From: Al Viro <viro@ZenIV.linux.org.uk>
To: David Howells <dhowells@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/10] iov_iter: Add new iters and use with AFS
Date: Thu, 13 Sep 2018 18:58:45 +0100 [thread overview]
Message-ID: <20180913175845.GS19965@ZenIV.linux.org.uk> (raw)
In-Reply-To: <153685389564.14766.11306559824641824935.stgit@warthog.procyon.org.uk>
On Thu, Sep 13, 2018 at 04:51:35PM +0100, David Howells wrote:
>
> Hi Al,
>
> Here's a set of patches that adds two new iov_iter types and then makes AFS
> use them to do I/O. The iov_iter changes are:
>
> (1) Separate the type from the direction in the iov_iter struct and
> provide accessor functions to wrap type checking.
>
> (2) Renumber the type constants to be contiguous small unsigned integers,
> starting from 0 and then use switch-statements rather than if-else
> chains using bit-testing.
>
> Note that the compiler can optimise this better by using CMP rather
> than AND/TEST, say, as comparing integers requires fewer CMP
> instructions or can use jump tables.
>
> (3) Change iov_offset from size_t to loff_t. This allows iov_offset to be
> then used as a byte offset with ITER_MAPPING and allows 4GiB and larger
> reads and writes to be proposed.
>
> This makes no difference on a 64-bit system, but does make a 32-bit
> compilation a bit larger.
>
> (4) Add an ITER_MAPPING iterator type. This provides an iterator that
> directly accesses an address_space, and assumes that the target pages
> are in some way locked (eg. PG_lock or PG_writeback).
>
> (5) Add an ITER_DISCARD iterator type. This provides an iterator that
> simply discards anything written to it. It cannot be used as a data
> source.
Hmm... I'll take a look in about an hour (need to finish the sodding tty-ioctl
stuff first), will post review then. Sorry, I remember seeing it posted several
weeks ago, slipped through the cracks then ;-/
next prev parent reply other threads:[~2018-09-13 23:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-13 15:51 [PATCH 00/10] iov_iter: Add new iters and use with AFS David Howells
2018-09-13 15:51 ` [PATCH 01/10] iov_iter: Separate type from direction and use accessor functions David Howells
2018-09-13 15:51 ` [PATCH 02/10] iov_iter: Renumber the ITER_* constants in uio.h David Howells
2018-09-13 15:52 ` [PATCH 03/10] iov_iter: Make count and iov_offset loff_t not size_t David Howells
2018-09-13 15:52 ` [PATCH 04/10] iov_iter: Add mapping and discard iterator types David Howells
2018-09-14 4:18 ` Al Viro
2018-09-14 12:57 ` Trond Myklebust
2018-09-17 21:32 ` David Howells
2018-09-17 20:58 ` David Howells
2018-09-13 15:52 ` [PATCH 05/10] afs: Better tracing of protocol errors David Howells
2018-09-13 15:52 ` [PATCH 06/10] afs: Set up the iov_iter before calling afs_extract_data() David Howells
2018-09-13 15:52 ` [PATCH 07/10] afs: Use ITER_MAPPING for writing David Howells
2018-09-13 15:52 ` [PATCH 08/10] afs: Add O_DIRECT read support David Howells
2018-09-13 15:52 ` [PATCH 09/10] afs: Add a couple of tracepoints to log I/O errors David Howells
2018-09-13 15:52 ` [PATCH 10/10] afs: Don't invoke the server to read data beyond EOF David Howells
2018-09-13 16:10 ` [PATCH 00/10] iov_iter: Add new iters and use with AFS Matthew Wilcox
2018-09-13 16:18 ` David Howells
2018-09-13 16:43 ` Matthew Wilcox
2018-09-13 17:05 ` David Howells
2018-09-13 17:58 ` Al Viro [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-08-06 13:16 David Howells
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180913175845.GS19965@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=dhowells@redhat.com \
--cc=linux-afs@lists.infradead.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).