Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <68463af5-952b-a024-21fd-fa9e5fc37eb3@linux.alibaba.com>
Date:   Wed, 16 Nov 2022 20:17:53 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.4.0
Subject: Re: [PATCH v3 1/2] fscache,cachefiles: add prepare_ondemand_read()
 callback
Content-Language: en-US
To:     Jeff Layton <jlayton@kernel.org>, xiang@kernel.org,
        chao@kernel.org, linux-erofs@lists.ozlabs.org,
        linux-cachefs@redhat.com, dhowells@redhat.com
Cc:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
References: <20221116104502.107431-1-jefflexu@linux.alibaba.com>
 <20221116104502.107431-2-jefflexu@linux.alibaba.com>
 <2b595b62f6ecd28298a860fcdc5b4941dcafd9eb.camel@kernel.org>
From:   Jingbo Xu <jefflexu@linux.alibaba.com>
In-Reply-To: <2b595b62f6ecd28298a860fcdc5b4941dcafd9eb.camel@kernel.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi Jeff,

Thanks for the comment!

On 11/16/22 7:58 PM, Jeff Layton wrote:

>>  
>> -/*
>> - * Prepare a read operation, shortening it to a cached/uncached
>> - * boundary as appropriate.
>> - */
>> -static enum netfs_io_source cachefiles_prepare_read(struct netfs_io_subrequest *subreq,
>> -						      loff_t i_size)
>> +static enum netfs_io_source cachefiles_do_prepare_read(struct netfs_cache_resources *cres,
>> +					loff_t *_start, size_t *_len,
>> +					unsigned long *_flags, loff_t i_size)
> 
> _start is never changed, so it should be passed by value instead of by
> pointer. 

Yeah, start is indeed unchanged, and I think it's also reasonable to
pass it by value rather than by pointer.


> I'd also reverse the position of the arguments for _flags and
> i_size.  Otherwise, the CPU/compiler have to shuffle things around more
> in cachefiles_prepare_ondemand_read before they call this.

Yeah I didn't notice the details.


I will fix the above two issues in a quick v4 version.

Many thanks for the feedback.


-- 
Thanks,
Jingbo