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Date:   Mon, 20 Aug 2018 10:38:16 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Li RongQing <lirongqing@baidu.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dan Williams <dan.j.williams@intel.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Souptick Joarder <jrdr.linux@gmail.com>,
        darrick.wong@oracle.com
Subject: Re: [PATCH] mm: introduce kvvirt_to_page() helper
Message-ID: <20180820173816.GE25153@bombadil.infradead.org>
References: <1534596541-31393-1-git-send-email-lirongqing@baidu.com>
 <20180820144116.GO29735@dhcp22.suse.cz>
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On Mon, Aug 20, 2018 at 04:41:16PM +0200, Michal Hocko wrote:
> > +++ b/fs/xfs/xfs_buf.c
> >  	for (i = 0; i < bp->b_page_count; i++) {
> > -		bp->b_pages[i] = mem_to_page((void *)pageaddr);
> > +		bp->b_pages[i] = kvvirt_to_page((void *)pageaddr);
> >  		pageaddr += PAGE_SIZE;

This wants mem_range_to_page_array().

> > +++ b/net/9p/trans_virtio.c
> >  		for (index = 0; index < nr_pages; index++) {
> > -			if (is_vmalloc_addr(p))
> > -				(*pages)[index] = vmalloc_to_page(p);
> > -			else
> > -				(*pages)[index] = kmap_to_page(p);
> > +			(*pages)[index] = kvvirt_to_page(p);

Also mem_range_to_page_array().

> > +++ b/net/ceph/crypto.c
> > @@ -191,11 +191,7 @@ static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg,
> >  		struct page *page;
> >  		unsigned int len = min(chunk_len - off, buf_len);
> >  
> > -		if (is_vmalloc)
> > -			page = vmalloc_to_page(buf);
> > -		else
> > -			page = virt_to_page(buf);
> > -
> > +		page = kvvirt_to_page(buf);
> >  		sg_set_page(sg, page, len, off);
> >  
> >  		off = 0;

This whole function wants to move into the core and be called something like
sg_alloc_table_from_virt().

> > +++ b/net/packet/af_packet.c
> > @@ -374,15 +367,15 @@ static void __packet_set_status(struct packet_sock *po, void *frame, int status)
> >  	switch (po->tp_version) {
> >  	case TPACKET_V1:
> >  		h.h1->tp_status = status;
> > -		flush_dcache_page(pgv_to_page(&h.h1->tp_status));
> > +		flush_dcache_page(kvvirt_to_page(&h.h1->tp_status));

This driver really wants flush_dcache_range(start, len).