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Date:   Mon, 22 Jul 2019 12:07:22 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     John Hubbard <jhubbard@nvidia.com>
Cc:     Christoph Hellwig <hch@lst.de>, john.hubbard@gmail.com,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= <bjorn.topel@intel.com>,
        Boaz Harrosh <boaz@plexistor.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Chinner <david@fromorbit.com>,
        David Airlie <airlied@linux.ie>,
        "David S . Miller" <davem@davemloft.net>,
        Ilya Dryomov <idryomov@gmail.com>, Jan Kara <jack@suse.cz>,
        Jason Gunthorpe <jgg@ziepe.ca>, Jens Axboe <axboe@kernel.dk>,
        =?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Magnus Karlsson <magnus.karlsson@intel.com>,
        Miklos Szeredi <miklos@szeredi.hu>,
        Ming Lei <ming.lei@redhat.com>, Sage Weil <sage@redhat.com>,
        Santosh Shilimkar <santosh.shilimkar@oracle.com>,
        Yan Zheng <zyan@redhat.com>, netdev@vger.kernel.org,
        dri-devel@lists.freedesktop.org, linux-mm@kvack.org,
        linux-rdma@vger.kernel.org, bpf@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] drivers/gpu/drm/via: convert put_page() to
 put_user_page*()
Message-ID: <20190722190722.GF363@bombadil.infradead.org>
References: <20190722043012.22945-1-jhubbard@nvidia.com>
 <20190722043012.22945-2-jhubbard@nvidia.com>
 <20190722093355.GB29538@lst.de>
 <397ff3e4-e857-037a-1aee-ff6242e024b2@nvidia.com>
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On Mon, Jul 22, 2019 at 11:53:54AM -0700, John Hubbard wrote:
> On 7/22/19 2:33 AM, Christoph Hellwig wrote:
> > On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubbard@gmail.com wrote:
> >>  		for (i = 0; i < vsg->num_pages; ++i) {
> >>  			if (NULL != (page = vsg->pages[i])) {
> >>  				if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction))
> >> -					SetPageDirty(page);
> >> -				put_page(page);
> >> +					put_user_pages_dirty(&page, 1);
> >> +				else
> >> +					put_user_page(page);
> >>  			}
> > 
> > Can't just pass a dirty argument to put_user_pages?  Also do we really
> 
> Yes, and in fact that would help a lot more than the single page case,
> which is really just cosmetic after all.
> 
> > need a separate put_user_page for the single page case?
> > put_user_pages_dirty?
> 
> Not really. I'm still zeroing in on the ideal API for all these call sites,
> and I agree that the approach below is cleaner.

so enum { CLEAN = 0, DIRTY = 1, LOCK = 2, DIRTY_LOCK = 3 };
?