linux-kernel - [RFC PATCH v2 06/12] drivers/xen/swiotlb-xen: update usage of address zone modifiers

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Date:   Mon, 21 May 2018 17:58:29 +0000
From:   Huaisheng HS1 Ye <yehs1@...ovo.com>
To:     "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "willy@...radead.org" <willy@...radead.org>
CC:     "mhocko@...e.com" <mhocko@...e.com>,
        "vbabka@...e.cz" <vbabka@...e.cz>,
        "mgorman@...hsingularity.net" <mgorman@...hsingularity.net>,
        "kstewart@...uxfoundation.org" <kstewart@...uxfoundation.org>,
        "alexander.levin@...izon.com" <alexander.levin@...izon.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "colyli@...e.de" <colyli@...e.de>,
        NingTing Cheng <chengnt@...ovo.com>,
        Ocean HY1 He <hehy1@...ovo.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
        "linux-btrfs@...r.kernel.org" <linux-btrfs@...r.kernel.org>,
        "hch@....de" <hch@....de>,
        "konrad.wilk@...cle.com" <konrad.wilk@...cle.com>,
        "konrad.wilk@...cle.com" <konrad.wilk@...cle.com>,
        "boris.ostrovsky@...cle.com" <boris.ostrovsky@...cle.com>,
        "jgross@...e.com" <jgross@...e.com>
Subject: [RFC PATCH v2 06/12] drivers/xen/swiotlb-xen: update usage of address
 zone modifiers

Use __GFP_ZONE_MASK to replace (__GFP_DMA | __GFP_HIGHMEM).

In function xen_swiotlb_alloc_coherent, it is obvious that __GFP_DMA32
is not the expecting zone type.

___GFP_DMA, ___GFP_HIGHMEM and ___GFP_DMA32 have been deleted from GFP 
bitmasks, the bottom three bits of GFP mask is reserved for storing
encoded zone number.
__GFP_DMA, __GFP_HIGHMEM and __GFP_DMA32 should not be operated with
each others by OR. 

Signed-off-by: Huaisheng Ye <yehs1@...ovo.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Juergen Gross <jgross@...e.com>
---
 drivers/xen/swiotlb-xen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 5bb72d3..00e8368 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -315,7 +315,7 @@ int __ref xen_swiotlb_init(int verbose, bool early)
        * machine physical layout.  We can't allocate highmem
        * because we can't return a pointer to it. 
        */
-       flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
+       flags &= ~__GFP_ZONE_MASK;
 
        /* On ARM this function returns an ioremap'ped virtual address for 
         * which virt_to_phys doesn't return the corresponding physical
-- 
1.8.3.1