From: Al Viro <viro@zeniv.linux.org.uk>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Bart Van Assche <bart.vanassche@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
David Howells <dhowells@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@kernel.org>,
Logan Gunthorpe <logang@deltatee.com>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org,
Douglas Gilbert <dgilbert@interlog.com>
Subject: Re: [PATCH v5 3/9] iov_iter: Use IOCB/IOMAP_WRITE if available rather than iterator direction
Date: Sat, 14 Jan 2023 01:58:31 +0000 [thread overview]
Message-ID: <Y8IMR8BK3bLnr9ps@ZenIV> (raw)
In-Reply-To: <yq1ilh9ucg3.fsf@ca-mkp.ca.oracle.com>
On Fri, Jan 13, 2023 at 08:34:50PM -0500, Martin K. Petersen wrote:
>
> Bart,
>
> > I'm not sure that we still need the double copy in the sg driver. It
> > seems obscure to me that there is user space software that relies on
> > finding "0xec" in bytes not originating from a SCSI
> > device. Additionally, SCSI drivers that do not support residuals
> > should be something from the past.
>
> Yeah. I'm not aware of anything that relies on this still. But obviously
> Doug has more experience in the app dependency department.
Are we guaranteed to know the accurate amount of data that got transferred
for all surviving drivers? If we do, we can do accurate copy-out and all
apps will keep seeing what they currently do. If we don't, the best we
can do is replacing copy-in + IO + copy-out with memset + IO + copy-out.
next prev parent reply other threads:[~2023-01-14 1:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-11 14:27 [PATCH v5 0/9] iov_iter: Add extraction helpers David Howells
2023-01-11 14:27 ` [PATCH v5 1/9] iov_iter: Change the direction macros into an enum David Howells
2023-01-11 14:27 ` [PATCH v5 2/9] iov_iter: Use the direction in the iterator functions David Howells
2023-01-11 14:27 ` [PATCH v5 3/9] iov_iter: Use IOCB/IOMAP_WRITE if available rather than iterator direction David Howells
2023-01-12 7:54 ` Christoph Hellwig
2023-01-12 10:31 ` David Howells
2023-01-12 14:08 ` Christoph Hellwig
2023-01-12 17:37 ` Al Viro
2023-01-12 21:49 ` Bart Van Assche
2023-01-13 5:32 ` Christoph Hellwig
2023-01-14 1:33 ` Martin K. Petersen
2023-01-14 1:34 ` Martin K. Petersen
2023-01-14 1:58 ` Al Viro [this message]
2023-01-13 5:30 ` Christoph Hellwig
2023-01-12 21:56 ` Al Viro
2023-01-13 5:33 ` Christoph Hellwig
2023-01-11 14:28 ` [PATCH v5 4/9] iov_iter: Add a function to extract a page list from an iterator David Howells
2023-01-12 7:55 ` Christoph Hellwig
2023-01-12 21:15 ` Al Viro
2023-01-12 21:36 ` Al Viro
2023-01-13 5:26 ` Christoph Hellwig
2023-01-11 14:28 ` [PATCH v5 5/9] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
2023-01-11 14:28 ` [PATCH v5 6/9] netfs: Add a function to extract an iterator into a scatterlist David Howells
2023-01-11 14:28 ` [PATCH v5 7/9] bio: Rename BIO_NO_PAGE_REF to BIO_PAGE_REFFED and invert the meaning David Howells
2023-01-12 7:32 ` Christoph Hellwig
2023-01-11 14:28 ` [PATCH v5 8/9] iov_iter, block: Make bio structs pin pages rather than ref'ing if appropriate David Howells
2023-01-12 7:44 ` Christoph Hellwig
2023-01-12 10:28 ` David Howells
2023-01-12 14:09 ` Christoph Hellwig
2023-01-12 14:17 ` Christoph Hellwig
2023-01-12 14:58 ` David Howells
2023-01-12 15:02 ` Christoph Hellwig
2023-01-11 14:28 ` [PATCH v5 9/9] bio: Fix bio_flagged() so that it can be combined David Howells
2023-01-12 7:33 ` Christoph Hellwig
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=Y8IMR8BK3bLnr9ps@ZenIV \
--to=viro@zeniv.linux.org.uk \
--cc=axboe@kernel.dk \
--cc=bart.vanassche@gmail.com \
--cc=dgilbert@interlog.com \
--cc=dhowells@redhat.com \
--cc=hch@infradead.org \
--cc=jack@suse.cz \
--cc=jlayton@kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=logang@deltatee.com \
--cc=martin.petersen@oracle.com \
--cc=willy@infradead.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).