linux-kernel - Re: [PATCH 1/2] PCI: endpoint: Clean up error handling in vpci_scan

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Message-ID: <d8f510d1-db05-66a8-b379-464fdc817143@linux.intel.com>
Date: Fri, 14 Jun 2024 15:57:49 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
cc: Frank Li <Frank.Li@....com>, Jon Mason <jdmason@...zu.us>, 
    Dave Jiang <dave.jiang@...el.com>, Allen Hubbe <allenbh@...il.com>, 
    Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>, 
    Krzysztof Wilczyński <kw@...ux.com>, 
    Kishon Vijay Abraham I <kishon@...nel.org>, 
    Bjorn Helgaas <bhelgaas@...gle.com>, ntb@...ts.linux.dev, 
    linux-pci@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>, 
    kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 1/2] PCI: endpoint: Clean up error handling in
 vpci_scan_bus()

On Mon, 10 Jun 2024, Dan Carpenter wrote:

> Smatch complains about inconsistent NULL checking in vpci_scan_bus():
> 
>     drivers/pci/endpoint/functions/pci-epf-vntb.c:1024 vpci_scan_bus()
>     error: we previously assumed 'vpci_bus' could be null (see line 1021)
> 
> Instead of printing an error message and then crashing we should return
> an error code and clean up.  Also the NULL check is reversed so it
> prints an error for success instead of failure.
> 
> Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
> ---
>  drivers/pci/endpoint/functions/pci-epf-vntb.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> index 8e779eecd62d..7f05a44e9a9f 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> @@ -1018,8 +1018,10 @@ static int vpci_scan_bus(void *sysdata)
>  	struct epf_ntb *ndev = sysdata;
>  
>  	vpci_bus = pci_scan_bus(ndev->vbus_number, &vpci_ops, sysdata);
> -	if (vpci_bus)
> -		pr_err("create pci bus\n");
> +	if (!vpci_bus) {
> +		pr_err("create pci bus failed\n");
> +		return -EINVAL;
> +	}
>  
>  	pci_bus_add_devices(vpci_bus);
>  
> @@ -1338,10 +1340,14 @@ static int epf_ntb_bind(struct pci_epf *epf)
>  		goto err_bar_alloc;
>  	}
>  
> -	vpci_scan_bus(ntb);
> +	ret = vpci_scan_bus(ntb);
> +	if (ret)
> +		goto err_unregister;
>  
>  	return 0;
>  
> +err_unregister:
> +	pci_unregister_driver(&vntb_pci_driver);
>  err_bar_alloc:
>  	epf_ntb_config_spad_bar_free(ntb);

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>


-- 
 i.