From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, David Laight <David.Laight@aculab.com>,
Al Viro <viro@zeniv.linux.org.uk>, Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@list.de>,
Christian Brauner <christian@brauner.io>,
Matthew Wilcox <willy@infradead.org>,
Jeff Layton <jlayton@kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc()
Date: Wed, 16 Aug 2023 21:35:14 +0100 [thread overview]
Message-ID: <665724.1692218114@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAHk-=wjFrVp6srTBsMKV8LBjCEO0bRDYXm-KYrq7oRk0TGr6HA@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > What about ITER_BVEC_MC ??
>
> That probably would be the best option. Just make it a proper
> ITER_xyz, instead of an odd sub-case for one ITER (but set up in such
> a way that it looks like it might happen for other ITER_xyz cases).
I'm not sure that buys us anything. It would then require every call to
iov_iter_is_bvec()[*] to check for two values instead of one - including in
iterate_and_advance() - and *still* we'd have to have the special-casing in
_copy_from_iter() and copy_page_from_iter_atomic().
The issue is that ITER_xyz changes the iteration function - but we don't
actually want to do that; rather, we need to change the step function.
David
[*] There's a bunch of them outside of iov_iter.c.
next prev parent reply other threads:[~2023-08-16 20:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-16 12:07 [PATCH v3 0/2] iov_iter: Convert the iterator macros into inline funcs David Howells
2023-08-16 12:07 ` [PATCH v3 1/2] iov_iter: Convert iterate*() to " David Howells
2023-08-16 12:07 ` [PATCH v3 2/2] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() David Howells
2023-08-16 12:28 ` David Laight
2023-08-16 13:00 ` David Howells
2023-08-16 14:19 ` David Laight
2023-08-16 18:50 ` Linus Torvalds
2023-08-16 20:35 ` David Howells [this message]
2023-08-17 4:18 ` Linus Torvalds
2023-08-17 8:41 ` David Laight
2023-08-17 14:38 ` Linus Torvalds
2023-08-17 15:16 ` David Laight
2023-08-17 15:31 ` Linus Torvalds
2023-08-17 16:06 ` David Laight
2023-08-18 15:19 ` David Howells
2023-08-18 15:42 ` David Laight
2023-08-18 16:48 ` David Howells
2023-08-18 21:39 ` David Laight
2023-08-18 11:42 ` David Howells
2023-08-18 12:16 ` David Laight
2023-08-18 12:26 ` Matthew Wilcox
2023-08-18 12:41 ` David Laight
2023-08-18 13:33 ` David Howells
2023-08-18 11:39 ` David Howells
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