linux-kernel - Re: [PATCH 1/2] swiotlb: Rate-limit printing when running out of SW-IOMMU space

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Date:   Sat, 5 Nov 2016 15:40:19 -0400
From:   Konrad Rzeszutek Wilk <konrad@...nok.org>
To:     Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Jonathan Corbet <corbet@....net>,
        Magnus Damm <magnus.damm@...il.com>,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        iommu@...ts.linux-foundation.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH 1/2] swiotlb: Rate-limit printing when running out of
 SW-IOMMU space

On Mon, Oct 31, 2016 at 04:45:03PM +0100, Geert Uytterhoeven wrote:
> If the system runs out of SW-IOMMU space, changes are high successive
> requests will fail, too, flooding the kernel log.  This is true
> especially for streaming DMA, which is typically used repeatedly outside
> the driver's initialization routine.  Add rate-limiting to fix this.
> 
> While at it, get rid of the open-coded dev_name() handling by using the
> appropriate dev_err_*() variant.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>

applied.
> ---
>  lib/swiotlb.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> index 22e13a0e19d76a2b..6ce764410ae475cc 100644
> --- a/lib/swiotlb.c
> +++ b/lib/swiotlb.c
> @@ -714,8 +714,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
>  	 * When the mapping is small enough return a static buffer to limit
>  	 * the damage, or panic when the transfer is too big.
>  	 */
> -	printk(KERN_ERR "DMA: Out of SW-IOMMU space for %zu bytes at "
> -	       "device %s\n", size, dev ? dev_name(dev) : "?");
> +	dev_err_ratelimited(dev, "DMA: Out of SW-IOMMU space for %zu bytes\n",
> +			    size);
>  
>  	if (size <= io_tlb_overflow || !do_panic)
>  		return;
> -- 
> 1.9.1
>