[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-Id: <20130729.005527.2071951598362619468.davem@davemloft.net>
Date: Mon, 29 Jul 2013 00:55:27 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: amirv@...lanox.com
Cc: netdev@...r.kernel.org, eugenia@...lanox.com
Subject: Re: [PATCH net-next] net/mlx4_en: Fix BlueFlame race
From: Amir Vadai <amirv@...lanox.com>
Date: Thu, 25 Jul 2013 19:21:23 +0300
> From: Eugenia Emantayev <eugenia@...lanox.com>
>
> Fix a race between BlueFlame flow and stamping in post send flow.
> Example:
> SW: Build WQE 0 on the TX buffer, except the ownership bit
> SW: Set ownership for WQE 0 on the TX buffer
> SW: Ring doorbell for WQE 0
> SW: Build WQE 1 on the TX buffer, except the ownership bit
> SW: Set ownership for WQE 1 on the TX buffer
> HW: Read WQE 0 and then WQE 1, before doorbell was rung/BF was done for WQE 1
> HW: Produce CQEs for WQE 0 and WQE 1
> SW: Process the CQEs, and stamp WQE 0 and WQE 1 accordingly (on the TX buffer)
> SW: Copy WQE 1 from the TX buffer to the BF register - ALREADY STAMPED!
> HW: CQE error with index 0xFFFF - the BF WQE's control segment is STAMPED,
> so the BF index is 0xFFFF. Error: Invalid Opcode.
> As a result QP enters the error state and no traffic can be sent.
>
> Solution:
> When stamping - do not stamp last completed wqe.
>
>
> Signed-off-by: Eugenia Emantayev <eugenia@...lanox.com>
> Signed-off-by: Amir Vadai <amirv@...lanox.com>
Applied, thanks.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists