Re: [PATCH v2 06/33] ibmvfc: add NVMe/FC protocol interface definitions

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] ABI breakage in legacy SCSI implicit logout MAD length
--

--- Patch [6]: [PATCH v2 06/33] ibmvfc: add NVMe/FC protocol interface definitions ---
commit ed7fd173b2f77c91dcd53e86ac17a531e4649515
Author: Tyrel Datwyler <tyreld@linux.ibm.com>

ibmvfc: add NVMe/FC protocol interface definitions

This commit adds the protocol definitions for client-VIOS interface updates
needed to support NVMe/FC over the ibmvfc NPIV transport. It extends the
ibmvfc interface with NVMe/FC-specific capability bits, opcodes, channel
definitions, and v3 command layout support.

> diff --git a/drivers/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h
> index 0e259e9d2e9bb..f8a2bf92da410 100644
> --- a/drivers/scsi/ibmvscsi/ibmvfc.h
> +++ b/drivers/scsi/ibmvscsi/ibmvfc.h

[ ... ]

> @@ -377,20 +419,27 @@ struct ibmvfc_query_tgt {
>  struct ibmvfc_implicit_logout {
>  	struct ibmvfc_mad_common common;
>  	__be64 old_scsi_id;
> -	__be64 reserved[2];
> +	__be64 reserved[8];
> +	__be64 target_wwpn;
>  } __packed __aligned(8);

[Severity: High]
Does this change break ABI compatibility with older VIOS firmware for legacy
SCSI logouts?

The size of this structure increases from 48 bytes to 104 bytes. When
tearing down a target, the existing code in the driver uses sizeof() to set
the MAD length:

drivers/scsi/ibmvscsi/ibmvfc.c:__ibmvfc_tgt_get_implicit_logout_evt() {
    ...
    mad->common.length = cpu_to_be16(sizeof(*mad));
    ...
}

Since this length is sent for the existing IBMVFC_IMPLICIT_LOGOUT (0x0040)
opcode, will older VIOS firmware reject the 104-byte request as malformed,
leading to target resource leaks?

Additionally, it appears target_wwpn is never populated with the target's
WWPN in this path. Would newer VIOS firmware that recognizes the larger MAD
also reject the request due to the zeroed WWPN field?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723000149.969416-1-tyreld@linux.ibm.com?part=6