From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>, 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: Thu, 7 Apr 2016 08:55:33 -0700 [thread overview]
Message-ID: <20160407155533.GB8703@infradead.org> (raw)
In-Reply-To: <20160404234508.GJ17997@ZenIV.linux.org.uk>
On Tue, Apr 05, 2016 at 12:45:08AM +0100, Al Viro wrote:
> AFAICS, what we need there is simply
> nr_pages = iov_iter_npages(iter);
> alignment = iov_iter_alignment(iter);
> if (alignment & (queue_dma_alignment(q) | q->dma_pad_mask))
> copy = true;
> and I really wonder if we care about special-casing the situation when the
> ends are not aligned to queue_virt_boundary(q). If we don't, we might as
> well add queue_virt_boundary(q) to the mask we are checking. If we do,
> it's not hard to add a variant that would calculate both the alignment and
> alignment for internal boundaries...
I suspect this is the right thing to do. Care to send a patch to Jens?
next prev parent reply other threads:[~2016-04-07 15:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 3:38 Al Viro
2016-04-04 6:52 ` Christoph Hellwig
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 [this message]
2016-04-08 19:19 ` Al Viro
2016-04-07 15:53 ` Christoph Hellwig
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