Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b1d0e4f535e10775cffde922208b49629169aeaa
Commit: b1d0e4f535e10775cffde922208b49629169aeaa
Parent: 6a306e8b4c81a1c1f538e390d92bfe80d04b254c
Author: Nick Piggin <[EMAIL PROTECTED]>
AuthorDate: Sat Feb 9 01:15:19 2008 +0100
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Feb 8 18:57:39 2008 -0800
mm: special mapping nopage
Convert special mapping install from nopage to fault.
Because the "vm_file" is NULL for the special mapping, the generic VM
code has messed up "vm_pgoff" thinking that it's an anonymous mapping
and the offset does't matter. For that reason, we need to undo the
vm_pgoff offset that got added into vmf->pgoff.
[ We _really_ should clean that up - either by making this whole special
mapping code just use a real file entry rather than that ugly array of
"struct page" pointers, or by just making the VM code realize that
even if vm_file is NULL it may not be a regular anonymous mmap.
- Linus ]
Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
Cc: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
mm/mmap.c | 25 ++++++++++++++++---------
1 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index ad6e4ea..a32d28c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2165,24 +2165,31 @@ int may_expand_vm(struct mm_struct *mm, unsigned long
npages)
}
-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;
struct page **pages;
- BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+ /*
+ * special mappings have no vm_file, and in that case, the mm
+ * uses vm_pgoff internally. So we have to subtract it from here.
+ * We are allowed to do this because we are the mm; do not copy
+ * this code into drivers!
+ */
+ pgoff = vmf->pgoff - vma->vm_pgoff;
- 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;
}
/*
@@ -2194,7 +2201,7 @@ static void special_mapping_close(struct vm_area_struct
*vma)
static struct vm_operations_struct special_mapping_vmops = {
.close = special_mapping_close,
- .nopage = special_mapping_nopage,
+ .fault = special_mapping_fault,
};
/*
-
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