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
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