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Date:   Fri, 7 May 2021 08:39:21 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Anirudh Rayabharam <mail@anirudhrb.com>
Cc:     Matt Porter <mporter@kernel.crashing.org>,
        Alexandre Bounine <alex.bou9@gmail.com>,
        linux-kernel-mentees@lists.linuxfoundation.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] rapidio: fix unused variable warning in rio_cm.c
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References: <20210506181837.4758-1-mail@anirudhrb.com>
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On Thu, May 06, 2021 at 11:48:36PM +0530, Anirudh Rayabharam wrote:
> GCC produces an unused variable warning for 'rc':
> 
> 	drivers/rapidio/rio_cm.c: In function ‘rio_txcq_handler’:
> 	drivers/rapidio/rio_cm.c:673:7: warning: variable ‘rc’ set but
> 	not used [-Wunused-but-set-variable]
> 
> The return value of rio_add_outb_message() is assigned to 'rc' but it
> is never used. Fix this warning by logging an error if 'rc' is non-zero.
> 
> Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
> ---
> 
> Changes in v2:
> Log an error instead of just removing 'rc'.
> 
> v1: https://lore.kernel.org/lkml/20210501055018.9244-1-mail@anirudhrb.com/
> 
> ---
>  drivers/rapidio/rio_cm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/rapidio/rio_cm.c b/drivers/rapidio/rio_cm.c
> index 50ec53d67a4c..971a36f1a23a 100644
> --- a/drivers/rapidio/rio_cm.c
> +++ b/drivers/rapidio/rio_cm.c
> @@ -677,6 +677,11 @@ static void rio_txcq_handler(struct cm_dev *cm, int slot)
>  			cm->tx_buf[cm->tx_slot] = req->buffer;
>  			rc = rio_add_outb_message(cm->mport, req->rdev, cmbox,
>  						  req->buffer, req->len);
> +			if (rc) {
> +				riocm_error("Failed to add msg to tx queue (err=%d)",
> +						rc);

That's pretty pointless (and no need for {}).

If an error happens, properly recover from it, don't just punt and tell
the user something bad happened and then ignore it.

thanks,

greg k-h