From: Linus Torvalds <torvalds@linux-foundation.org>
To: David Howells <dhowells@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@lst.de>,
Christian Brauner <christian@brauner.io>,
David Laight <David.Laight@aculab.com>,
Matthew Wilcox <willy@infradead.org>,
Jeff Layton <jlayton@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-mm@kvack.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 09/13] iov_iter: Add a kernel-type iterator-only iteration function
Date: Fri, 22 Sep 2023 11:51:19 -0700 [thread overview]
Message-ID: <CAHk-=whyv0cs056T8TvY1f0nOf+Gsb6oRWetxt+LiFZUD4KQCw@mail.gmail.com> (raw)
In-Reply-To: <20230922120227.1173720-10-dhowells@redhat.com>
On Fri, 22 Sept 2023 at 05:03, David Howells <dhowells@redhat.com> wrote:
>
> Add an iteration function that can only iterate over kernel internal-type
> iterators (ie. BVEC, KVEC, XARRAY) and not user-backed iterators (ie. UBUF
> and IOVEC). This allows for smaller iterators to be built when it is known
> the caller won't have a user-backed iterator.
This one is pretty ugly, and has no actual users.
Without even explaining why we'd care about this abomination, NAK.
If we actyually have some static knowledge of "this will only use
iterators X/Y/Z", then we should probably pass that in as a constant
bitmask to the thing, instead of this kind of "kernel only" special
case.
But even then, we'd want to have actual explicit use-cases, not a
hypothetical "if you have this situation here's this function".
Linus
next prev parent reply other threads:[~2023-09-22 18:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 12:02 [PATCH v6 00/13] iov_iter: Convert the iterator macros into inline funcs David Howells
2023-09-22 12:02 ` [PATCH v6 01/13] iov_iter: Remove last_offset from iov_iter as it was for ITER_PIPE David Howells
2023-09-22 12:02 ` [PATCH v6 02/13] iov_iter: Be consistent about the __user tag on copy_mc_to_user() David Howells
2023-09-22 12:02 ` [PATCH v6 03/13] sound: Fix snd_pcm_readv()/writev() to use iov access functions David Howells
2023-09-22 12:02 ` [PATCH v6 04/13] infiniband: Use user_backed_iter() to see if iterator is UBUF/IOVEC David Howells
2023-09-22 12:02 ` [PATCH v6 05/13] iov_iter: Renumber ITER_* constants David Howells
2023-09-22 12:02 ` [PATCH v6 06/13] iov_iter: Derive user-backedness from the iterator type David Howells
2023-09-22 12:02 ` [PATCH v6 07/13] iov_iter: Convert iterate*() to inline funcs David Howells
2023-09-22 12:02 ` [PATCH v6 08/13] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() David Howells
2023-09-22 16:34 ` Linus Torvalds
2023-09-22 12:02 ` [PATCH v6 09/13] iov_iter: Add a kernel-type iterator-only iteration function David Howells
2023-09-22 18:51 ` Linus Torvalds [this message]
2023-09-22 12:02 ` [PATCH v6 10/13] iov_iter, net: Move csum_and_copy_to/from_iter() to net/ David Howells
2023-09-22 12:02 ` [PATCH v6 11/13] iov_iter, net: Fold in csum_and_memcpy() David Howells
2023-09-22 12:02 ` [PATCH v6 12/13] iov_iter, net: Merge csum_and_copy_from_iter{,_full}() together David Howells
2023-09-22 12:02 ` [PATCH v6 13/13] iov_iter, net: Move hash_and_copy_to_iter() to net/ David Howells
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