From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Jens Axboe <axboe@fb.com>,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [RFC] weird semantics of SG_DXFER_TO_FROM_DEV in BLK_DEV_SKD (drivers/block/skd*)
Date: Sun, 3 Apr 2016 23:52:20 -0700 [thread overview]
Message-ID: <20160404065220.GA9447@infradead.org> (raw)
In-Reply-To: <20160404033845.GE17997@ZenIV.linux.org.uk>
On Mon, Apr 04, 2016 at 04:38:45AM +0100, Al Viro wrote:
> I've no idea if anything is still using SG_DXFER_TO_FROM_DEV, but this
> behaviour AFAICS doesn't match that of write() on /dev/sg* (both
> in and out are done) or normal SG_IO (either both in and out, in case if it
> hits bio_map_user_iov(), or only out if it hits bio_copy_user_iov()). In
> all cases the out part is done. Here it is skipped.
>
> Not sure who (if anybody) maintains it these days, but that behaviour looks
> wrong...
The right fix is to kill the duplicate SG_IO implementation and use
the block layer one. The driver actually is a pretty straight SCSI
implementation, so making it a block driver has been a mistake from the
start. I'll see if I can maybe get hold of hardware for the driver - it
seems pretty much unmaintained unfortunately.
next prev parent reply other threads:[~2016-04-04 6:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 3:38 [RFC] weird semantics of SG_DXFER_TO_FROM_DEV in BLK_DEV_SKD (drivers/block/skd*) Al Viro
2016-04-04 6:52 ` Christoph Hellwig [this message]
2016-04-04 17:16 ` Al Viro
2016-04-04 18:47 ` Al Viro
2016-04-04 19:50 ` Al Viro
2016-04-04 23:45 ` Al Viro
2016-04-07 15:55 ` Christoph Hellwig
2016-04-08 19:19 ` Al Viro
2016-04-07 15:53 ` 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=20160404065220.GA9447@infradead.org \
--to=hch@infradead.org \
--cc=axboe@fb.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@ZenIV.linux.org.uk \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.