linux-kernel - Re: [PATCH RESEND] bnx2fc:Fix locking requirements before calling the function bnx2fc_alloc_conn

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Date:	Mon, 18 Jan 2016 12:47:06 -0500
From:	Chad Dupuis <chad.dupuis@...gic.com>
To:	Nicholas Krause <xerofoify@...il.com>
CC:	<QLogic-Storage-Upstream@...gic.com>,
	<James.Bottomley@...senPartnership.com>,
	<martin.petersen@...cle.com>, <linux-scsi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] bnx2fc:Fix locking requirements before calling
 the function bnx2fc_alloc_conn_id



On Thu, 14 Jan 2016, Nicholas Krause wrote:

> This fixes the locking requirements before calling the function
> bnx2fc_alloc_conn_id by locking the mutex hba_mutex of the
> structure pointer hba in the function bnx2fc_init_tgt as this
> is commented as required to be held by the caller of the function
> bnx2fc_alloc_conn_id. In addition we must also unlock this lock if
> either a error occurs inside the function bnx2fc_alloc_conn_id or
> this function exits successfully in order to avoid deadlock with
> other users of this mutex.
>
> Signed-off-by: Nicholas Krause <xerofoify@...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 c66c708..41fec79 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);
>
>

Nack, hba->hba_mutex is already taken in the bnx2fc_alloc_conn_id() so 
there is no need to take it in the caller.