Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Message-ID: <b1e7991f-b01e-b29c-954a-0d55e971840e@kernel.dk>
Date:   Fri, 20 May 2022 08:38:35 -0600
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101
 Thunderbird/91.8.1
Subject: Re: [PATCH] char/mem: only use {read,write}_iter, not the old
 {read,write} functions
Content-Language: en-US
To:     "Jason A. Donenfeld" <Jason@zx2c4.com>, gregkh@linuxfoundation.org,
        linux-kernel@vger.kernel.org
Cc:     Al Viro <viro@zeniv.linux.org.uk>
References: <20220520135030.166831-1-Jason@zx2c4.com>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <20220520135030.166831-1-Jason@zx2c4.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 5/20/22 7:50 AM, Jason A. Donenfeld wrote:
> Currently mem.c implements both the {read,write}_iter functions and the
> {read,write} functions. But with {read,write} going away at some point
> in the future, and most kernel code made to prefer {read,write}_iter,
> there's no point in keeping around the old code. Actually, this comment
> in __kernel_read() indicates that having both might be plain wrong:
> 
>         /*
>          * Also fail if ->read_iter and ->read are both wired up as that
>          * implies very convoluted semantics.
>          */
>         if (unlikely(!file->f_op->read_iter || file->f_op->read))
>                 return warn_unsupported(file, "read");

Nice, just another bit of wasted space due to not having clearly
defined iter vs non-iter.

Reviewed-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe