-----Original Message-----
From: Mike Christie [mailto:micha...@cs.wisc.edu]
Sent: Thursday, May 08, 2014 3:49 AM
To: Jay Kallickal
Cc: jbottom...@parallels.com; linux-scsi@vger.kernel.org; Jayamohan Kallickal;
Minh Duc Tran; Sony John-N
Subject: Re: [PATCH 7/8] be2iscsi: Fix processing cqe for cxn whose endpoint is
freed
On 05/05/2014 08:41 PM, Jay Kallickal wrote:
> From: Jayamohan Kallickal <jayamohan.kallic...@emulex.com>
>
> During heavy IO in multipath environment with many active sessions
> and port-bouncing happening, there is a race condition because of
> which beiscsi_prcess_cqe() gets called for a connection whose
> endpoint is freed.
>
> Checking endpoint reference for a connection before processing in
> beiscsi_process_cq().
>
> Signed-off-by: Minh Tran <minhduc.t...@emulex.com>
> Signed-off-by: John Soni Jose <sony.joh...@emulex.com>
> Signed-off-by: Jayamohan Kallickal <jayamohan.kallic...@emulex.com>
> ---
> drivers/scsi/be2iscsi/be_main.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/scsi/be2iscsi/be_main.c
> b/drivers/scsi/be2iscsi/be_main.c index dccda6c..5a7022f 100644
> --- a/drivers/scsi/be2iscsi/be_main.c
> +++ b/drivers/scsi/be2iscsi/be_main.c
> @@ -2110,6 +2110,16 @@ static unsigned int beiscsi_process_cq(struct
> be_eq_obj *pbe_eq)
>
> cri_index = BE_GET_CRI_FROM_CID(cid);
> ep = phba->ep_array[cri_index];
> + if (unlikely(ep == NULL)) {
> + /* connection has already been freed
> + * just move on to next one
> + */
> + beiscsi_log(phba, KERN_WARNING,
> + BEISCSI_LOG_INIT,
> + "BM_%d : proc cqe of disconn ep: cid %d\n",
> + cid);
> + goto proc_next_cqe;
> + }
> beiscsi_ep = ep->dd_data;
> beiscsi_conn = beiscsi_ep->conn;
>
> It looks like if that race is possible then we could also free the ep while
> you are accessing right? I think you would need to get a ref to the ep.
We will pull out this patch from this release. This is a very corner case and
requires changes to be done in the IO path of the driver. We will redo the
patch and submit in our next release.
Please pull-in all the other patches in this set expect this particular one
"[PATCH 7/8] be2iscsi: Fix processing cqe for cxn whose endpoint is freed".
> What command/function tells the card to stop sending the driver
> events/notifications/ios for that connection? Is it beiscsi_close_conn or
> mgmt_invalidate_connection?
Mgmt_invalidate_connection tell card to stop sending events to the driver for a
particular connection.
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