[PATCH for-5.4 0/2] scsi: qla2xxx: Fix P2P mode

[Sasha Levin]

On Thu, Apr 15, 2021 at 10:51:42PM +0300, Anastasia Kovaleva wrote:
>Hi Greg and Sasha,
>
>QLogic FC adapters don’t work in P2P mode on the latest stable 5.4 (at least
>QLE2692, and QLE2694, QLE2742 are affected).
>
>We’ve tested and bisected from 5.4 up to 5.4.112 and figured out the
>following:

>
>1. From 5.4 to 5.4.5 inclusively direct mode doesn’t work at all.
>
>   Stable commit a82545b62e07 ("scsi: qla2xxx: Change discovery state before
>   PLOGI") fixes the issue in 5.4.6
>
>2. From 5.4.6 to 5.4.68 inclusively direct mode works but FC link cannot be
>   recovered after issue_lip and all presented LUNs are lost
>
>   Not working issue_lip is an outcome of a82545b62e07 applied to stable
>   without the upstream commit 65e920093805 ("scsi: qla2xxx: Fix device connect
>   issues in P2P configuration.").
>
>3. From 5.4.69 up till now (5.4.112) direct mode doesn’t work again
>
>   The issue was introduced by stable commit 74924e407bf7 ("scsi: qla2xxx:
>   Retry PLOGI on FC-NVMe PRLI failure").
>
>   Upstream commit 84ed362ac40c ("scsi: qla2xxx: Dual FCP-NVMe target port
>   support") fixes the issue.
>
>So, in order to fix both P2P issues we need to apply upstream commits
>65e920093805 and 84ed362ac40c.

That's a great analysis, thank you.

>However, stable commits 0b84591fdd5e ("scsi: qla2xxx: Fix stuck login session
>using prli_pend_timer") introduced in 5.4.19 and 74924e407bf7 ("scsi: qla2xxx:
>Retry PLOGI on FC-NVMe PRLI failure") in 5.4.69 were applied in the wrong
>order, upstream and chronological-wise with regards to required upstream fixes,
>and cherry-picking of the fixes is not possible without a merge conflict.

Right, in particular: 74924e407bf7 ("scsi: qla2xxx: Retry PLOGI on
FC-NVMe PRLI failure") was modified to work around missing 84ed362ac40c
("scsi: qla2xxx: Dual FCP-NVMe target port support"), which is where the
rest of the conflicts are coming from.

>The series provides merge conflict resolution and resolves both P2P discovery
>and issue_lip issue. It has been tested over Linux stable 5.4.112 and
>Ubuntu 20.04 kernel 5.4.0-71.79 (that's based off stable 5.4.101).
>
>Please apply at your earliest convenience to 5.4 stable.

So instead of applying even more modified patches that'll create similar
issue in the future, I backed up 0b84591fdd5e and 74924e407bf7, and
applied the 4 commits you've pointed out in the "correct" order. I also
grabbed 27258a577144 ("scsi: qla2xxx: Add a shadow variable to hold
disc_state history of fcport") for completeness.

Thanks for diagnosing this issue! Please let me know if something is
still broken.

-- 
Thanks,
Sasha