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Message-ID: <d2ccef1e-2bea-4596-8787-8d2491ce0278@acm.org>
Date:   Fri, 3 Nov 2023 08:04:15 -0700
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Subject: Re: [PATCH RFC V2 6/6] RDMA/rxe: Support PAGE_SIZE aligned MR
Content-Language: en-US
To:     Li Zhijian <lizhijian@fujitsu.com>, zyjzyj2000@gmail.com,
        jgg@ziepe.ca, leon@kernel.org, linux-rdma@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, rpearsonhpe@gmail.com,
        matsuda-daisuke@fujitsu.com, yi.zhang@redhat.com
References: <20231103095549.490744-1-lizhijian@fujitsu.com>
 <20231103095549.490744-7-lizhijian@fujitsu.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <20231103095549.490744-7-lizhijian@fujitsu.com>
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On 11/3/23 02:55, Li Zhijian wrote:
> -	return ib_sg_to_pages(ibmr, sgl, sg_nents, sg_offset, rxe_set_page);
> +	for_each_sg(sgl, sg, sg_nents, i) {
> +		u64 dma_addr = sg_dma_address(sg) + sg_offset;
> +		unsigned int dma_len = sg_dma_len(sg) - sg_offset;
> +		u64 end_dma_addr = dma_addr + dma_len;
> +		u64 page_addr = dma_addr & PAGE_MASK;
> +
> +		if (sg_dma_len(sg) == 0) {
> +			rxe_dbg_mr(mr, "empty SGE\n");
> +			return -EINVAL;
> +		}
> +		do {
> +			int ret = rxe_store_page(mr, page_addr);
> +			if (ret)
> +				return ret;
> +
> +			page_addr += PAGE_SIZE;
> +		} while (page_addr < end_dma_addr);
> +		sg_offset = 0;
> +	}
> +
> +	return ib_sg_to_pages(ibmr, sgl, sg_nents, sg_offset_p, rxe_set_page);
>   }

Is this change necessary? There is already a loop in ib_sg_to_pages()
that splits SG entries that are larger than mr->page_size into entries
with size mr->page_size.

Bart.