linux-kernel - Re: [PATCH] drivers/scsi/ipr.c: reorder error handling code to include iounmap

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Date:	Tue, 14 Jun 2011 11:09:32 -0500
From:	Brian King <brking@...ux.vnet.ibm.com>
To:	Wayne Boyer <wayneb@...ux.vnet.ibm.com>
CC:	Julia Lawall <julia@...u.dk>, Brian King <brking@...ibm.com>,
	kernel-janitors@...r.kernel.org,
	"James E.J. Bottomley" <JBottomley@...allels.com>,
	linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drivers/scsi/ipr.c: reorder error handling code to include
 iounmap

On 06/09/2011 10:51 AM, Wayne Boyer wrote:
> On 05/31/2011 07:16 AM, Julia Lawall wrote:
>> From: Julia Lawall <julia@...u.dk>
>>
>> The out_msi_disable label should be before cleanup_nomem to additionally
>> benefit from the call to iounmap.
> 
> Yes, this is a problem.  I propose the following patch instead.

By removing the out_msi_disable label, if you fail initialization later
on and goto cleanup_nomem, you will end up leaving MSI enabled when you exit
with this patch.

-Brian



> 
> ---
> 
> In the case where ipr_test_msi returns an error that is not -EOPNOTSUPP, the
> execution jumps to the out_msi_disable label.  This misses the call to iounmap
> for ipr_regs which was initialized earlier.
> 
> The fix is to do the call to pci_disable_msi when the error case is detected
> and then goto the cleanup_nomem label if the error is not -EOPNOTSUPP.
> 
> Signed-off-by: Wayne Boyer <wayneb@...ux.vnet.ibm.com>
> ---
> 
>  drivers/scsi/ipr.c |   10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> Index: b/drivers/scsi/ipr.c
> ===================================================================
> --- a/drivers/scsi/ipr.c        2011-06-09 08:14:44.927740117 -0700
> +++ b/drivers/scsi/ipr.c        2011-06-09 08:50:10.105630466 -0700
> @@ -8763,11 +8763,11 @@ static int __devinit ipr_probe_ioa(struc
>         /* Enable MSI style interrupts if they are supported. */
>         if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSI && !pci_enable_msi(pdev)) {
>                 rc = ipr_test_msi(ioa_cfg, pdev);
> -               if (rc == -EOPNOTSUPP)
> +               if (rc) {
>                         pci_disable_msi(pdev);
> -               else if (rc)
> -                       goto out_msi_disable;
> -               else
> +                       if (rc != -EOPNOTSUPP)
> +                               goto cleanup_nomem;
> +               } else
>                         dev_info(&pdev->dev, "MSI enabled with IRQ: %d\n", pdev->irq);
>         } else if (ipr_debug)
>                 dev_info(&pdev->dev, "Cannot enable MSI.\n");
> @@ -8847,8 +8847,6 @@ cleanup_nolog:
>         ipr_free_mem(ioa_cfg);
>  cleanup_nomem:
>         iounmap(ipr_regs);
> -out_msi_disable:
> -       pci_disable_msi(pdev);
>  out_release_regions:
>         pci_release_regions(pdev);
>  out_scsi_host_put:
> 
> 


-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center


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