linux-kernel - Re: [PATCH] dma/pool: respect __GFP_NOWARN in dma_alloc_from

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Message-ID: <20260112081825.GC14378@unreal>
Date: Mon, 12 Jan 2026 10:18:25 +0200
From: Leon Romanovsky <leon@...nel.org>
To: Sai Sree Kartheek Adivi <s-adivi@...com>
Cc: m.szyprowski@...sung.com, robin.murphy@....com, iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org, vigneshr@...com
Subject: Re: [PATCH] dma/pool: respect __GFP_NOWARN in dma_alloc_from_pool()

On Sun, Jan 11, 2026 at 07:11:50AM +0530, Sai Sree Kartheek Adivi wrote:
> Currently, dma_alloc_from_pool() unconditionally warns and dumps a stack
> trace when an allocation fails.
> 
> This prevents callers from using the __GFP_NOWARN flag to suppress error
> messages, breaking the expectation that this flag will silence
> allocation failure logs.
> 
> Align dma_pool behaviour with other core allocators by checking for
> __GFP_NOWARN before issuing the warning.
> 
> Fixes: 9420139f516d ("dma-pool: fix coherent pool allocations for IOMMU mappings")
> Signed-off-by: Sai Sree Kartheek Adivi <s-adivi@...com>
> ---
>  kernel/dma/pool.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
> index 26392badc36b..40dc2ab9915f 100644
> --- a/kernel/dma/pool.c
> +++ b/kernel/dma/pool.c
> @@ -276,7 +276,8 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size,
>  			return page;
>  	}
>  
> -	WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
> +	if (!(gfp & __GFP_NOWARN))
> +		WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));

WARN(!(gfp & __GFP_NOWARN), "Failed to get suitable pool for %s\n", dev_name(dev));

Thanks

>  	return NULL;
>  }
>  
> -- 
> 2.34.1
> 
>