linux-kernel - Re: [PATCH 6/6] scsi: mpt3sas: Replace a dynamic allocation with a local variable

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Message-ID: <202307281528.086CF1D063@keescook>
Date:   Fri, 28 Jul 2023 15:29:17 -0700
From:   Kees Cook <keescook@...omium.org>
To:     James Seo <james@...iv.tech>
Cc:     Sathya Prakash <sathya.prakash@...adcom.com>,
        Sreekanth Reddy <sreekanth.reddy@...adcom.com>,
        Suganath Prabu Subramani 
        <suganath-prabu.subramani@...adcom.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        MPT-FusionLinux.pdl@...adcom.com, linux-scsi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/6] scsi: mpt3sas: Replace a dynamic allocation with a
 local variable

On Tue, Jul 25, 2023 at 09:13:31AM -0700, James Seo wrote:
> This dynamic allocation can be replaced with a local variable.
> 
> Signed-off-by: James Seo <james@...iv.tech>
> ---
>  drivers/scsi/mpt3sas/mpt3sas_base.c | 19 +++++--------------
>  1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
> index cd6f36094159..a32a6fa728a7 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_base.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
> @@ -5361,10 +5361,9 @@ _base_update_diag_trigger_pages(struct MPT3SAS_ADAPTER *ioc)
>  static int _base_assign_fw_reported_qd(struct MPT3SAS_ADAPTER *ioc)
>  {
>  	Mpi2ConfigReply_t mpi_reply;
> -	Mpi2SasIOUnitPage1_t *sas_iounit_pg1 = NULL;
> +	Mpi2SasIOUnitPage1_t sas_iounit_pg1;
>  	Mpi26PCIeIOUnitPage1_t pcie_iounit_pg1;
>  	u16 depth;
> -	int sz;
>  	int rc = 0;
>  
>  	ioc->max_wideport_qd = MPT3SAS_SAS_QUEUE_DEPTH;
> @@ -5374,28 +5373,21 @@ static int _base_assign_fw_reported_qd(struct MPT3SAS_ADAPTER *ioc)
>  	if (!ioc->is_gen35_ioc)
>  		goto out;
>  	/* sas iounit page 1 */
> -	sz = offsetof(Mpi2SasIOUnitPage1_t, PhyData);
> -	sas_iounit_pg1 = kzalloc(sizeof(Mpi2SasIOUnitPage1_t), GFP_KERNEL);

Hunh. So Mpi2SasIOUnitPage1_t is used without the flexarray at all?

-Kees

> -	if (!sas_iounit_pg1) {
> -		pr_err("%s: failure at %s:%d/%s()!\n",
> -		    ioc->name, __FILE__, __LINE__, __func__);
> -		return rc;
> -	}
>  	rc = mpt3sas_config_get_sas_iounit_pg1(ioc, &mpi_reply,
> -	    sas_iounit_pg1, sz);
> +	    &sas_iounit_pg1, sizeof(Mpi2SasIOUnitPage1_t));
>  	if (rc) {
>  		pr_err("%s: failure at %s:%d/%s()!\n",
>  		    ioc->name, __FILE__, __LINE__, __func__);
>  		goto out;
>  	}
>  
> -	depth = le16_to_cpu(sas_iounit_pg1->SASWideMaxQueueDepth);
> +	depth = le16_to_cpu(sas_iounit_pg1.SASWideMaxQueueDepth);
>  	ioc->max_wideport_qd = (depth ? depth : MPT3SAS_SAS_QUEUE_DEPTH);
>  
> -	depth = le16_to_cpu(sas_iounit_pg1->SASNarrowMaxQueueDepth);
> +	depth = le16_to_cpu(sas_iounit_pg1.SASNarrowMaxQueueDepth);
>  	ioc->max_narrowport_qd = (depth ? depth : MPT3SAS_SAS_QUEUE_DEPTH);
>  
> -	depth = sas_iounit_pg1->SATAMaxQDepth;
> +	depth = sas_iounit_pg1.SATAMaxQDepth;
>  	ioc->max_sata_qd = (depth ? depth : MPT3SAS_SATA_QUEUE_DEPTH);
>  
>  	/* pcie iounit page 1 */
> @@ -5414,7 +5406,6 @@ static int _base_assign_fw_reported_qd(struct MPT3SAS_ADAPTER *ioc)
>  	    "MaxWidePortQD: 0x%x MaxNarrowPortQD: 0x%x MaxSataQD: 0x%x MaxNvmeQD: 0x%x\n",
>  	    ioc->max_wideport_qd, ioc->max_narrowport_qd,
>  	    ioc->max_sata_qd, ioc->max_nvme_qd));
> -	kfree(sas_iounit_pg1);
>  	return rc;
>  }
>  
> -- 
> 2.39.2
> 

-- 
Kees Cook