linux-kernel - Re: [PATCH] char: xillybus: use devm_add_action_or

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Date:	Tue, 26 Apr 2016 13:23:08 +0300
From:	Eli Billauer <eli.billauer@...il.com>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] char: xillybus: use devm_add_action_or_reset

Thanks,

I like the direction, however both xilly_map_single_* functions turn out 
ending with

     if (rc)
         return rc;

     return 0;

Which is equivalent to just "return rc". Or maybe return the value of 
the devm_add_action_or_reset() call directly, and remove the "rc" 
variable? I don't know which one is better coding style.

Could you please take care of that and resubmit? Just want to save 
ourselves another patch that fixes this.

Regards,
    Eli


On 25/04/16 23:51, Sudip Mukherjee wrote:
> If devm_add_action() fails we are explicitly calling dma_unmap_single()
> and kfree(). Lets use the helper devm_add_action_or_reset() and return
> directly in case of error, as we know that the cleanup function has been
> already called by the helper if there was any error.
>
> Signed-off-by: Sudip Mukherjee<sudip.mukherjee@...ethink.co.uk>
> ---
>   drivers/char/xillybus/xillybus_of.c   | 7 ++-----
>   drivers/char/xillybus/xillybus_pcie.c | 7 ++-----
>   2 files changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/char/xillybus/xillybus_of.c b/drivers/char/xillybus/xillybus_of.c
> index 7818650..17f45b6 100644
> --- a/drivers/char/xillybus/xillybus_of.c
> +++ b/drivers/char/xillybus/xillybus_of.c
> @@ -101,13 +101,10 @@ static int xilly_map_single_of(struct xilly_endpoint *ep,
>
>   	*ret_dma_handle = addr;
>
> -	rc = devm_add_action(ep->dev, xilly_of_unmap, this);
> +	rc = devm_add_action_or_reset(ep->dev, xilly_of_unmap, this);
>
> -	if (rc) {
> -		dma_unmap_single(ep->dev, addr, size, direction);
> -		kfree(this);
> +	if (rc)
>   		return rc;
> -	}
>
>   	return 0;
>   }
> diff --git a/drivers/char/xillybus/xillybus_pcie.c b/drivers/char/xillybus/xillybus_pcie.c
> index 9418300..99c688f 100644
> --- a/drivers/char/xillybus/xillybus_pcie.c
> +++ b/drivers/char/xillybus/xillybus_pcie.c
> @@ -120,12 +120,9 @@ static int xilly_map_single_pci(struct xilly_endpoint *ep,
>
>   	*ret_dma_handle = addr;
>
> -	rc = devm_add_action(ep->dev, xilly_pci_unmap, this);
> -	if (rc) {
> -		pci_unmap_single(ep->pdev, addr, size, pci_direction);
> -		kfree(this);
> +	rc = devm_add_action_or_reset(ep->dev, xilly_pci_unmap, this);
> +	if (rc)
>   		return rc;
> -	}
>
>   	return 0;
>   }
>