[PATCH v3 1/1] nvme-pci : Fix EEH failure on ppc after subsystem reset

[Maurizio Lombardi]

út 4. 6. 2024 v 11:16 odesílatel Nilay Shroff <nilay at linux.ibm.com> napsal:
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index f5d150c62955..afb8419566a9 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -562,6 +562,7 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
>                 switch (old_state) {
>                 case NVME_CTRL_NEW:
>                 case NVME_CTRL_LIVE:
> +               case NVME_CTRL_CONNECTING:
>                         changed = true;
>                         fallthrough;
>                 default:

Side note:

I believe this could fix a race condition in the nvme-tcp driver.
Some time ago we received a kernel dump where the controller was
flagged as NVME_CTRL_LIVE but the sockets were marked as TCP_CLOSED,
the kernel was hanging into io_work.
It might be possible that the socket's nvme_tcp_error_recovery
callback was executed while the ctrl was still marked as
NVME_CTRL_CONNECTING, nvme_change_ctrl_state() doesn't allow a
reconnecting controller to switch to the resetting state and therefore
nvme_tcp_error_recovery() simply returns without triggering an error
recovery.

nvme_tcp_setup_ctrl() then moves the ctrl to the LIVE state, but with
closed tcp sockets.

I guess that this change would fix the possible race condition, even
if I am not completely sure what could happen in case of a race
between nvme_tcp_setup_ctrl() and the error recovery code.

Maurizio