linux-kernel - [PATCH v3 08/11] swiotlb-xen: remove XEN_PFN

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Date:   Fri, 10 Jul 2020 15:34:24 -0700
From:   Stefano Stabellini <sstabellini@...nel.org>
To:     jgross@...e.com, boris.ostrovsky@...cle.com, konrad.wilk@...cle.com
Cc:     sstabellini@...nel.org, xen-devel@...ts.xenproject.org,
        linux-kernel@...r.kernel.org, hch@...radead.org,
        Stefano Stabellini <stefano.stabellini@...inx.com>
Subject: [PATCH v3 08/11] swiotlb-xen: remove XEN_PFN_PHYS

From: Stefano Stabellini <stefano.stabellini@...inx.com>

XEN_PFN_PHYS is only used in one place in swiotlb-xen making things more
complex than need to be.

Remove the definition of XEN_PFN_PHYS and open code the cast in the one
place where it is needed.

Signed-off-by: Stefano Stabellini <stefano.stabellini@...inx.com>
---
 drivers/xen/swiotlb-xen.c | 7 +------
 include/xen/page.h        | 1 -
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index e2c35f45f91e..03d118b6c141 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -52,11 +52,6 @@ static unsigned long xen_io_tlb_nslabs;
  * Quick lookup value of the bus address of the IOTLB.
  */
 
-/*
- * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t
- * can be 32bit when dma_addr_t is 64bit leading to a loss in
- * information if the shift is done before casting to 64bit.
- */
 static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
 {
 	unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
@@ -101,7 +96,7 @@ static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
 {
 	unsigned long bfn = XEN_PFN_DOWN(dma_addr);
 	unsigned long xen_pfn = bfn_to_local_pfn(bfn);
-	phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn);
+	phys_addr_t paddr = (phys_addr_t)xen_pfn << XEN_PAGE_SHIFT;
 
 	/* If the address is outside our domain, it CAN
 	 * have the same virtual address as another address
diff --git a/include/xen/page.h b/include/xen/page.h
index df6d6b6ec66e..285677b42943 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -24,7 +24,6 @@
 
 #define XEN_PFN_DOWN(x)	((x) >> XEN_PAGE_SHIFT)
 #define XEN_PFN_UP(x)	(((x) + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT)
-#define XEN_PFN_PHYS(x)	((phys_addr_t)(x) << XEN_PAGE_SHIFT)
 
 #include <asm/xen/page.h>
 
-- 
2.17.1