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Date:   Fri, 20 May 2022 15:44:04 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>, gregkh@linuxfoundation.org,
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Subject: Re: [PATCH] char/mem: only use {read,write}_iter, not the old
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On Fri, May 20, 2022 at 09:32:34AM -0600, Jens Axboe wrote:

> Didn't look closer, but I'm assuming this is _mostly_ tied to needing to
> init 48 bytes of kiocb for each one. There might be ways to embed a
> sync_kiocb inside the kiocb for the bits we need there, at least that
> could get us down to 32 bytes.

My bet would be on iocb_flags() (and kiocb_set_rw_flags()) tests and
pointer-chasing, actually.  I'd been sick on and off since early November,
trying to dig myself from under the piles right now.  Christoph's
patches in that area are somewhere in the pile ;-/