linux-kernel - Re: [PATCH] swiotlb: Clean up reporting

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Date:   Wed, 11 Jul 2018 15:16:11 -0400
From:   Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     linux-kernel@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>,
        iommu@...ts.linux-foundation.org
Subject: Re: [PATCH] swiotlb: Clean up reporting

On Tue, Jul 10, 2018 at 04:22:22PM -0700, Kees Cook wrote:
> This removes needless use of '%p', and refactors the printk calls to
> use pr_*() helpers instead.
> 
> Signed-off-by: Kees Cook <keescook@...omium.org>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>

Christoph, volunteered to pick this patch up in his tree. Thank you!
> ---
>  kernel/dma/swiotlb.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 904541055792..4f8a6dbf0b60 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -17,6 +17,8 @@
>   * 08/12/11 beckyb	Add highmem support
>   */
>  
> +#define pr_fmt(fmt) "software IO TLB: " fmt
> +
>  #include <linux/cache.h>
>  #include <linux/dma-direct.h>
>  #include <linux/mm.h>
> @@ -162,20 +164,16 @@ static bool no_iotlb_memory;
>  void swiotlb_print_info(void)
>  {
>  	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
> -	unsigned char *vstart, *vend;
>  
>  	if (no_iotlb_memory) {
> -		pr_warn("software IO TLB: No low mem\n");
> +		pr_warn("No low mem\n");
>  		return;
>  	}
>  
> -	vstart = phys_to_virt(io_tlb_start);
> -	vend = phys_to_virt(io_tlb_end);
> -
> -	printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n",
> +	pr_info("mapped [mem %#010llx-%#010llx] (%luMB)\n",
>  	       (unsigned long long)io_tlb_start,
>  	       (unsigned long long)io_tlb_end,
> -	       bytes >> 20, vstart, vend - 1);
> +	       bytes >> 20);
>  }
>  
>  /*
> @@ -275,7 +273,7 @@ swiotlb_init(int verbose)
>  	if (io_tlb_start)
>  		memblock_free_early(io_tlb_start,
>  				    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
> -	pr_warn("Cannot allocate SWIOTLB buffer");
> +	pr_warn("Cannot allocate buffer");
>  	no_iotlb_memory = true;
>  }
>  
> @@ -317,8 +315,8 @@ swiotlb_late_init_with_default_size(size_t default_size)
>  		return -ENOMEM;
>  	}
>  	if (order != get_order(bytes)) {
> -		printk(KERN_WARNING "Warning: only able to allocate %ld MB "
> -		       "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
> +		pr_warn("only able to allocate %ld MB\n",
> +			(PAGE_SIZE << order) >> 20);
>  		io_tlb_nslabs = SLABS_PER_PAGE << order;
>  	}
>  	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
> -- 
> 2.17.1
> 
> 
> -- 
> Kees Cook
> Pixel Security