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[Xen-devel] [PATCH][Linux] gnttab: make dma address conversion logic of

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] [PATCH][Linux] gnttab: make dma address conversion logic of gnttab dma arch specific.
From: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Date: Mon, 11 Jun 2007 16:35:27 +0900
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Mon, 11 Jun 2007 00:33:51 -0700
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This patch is cleaned up of the patch which was sent as
http://lists.xensource.com/archives/html/xen-devel/2007-06/msg00324.html

# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Date 1181545986 -32400
# Node ID 69e2dd4e06c405a92717c5f1818f5096e1dc0bcd
# Parent  d5e0eb7dd069c0ffc1854da81aa143ccfb0ad66e
make dma address conversion logic of gnttab dma arch specific.
gnttab_dma_map_page() and gnttab_dma_unmap_page() uses machine address
with dma address interchangebly.
However it doesn't work with auto translated mode enabled (i.e. on ia64)
because

- bus address space(dma_addr_t) is different from machine address
  space(maddr_t).
  With the terminology in xen/include/public/mm.h,
  dma_addr_t is maddr and maddr_t is gmaddr.
  So they should be handled differently with auto translated physmap mode
  enabled.

- dma address conversion depends on dma api implementation and
  its paravirtualization.
  "pfn_valid(mfn_to_local_pfn(maddr >> PAGE_SHIFT)" check in
  gnttab_dma_map_page() doesn't make sense with auto translate physmap
  mode enabled.

To address those issues, split those logic from gnttab_dma_map_page() and
gnttab_dma_unmap_page(), and put it into arch specific files.
This patch doesn't change the already existing x86 logic.

PATCHNAME: make_dma_address_conversion_logic_of_gnttab_dma_arch_specific

diff -r d5e0eb7dd069 -r 69e2dd4e06c4 arch/i386/kernel/pci-dma-xen.c
--- a/arch/i386/kernel/pci-dma-xen.c    Sun Jun 10 19:50:32 2007 +0100
+++ b/arch/i386/kernel/pci-dma-xen.c    Mon Jun 11 16:13:06 2007 +0900
@@ -19,6 +19,7 @@
 #include <asm/swiotlb.h>
 #include <asm/tlbflush.h>
 #include <asm-i386/mach-xen/asm/swiotlb.h>
+#include <asm-i386/mach-xen/asm/gnttab_dma.h>
 #include <asm/bug.h>
 
 #ifdef __x86_64__
@@ -58,6 +59,12 @@ static int __init pci_iommu_init(void)
 /* Must execute after PCI subsystem */
 fs_initcall(pci_iommu_init);
 #endif
+
+/* this should be in somewhere appropriate */
+int gnttab_dma_local_pfn(struct page *page)
+{
+       return pfn_valid(mfn_to_local_pfn(pfn_to_mfn(page_to_pfn(page))));
+}
 
 struct dma_coherent_mem {
        void            *virt_base;
diff -r d5e0eb7dd069 -r 69e2dd4e06c4 arch/i386/kernel/swiotlb.c
--- a/arch/i386/kernel/swiotlb.c        Sun Jun 10 19:50:32 2007 +0100
+++ b/arch/i386/kernel/swiotlb.c        Mon Jun 11 16:13:06 2007 +0900
@@ -27,6 +27,7 @@
 #include <asm/uaccess.h>
 #include <xen/gnttab.h>
 #include <xen/interface/memory.h>
+#include <asm-i386/mach-xen/asm/gnttab_dma.h>
 
 int swiotlb;
 EXPORT_SYMBOL(swiotlb);
diff -r d5e0eb7dd069 -r 69e2dd4e06c4 drivers/xen/core/gnttab.c
--- a/drivers/xen/core/gnttab.c Sun Jun 10 19:50:32 2007 +0100
+++ b/drivers/xen/core/gnttab.c Mon Jun 11 16:13:06 2007 +0900
@@ -593,20 +593,18 @@ EXPORT_SYMBOL(gnttab_copy_grant_page);
  *
  * All other pages are simply returned as is.
  */
-maddr_t gnttab_dma_map_page(struct page *page)
-{
-       maddr_t maddr = page_to_bus(page);
+void __gnttab_dma_map_page(struct page *page,
+                          int (*local_pfn)(struct page *page))
+{
        unsigned int seq;
 
-       if (!PageForeign(page))
-               return maddr;
+       if (!is_running_on_xen() || !PageForeign(page))
+               return;
 
        do {
                seq = read_seqbegin(&gnttab_dma_lock);
-               maddr = page_to_bus(page);
-
-               /* Has it become a local MFN? */
-               if (pfn_valid(mfn_to_local_pfn(maddr >> PAGE_SHIFT)))
+
+               if (local_pfn && (*local_pfn)(page))
                        break;
 
                atomic_set(&page->_mapcount, 0);
@@ -614,8 +612,6 @@ maddr_t gnttab_dma_map_page(struct page 
                /* Make _mapcount visible before read_seqretry. */
                smp_mb();
        } while (unlikely(read_seqretry(&gnttab_dma_lock, seq)));
-
-       return maddr;
 }
 
 int gnttab_resume(void)
diff -r d5e0eb7dd069 -r 69e2dd4e06c4 include/asm-i386/mach-xen/asm/gnttab_dma.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-xen/asm/gnttab_dma.h        Mon Jun 11 16:13:06 
2007 +0900
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2007 Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
+ * Copyright (c) 2007 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _ASM_I386_GNTTAB_DMA_H
+#define _ASM_I386_GNTTAB_DMA_H
+
+int gnttab_dma_local_pfn(struct page *page);
+
+static inline maddr_t gnttab_dma_map_page(struct page *page)
+{
+       __gnttab_dma_map_page(page, &gnttab_dma_local_pfn);
+       return page_to_bus(page);
+}
+
+static inline void gnttab_dma_unmap_page(maddr_t maddr)
+{
+       __gnttab_dma_unmap_page(virt_to_page(bus_to_virt(maddr)));
+}
+
+#endif /* _ASM_I386_GNTTAB_DMA_H */
diff -r d5e0eb7dd069 -r 69e2dd4e06c4 include/asm-ia64/gnttab_dma.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-ia64/gnttab_dma.h     Mon Jun 11 16:13:06 2007 +0900
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2007 Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
+ * Copyright (c) 2007 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _ASM_IA64_GNTTAB_DMA_H
+#define _ASM_IA64_GNTTAB_DMA_H
+
+/* caller must get dma address after calling this function */
+static inline void gnttab_dma_use_page(struct page *page)
+{
+       __gnttab_dma_map_page(page, NULL);
+}
+
+static inline dma_addr_t gnttab_dma_map_page(struct page *page)
+{
+       gnttab_dma_use_page(page);
+       return page_to_bus(page);
+}
+
+static inline dma_addr_t gnttab_dma_map_virt(void *ptr)
+{
+       return gnttab_dma_map_page(virt_to_page(ptr)) + offset_in_page(ptr);
+}
+
+static inline void gnttab_dma_unmap_page(dma_addr_t dma_address)
+{
+       __gnttab_dma_unmap_page(virt_to_page(bus_to_virt(dma_address)));
+}
+
+#endif /* _ASM_IA64_GNTTAB_DMA_H */
diff -r d5e0eb7dd069 -r 69e2dd4e06c4 include/xen/gnttab.h
--- a/include/xen/gnttab.h      Sun Jun 10 19:50:32 2007 +0100
+++ b/include/xen/gnttab.h      Mon Jun 11 16:13:06 2007 +0900
@@ -103,9 +103,9 @@ void gnttab_grant_foreign_transfer_ref(g
                                       unsigned long pfn);
 
 int gnttab_copy_grant_page(grant_ref_t ref, struct page **pagep);
-maddr_t gnttab_dma_map_page(struct page *page);
-
-static inline void gnttab_dma_unmap_page(maddr_t mfn)
+void __gnttab_dma_map_page(struct page *page,
+                          int (*local_pfn)(struct page *page));
+static inline void __gnttab_dma_unmap_page(struct page *page)
 {
 }
 


-- 
yamahata

Attachment: 41_69e2dd4e06c4_make_dma_address_conversion_logic_of_gnttab_dma_arch_specific.patch
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