linux-kernel - Re: [PATCH] bnx2fc: Fix locking requirements in bnx2fc_init

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Date:	Tue, 5 Apr 2016 13:43:20 -0400
From:	Chad Dupuis <chad.dupuis@...gic.com>
To:	Bastien Philbert <bastienphilbert@...il.com>
CC:	<QLogic-Storage-Upstream@...gic.com>, <jejb@...ux.vnet.ibm.com>,
	<martin.petersen@...cle.com>, <linux-scsi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] bnx2fc: Fix locking requirements in bnx2fc_init_tgt



On Tue, 5 Apr 2016, Bastien Philbert wrote:

> This fixes the locking around the call to bnx2fc_alloc_id to comply
> with the comments about this particular function's definition about
> requiring the need to hold the hba mutex before and after calling
> it.
> Signed-off-by: Bastien Philbert <bastienphilbert@...il.com>
> ---
> drivers/scsi/bnx2fc/bnx2fc_tgt.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/bnx2fc/bnx2fc_tgt.c b/drivers/scsi/bnx2fc/bnx2fc_tgt.c
> index 08ec318..f2988cd 100644
> --- a/drivers/scsi/bnx2fc/bnx2fc_tgt.c
> +++ b/drivers/scsi/bnx2fc/bnx2fc_tgt.c
> @@ -368,9 +368,13 @@ static int bnx2fc_init_tgt(struct bnx2fc_rport *tgt,
> 		return -1;
> 	}
>
> +	mutex_lock(&hba->hba_mutex);
> 	tgt->fcoe_conn_id = bnx2fc_alloc_conn_id(hba, tgt);
> -	if (tgt->fcoe_conn_id == -1)
> +	if (tgt->fcoe_conn_id == -1) {
> +		mutex_unlock(&hba->hba_mutex);
> 		return -1;
> +	}
> +	mutex_unlock(&hba->hba_mutex);
>
> 	BNX2FC_TGT_DBG(tgt, "init_tgt - conn_id = 0x%x\n", tgt->fcoe_conn_id);
>
>

Taking the mutex here is not needed as it is already taken in 
bnx2fc_rport_event_handler() in the call chain 
bnx2fc_rport_event_handler->bnx2fc_offload_session->bnx2fc_init_tgt->bnx2fc_alloc_conn_id