linux-kernel - Re: [PATCH] dma/pool: eliminate alloc_pages warning in atomic_pool

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Message-ID: <8b72d722-5e68-404b-bcb0-04b7daa2a24d@arm.com>
Date: Tue, 2 Dec 2025 15:47:00 +0000
From: Robin Murphy <robin.murphy@....com>
To: Dave Kleikamp <dave.kleikamp@...cle.com>,
 Marek Szyprowski <m.szyprowski@...sung.com>
Cc: iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dma/pool: eliminate alloc_pages warning in
 atomic_pool_expand

On 2025-12-02 3:28 pm, Dave Kleikamp wrote:
> atomic_pool_expand iterately tries the allocation while decrementing the

"iteratively"?

> page order. There is no need to issue a warning if an attempted
> allocation fails.
> 
> Signed-off-by: Dave Kleikamp <dave.kleikamp@...cle.com>
> ---
>   kernel/dma/pool.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
> index ee45dee33d49..26392badc36b 100644
> --- a/kernel/dma/pool.c
> +++ b/kernel/dma/pool.c
> @@ -93,7 +93,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
>   			page = dma_alloc_from_contiguous(NULL, 1 << order,
>   							 order, false);
>   		if (!page)
> -			page = alloc_pages(gfp, order);
> +			page = alloc_pages(gfp | __GFP_NOWARN, order);

Might be nice to keep some kind of warning if we entirely fail all the 
way down to order 0, although I guess if it matters it would show up via 
the warning on dma_alloc_from_pool() failure soon enough anyway...

Either way it certainly makes sense in general;

Reviewed-by: Robin Murphy <robin.murphy@....com>

>   	} while (!page && order-- > 0);
>   	if (!page)
>   		goto out;