X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=mm%2Fhugetlb.c;h=61d380678030312f453c44e86631c3f9c0e49028;hb=974f7bc5781d3fc16e32d8908c6e48592e767dd2;hp=fbd1111ea1194fc106042d57d2115a743dce7ced;hpb=a5324343955997d1439f26518ddac567cd5d134b;p=mv-sheeva.git

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index fbd1111ea11..61d38067803 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -274,21 +274,22 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 {
 	pte_t *src_pte, *dst_pte, entry;
 	struct page *ptepage;
-	unsigned long addr = vma->vm_start;
-	unsigned long end = vma->vm_end;
+	unsigned long addr;
 
-	while (addr < end) {
+	for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
 		dst_pte = huge_pte_alloc(dst, addr);
 		if (!dst_pte)
 			goto nomem;
+		spin_lock(&src->page_table_lock);
 		src_pte = huge_pte_offset(src, addr);
-		BUG_ON(!src_pte || pte_none(*src_pte)); /* prefaulted */
-		entry = *src_pte;
-		ptepage = pte_page(entry);
-		get_page(ptepage);
-		add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
-		set_huge_pte_at(dst, addr, dst_pte, entry);
-		addr += HPAGE_SIZE;
+		if (src_pte && !pte_none(*src_pte)) {
+			entry = *src_pte;
+			ptepage = pte_page(entry);
+			get_page(ptepage);
+			add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
+			set_huge_pte_at(dst, addr, dst_pte, entry);
+		}
+		spin_unlock(&src->page_table_lock);
 	}
 	return 0;
 
@@ -301,6 +302,7 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 {
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long address;
+	pte_t *ptep;
 	pte_t pte;
 	struct page *page;
 
@@ -309,13 +311,21 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 	BUG_ON(end & ~HPAGE_MASK);
 
 	for (address = start; address < end; address += HPAGE_SIZE) {
-		pte = huge_ptep_get_and_clear(mm, address, huge_pte_offset(mm, address));
+		ptep = huge_pte_offset(mm, address);
+		if (! ptep)
+			/* This can happen on truncate, or if an
+			 * mmap() is aborted due to an error before
+			 * the prefault */
+			continue;
+
+		pte = huge_ptep_get_and_clear(mm, address, ptep);
 		if (pte_none(pte))
 			continue;
+
 		page = pte_page(pte);
 		put_page(page);
+		add_mm_counter(mm, rss,  - (HPAGE_SIZE / PAGE_SIZE));
 	}
-	add_mm_counter(mm, rss,  -((end - start) >> PAGE_SHIFT));
 	flush_tlb_range(vma, start, end);
 }
 
@@ -351,8 +361,6 @@ int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 			ret = -ENOMEM;
 			goto out;
 		}
-		if (! pte_none(*pte))
-			hugetlb_clean_stale_pgtable(pte);
 
 		idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
 			+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
@@ -386,6 +394,28 @@ out:
 	return ret;
 }
 
+/*
+ * On ia64 at least, it is possible to receive a hugetlb fault from a
+ * stale zero entry left in the TLB from earlier hardware prefetching.
+ * Low-level arch code should already have flushed the stale entry as
+ * part of its fault handling, but we do need to accept this minor fault
+ * and return successfully.  Whereas the "normal" case is that this is
+ * an access to a hugetlb page which has been truncated off since mmap.
+ */
+int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+			unsigned long address, int write_access)
+{
+	int ret = VM_FAULT_SIGBUS;
+	pte_t *pte;
+
+	spin_lock(&mm->page_table_lock);
+	pte = huge_pte_offset(mm, address);
+	if (pte && !pte_none(*pte))
+		ret = VM_FAULT_MINOR;
+	spin_unlock(&mm->page_table_lock);
+	return ret;
+}
+
 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 			struct page **pages, struct vm_area_struct **vmas,
 			unsigned long *position, int *length, int i)
@@ -396,6 +426,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	BUG_ON(!is_vm_hugetlb_page(vma));
 
 	vpfn = vaddr/PAGE_SIZE;
+	spin_lock(&mm->page_table_lock);
 	while (vaddr < vma->vm_end && remainder) {
 
 		if (pages) {
@@ -408,8 +439,13 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 			 * indexing below to work. */
 			pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
 
-			/* hugetlb should be locked, and hence, prefaulted */
-			WARN_ON(!pte || pte_none(*pte));
+			/* the hugetlb file might have been truncated */
+			if (!pte || pte_none(*pte)) {
+				remainder = 0;
+				if (!i)
+					i = -EFAULT;
+				break;
+			}
 
 			page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
 
@@ -427,7 +463,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		--remainder;
 		++i;
 	}
-
+	spin_unlock(&mm->page_table_lock);
 	*length = remainder;
 	*position = vaddr;