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From: Damien Le Moal <dlemoal@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Yihang Li <liyihang9@huawei.com>,
	John Garry <john.g.garry@oracle.com>,
	yanaijie@huawei.com, jejb@linux.ibm.com,
	martin.petersen@oracle.com, chenxiang66@hisilicon.com,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linuxarm@huawei.com, prime.zeng@huawei.com,
	yangxingui@huawei.com
Subject: Re: [PATCH v2] scsi: libsas: Allocation SMP request is aligned to ARCH_DMA_MINALIGN
Date: Thu, 28 Mar 2024 16:36:12 +0900	[thread overview]
Message-ID: <ba7d201b-3746-4ee1-9574-5782cccbc88e@kernel.org> (raw)
In-Reply-To: <ZgUcTLQnoLuqhOxO@infradead.org>

On 3/28/24 16:29, Christoph Hellwig wrote:
> On Thu, Mar 28, 2024 at 04:23:22PM +0900, Damien Le Moal wrote:
>> But I thought that the original issue was that some arch have ARCH_DMA_MINALIGN
>> down to 8B but hisi driver needs at least 16 ?
>>
>> So in the end, you need something like:
>>
>> 	size = ALIGN(size, max(16, ARCH_DMA_MINALIGN));
>>
>> no ?
> 
> I don't think we ever have an 8 byte dma minalign.  With 8-byte
> aligned addresses dma_mapping_error could run into problems.

My bad: it is kmalloc() that can return something aligned to 8B...
So "size = ALIGN(size, ARCH_DMA_MINALIGN);" is the right thing to do.

-- 
Damien Le Moal
Western Digital Research


  reply	other threads:[~2024-03-28  7:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-26 12:43 Yihang Li
2024-03-26 13:14 ` Damien Le Moal
2024-03-26 13:32   ` John Garry
2024-03-26 13:40     ` Damien Le Moal
2024-03-28  6:35     ` Christoph Hellwig
2024-03-28  6:59       ` Yihang Li
2024-03-28  7:23         ` Damien Le Moal
2024-03-28  7:29           ` Christoph Hellwig
2024-03-28  7:36             ` Damien Le Moal [this message]
2024-03-28  7:45               ` Christoph Hellwig
2024-03-28  8:00                 ` Yihang Li

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