_ENUM:
+               return 0;

This is at least slightly worrying to me.  If I were calling this
function, I'd expect that if I didn't get back an error that at least
"arg->service_map_ext_len" was filled in.  Seems like you should do:

case WMI_TLV_TAG_FIRST_ARRAY_ENUM:
  arg->service_map_ext_len = 0;
  arg->service_map_ext = NULL;
  return 0;

...and maybe add a comment about why you're doing that?

At the moment things are working OK because
ath10k_wmi_event_service_available() happens to init the structure to
0 before calling with:

  struct wmi_svc_avail_ev_arg arg = {};

....but it doesn't seem like a great idea to rely on that.

That all being said, I'm just a drive-by reviewer and if everyone else
likes it the way it is, feel free to ignore my comments.

Hi Doug,

The TLV TAG " WMI_TLV_TAG_STRUCT_SERVICE_AVAILABLE_EVENT" is the first and a mandatory TLV in the service available event.
The subsequent TLVs are optional ones and may or may not be present (based on FW versions).
This patch just fixes the bug, where the presence of any other TLVs are leading to a failure in parsing the service available msg.
If, in future, we plan to use any other services from firmware, which is exposed in the extended TLVs, we will need to add a new variable (and not service_map_ext) to set the service.

-Doug