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From: npiggin@suse.de
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [patch 16/18] mm: special mapping nopage
Date: Wed, 05 Dec 2007 18:16:03 +1100	[thread overview]
Message-ID: <20071205071628.484654000@nick.local0.net> (raw)
In-Reply-To: 20071205071547.701344000@nick.local0.net

[-- Attachment #1: special-mapping-nopage.patch --]
[-- Type: text/plain, Size: 2340 bytes --]

Convert special mapping install from nopage to fault. This requires a
small special case in the do_linear_fault calculation in order to handle
vmas without ->vm_file set.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/memory.c |   10 +++++++---
 mm/mmap.c   |   19 +++++++++----------
 2 files changed, 16 insertions(+), 13 deletions(-)

Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -2352,9 +2352,13 @@ static int do_linear_fault(struct mm_str
 		unsigned long address, pte_t *page_table, pmd_t *pmd,
 		int write_access, pte_t orig_pte)
 {
-	pgoff_t pgoff = (((address & PAGE_MASK)
-			- vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
-	unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
+	pgoff_t pgoff;
+	unsigned int flags;
+
+	pgoff = (((address) - vma->vm_start) >> PAGE_SHIFT);
+	if (likely(vma->vm_file))
+		pgoff += vma->vm_pgoff;
+	flags = (write_access ? FAULT_FLAG_WRITE : 0);
 
 	pte_unmap(page_table);
 	return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Index: linux-2.6/mm/mmap.c
===================================================================
--- linux-2.6.orig/mm/mmap.c
+++ linux-2.6/mm/mmap.c
@@ -2149,24 +2149,23 @@ int may_expand_vm(struct mm_struct *mm, 
 }
 
 
-static struct page *special_mapping_nopage(struct vm_area_struct *vma,
-					   unsigned long address, int *type)
+static int special_mapping_fault(struct vm_area_struct *vma,
+				struct vm_fault *vmf)
 {
+	pgoff_t pgoff = vmf->pgoff;
 	struct page **pages;
 
-	BUG_ON(address < vma->vm_start || address >= vma->vm_end);
-
-	address -= vma->vm_start;
-	for (pages = vma->vm_private_data; address > 0 && *pages; ++pages)
-		address -= PAGE_SIZE;
+	for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
+		pgoff--;
 
 	if (*pages) {
 		struct page *page = *pages;
 		get_page(page);
-		return page;
+		vmf->page = page;
+		return 0;
 	}
 
-	return NOPAGE_SIGBUS;
+	return VM_FAULT_SIGBUS;
 }
 
 /*
@@ -2178,7 +2177,7 @@ static void special_mapping_close(struct
 
 static struct vm_operations_struct special_mapping_vmops = {
 	.close = special_mapping_close,
-	.nopage	= special_mapping_nopage,
+	.fault = special_mapping_fault,
 };
 
 /*

-- 


  parent reply	other threads:[~2007-12-05  7:59 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-05  7:15 [patch 00/18] remove nopage npiggin
2007-12-05  7:15 ` [patch 01/18] ia64: ia32 nopage npiggin
2007-12-05  7:15 ` [patch 02/18] relay: nopage npiggin
2007-12-05  7:15 ` [patch 03/18] drm: nopage npiggin
2007-12-05  9:05   ` Dave Airlie
2007-12-05  9:17     ` Nick Piggin
2007-12-05  7:15 ` [patch 04/18] uio: nopage npiggin
2007-12-05 10:04   ` Hans-Jürgen Koch
2007-12-05 10:10     ` Nick Piggin
2007-12-05 10:25       ` Hans-Jürgen Koch
2007-12-05 10:37         ` Nick Piggin
2007-12-05  7:15 ` [patch 05/18] kvm: nopage npiggin
2007-12-05 10:40   ` Avi Kivity
2007-12-05  7:15 ` [patch 06/18] ieee1394: nopage npiggin
2007-12-05 13:09   ` Stefan Richter
2007-12-05 13:15     ` Stefan Richter
2007-12-05 23:52       ` Nick Piggin
2007-12-05 23:51     ` Nick Piggin
2007-12-15 13:04       ` Stefan Richter
2007-12-15 13:01   ` Stefan Richter
2007-12-05  7:15 ` [patch 07/18] v4l: nopage npiggin
2007-12-08  0:31   ` Andrew Morton
2007-12-08  9:15     ` Ingo Molnar
2007-12-08 10:15       ` Andrew Morton
2007-12-09 17:10     ` Randy Dunlap
2007-12-10  5:06     ` [patch] x64/page.h: convert some macros to inlines Randy Dunlap
2007-12-10  8:34       ` Ingo Molnar
2007-12-05  7:15 ` [patch 08/18] fb: defio nopage npiggin
2007-12-05  7:15 ` [patch 09/18] agp: alpha nopage npiggin
2007-12-05  7:15 ` [patch 10/18] sg: nopage npiggin
2008-02-08  3:45   ` Douglas Gilbert
2007-12-05  7:15 ` [patch 11/18] ib: nopage npiggin
2007-12-05  7:15 ` [patch 12/18] usb: mon nopage npiggin
2007-12-05 16:39   ` Pete Zaitcev
2007-12-05 23:54     ` Nick Piggin
2007-12-05  7:16 ` [patch 13/18] alsa: nopage npiggin
2007-12-13 15:35   ` Takashi Iwai
2007-12-05  7:16 ` [patch 14/18] oss: via nopage npiggin
2007-12-05  7:16 ` [patch 15/18] alsa: usx2y nopage npiggin
2007-12-13 15:35   ` Takashi Iwai
2007-12-05  7:16 ` npiggin [this message]
2007-12-05  7:16 ` [patch 17/18] mm: remove nopage npiggin
2007-12-05 22:47   ` Andrew Morton
2007-12-05 23:23     ` Nick Piggin

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