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Date:   Fri, 20 May 2022 08:36:17 -0600
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Subject: Re: [PATCH v4 1/3] random: convert to using fops->read_iter()
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To:     "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Theodore Ts'o <tytso@mit.edu>, Christoph Hellwig <hch@lst.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>
References: <20220520094459.116240-1-Jason@zx2c4.com>
 <20220520094459.116240-2-Jason@zx2c4.com> <YoeZi94CpGW9LE/y@zx2c4.com>
From:   Jens Axboe <axboe@kernel.dk>
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On 5/20/22 7:37 AM, Jason A. Donenfeld wrote:
> On Fri, May 20, 2022 at 11:44:57AM +0200, Jason A. Donenfeld wrote:
>>  const struct file_operations urandom_fops = {
>> -	.read = urandom_read,
>> +	.read_iter = urandom_read_iter,
> 
> One thing I noticed is that drivers/char/mem.c has both the .read and
> the .read_iter functions for /dev/zero and /dev/null and such. I wonder
> if the .read ones can be removed?

I'm not sure if we have a clear "always use this if available" set of
rules for this. Ideally we'd want it to be:

1) Use ->read_iter() if available
2) If not, use ->read()

Might require a bit of auditing to ensure that's the case, and if we
can say that it is, then we could clean that up too.

-- 
Jens Axboe