Re: [PATCH v5 43/56] scsi: qla2xxx: Use 64-bit FPM word counters for 29xx host stats

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The patch introduces corrupted RX/TX word counter reporting for QLA29XX hardware on big-endian architectures due to a double byte-swap bug.
--

--- Patch [43]: [PATCH v5 43/56] scsi: qla2xxx: Use 64-bit FPM word counters for 29xx host stats ---
commit 6dc53192ab6558b115cab1a52a856c1edbdfd7e4
Author: Nilesh Javali <njavali@marvell.com>

scsi: qla2xxx: Use 64-bit FPM word counters for 29xx host stats

This patch adds IS_QLA29XX() to the high-speed branch in
qla2x00_get_fc_host_stats() so that 29xx reports hardware word counters
instead of falling back to software approximations.

> diff --git a/drivers/scsi/qla2xxx/qla_attr.c b/drivers/scsi/qla2xxx/qla_attr.c
> index 19aa66b8ca521..6cf74f8c9628d 100644
> --- a/drivers/scsi/qla2xxx/qla_attr.c
> +++ b/drivers/scsi/qla2xxx/qla_attr.c
> @@ -2990,7 +2990,8 @@ qla2x00_get_fc_host_stats(struct Scsi_Host *shost)
>  		p->error_frames =
>  		    le32_to_cpu(stats->dropped_frames) +
>  		    le32_to_cpu(stats->discarded_frames);
> -		if (IS_QLA83XX(ha) || IS_QLA27XX(ha) || IS_QLA28XX(ha)) {
> +		if (IS_QLA83XX(ha) || IS_QLA27XX(ha) || IS_QLA28XX(ha) ||
> +		    IS_QLA29XX(ha)) {
>  			p->rx_words = le64_to_cpu(stats->fpm_recv_word_cnt);

[Severity: Medium]
Will this result in corrupted RX/TX word counters for QLA29XX on big-endian
systems?

The link_statistics DMA buffer is globally byte-swapped in-place as 32-bit
integers by le32_to_cpus() in qla24xx_get_isp_stats():

drivers/scsi/qla2xxx/qla_mbx.c:qla24xx_get_isp_stats() {
    ...
    /* Re-endianize - firmware data is le32. */
    for ( ; dwords--; iter++)
        le32_to_cpus(iter);
    ...
}

For 64-bit fields like fpm_recv_word_cnt, this independently swaps the two
32-bit halves.

Later, this code calls le64_to_cpu() on the result, which effectively jumbles
the 8 bytes into an invalid sequence on big-endian machines.

While this double-swap logic seems to be a pre-existing flaw for older
adapters (83xx/27xx/28xx), this patch specifically introduces the bug for
QLA29XX by disabling its previously working software-based fallback metric
and routing it into the broken hardware reading path.

>  			p->tx_words = le64_to_cpu(stats->fpm_xmit_word_cnt);
>  		} else {
>  			p->rx_words = ib >> 2;
>  			p->tx_words = ob >> 2;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260717152904.3155730-1-njavali@marvell.com?part=43