linux: Clean up mm_pin/unpin.

Signed-off-by: Keir Fraser <keir@xensource.com>

2 files changed, 33 insertions, 28 deletions

diff --git a/linux-2.6-xen-sparse/arch/i386/mm/pgtable-xen.c b/linux-2.6-xen-sparse/arch/i386/mm/pgtable-xen.c
index 2cac785e50..4f72489800 100644
--- a/linux-2.6-xen-sparse/arch/i386/mm/pgtable-xen.c
+++ b/linux-2.6-xen-sparse/arch/i386/mm/pgtable-xen.c
@@ -573,64 +573,67 @@ void make_pages_writable(void *va, unsigned int nr, unsigned int feature)
 	}
 }
 
-static inline int pgd_walk_set_prot(struct page *page, pgprot_t flags)
+static inline void pgd_walk_set_prot(struct page *page, pgprot_t flags)
 {
 	unsigned long pfn = page_to_pfn(page);
+	int rc;
 
-	if (PageHighMem(page))
-		return pgprot_val(flags) & _PAGE_RW
-		       ? test_and_clear_bit(PG_pinned, &page->flags)
-		       : !test_and_set_bit(PG_pinned, &page->flags);
-
-	BUG_ON(HYPERVISOR_update_va_mapping(
-		(unsigned long)__va(pfn << PAGE_SHIFT),
-		pfn_pte(pfn, flags), 0));
-
-	return 0;
+	if (PageHighMem(page)) {
+		if (pgprot_val(flags) & _PAGE_RW)
+			clear_bit(PG_pinned, &page->flags);
+		else
+			set_bit(PG_pinned, &page->flags);
+	} else {
+		rc = HYPERVISOR_update_va_mapping(
+			(unsigned long)__va(pfn << PAGE_SHIFT),
+			pfn_pte(pfn, flags), 0);
+		if (rc)
+			BUG();
+	}
 }
 
-static int pgd_walk(pgd_t *pgd_base, pgprot_t flags)
+static void pgd_walk(pgd_t *pgd_base, pgprot_t flags)
 {
 	pgd_t *pgd = pgd_base;
 	pud_t *pud;
 	pmd_t *pmd;
-	int    g, u, m, flush;
+	int    g, u, m, rc;
 
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return 0;
 
-	for (g = 0, flush = 0; g < USER_PTRS_PER_PGD; g++, pgd++) {
+	for (g = 0; g < USER_PTRS_PER_PGD; g++, pgd++) {
 		if (pgd_none(*pgd))
 			continue;
 		pud = pud_offset(pgd, 0);
 		if (PTRS_PER_PUD > 1) /* not folded */
-			flush |= pgd_walk_set_prot(virt_to_page(pud),flags);
+			pgd_walk_set_prot(virt_to_page(pud),flags);
 		for (u = 0; u < PTRS_PER_PUD; u++, pud++) {
 			if (pud_none(*pud))
 				continue;
 			pmd = pmd_offset(pud, 0);
 			if (PTRS_PER_PMD > 1) /* not folded */
-				flush |= pgd_walk_set_prot(virt_to_page(pmd),flags);
+				pgd_walk_set_prot(virt_to_page(pmd),flags);
 			for (m = 0; m < PTRS_PER_PMD; m++, pmd++) {
 				if (pmd_none(*pmd))
 					continue;
-				flush |= pgd_walk_set_prot(pmd_page(*pmd),flags);
+				pgd_walk_set_prot(pmd_page(*pmd),flags);
 			}
 		}
 	}
 
-	BUG_ON(HYPERVISOR_update_va_mapping(
+	rc = HYPERVISOR_update_va_mapping(
 		(unsigned long)pgd_base,
 		pfn_pte(virt_to_phys(pgd_base)>>PAGE_SHIFT, flags),
-		UVMF_TLB_FLUSH));
-
-	return flush;
+		UVMF_TLB_FLUSH);
+	if (rc)
+		BUG();
 }
 
 static void __pgd_pin(pgd_t *pgd)
 {
-	if (pgd_walk(pgd, PAGE_KERNEL_RO))
-		kmap_flush_unused();
+	pgd_walk(pgd, PAGE_KERNEL_RO);
+	kmap_flush_unused();
 	xen_pgd_pin(__pa(pgd));
 	set_bit(PG_pinned, &virt_to_page(pgd)->flags);
 }
@@ -638,8 +641,7 @@ static void __pgd_pin(pgd_t *pgd)
 static void __pgd_unpin(pgd_t *pgd)
 {
 	xen_pgd_unpin(__pa(pgd));
-	if (pgd_walk(pgd, PAGE_KERNEL))
-		kmap_flush_unused();
+	pgd_walk(pgd, PAGE_KERNEL);
 	clear_bit(PG_pinned, &virt_to_page(pgd)->flags);
 }
 
diff --git a/linux-2.6-xen-sparse/arch/x86_64/mm/pageattr-xen.c b/linux-2.6-xen-sparse/arch/x86_64/mm/pageattr-xen.c
index a0f1d0535d..ae434e6be4 100644
--- a/linux-2.6-xen-sparse/arch/x86_64/mm/pageattr-xen.c
+++ b/linux-2.6-xen-sparse/arch/x86_64/mm/pageattr-xen.c
@@ -24,10 +24,13 @@ static inline void mm_walk_set_prot(void *pt, pgprot_t flags)
 {
 	struct page *page = virt_to_page(pt);
 	unsigned long pfn = page_to_pfn(page);
+	int rc;
 
-	BUG_ON(HYPERVISOR_update_va_mapping(
-		       (unsigned long)__va(pfn << PAGE_SHIFT),
-		       pfn_pte(pfn, flags), 0));
+	rc = HYPERVISOR_update_va_mapping(
+		(unsigned long)__va(pfn << PAGE_SHIFT),
+		pfn_pte(pfn, flags), 0);
+	if (rc)
+		BUG();
 }
 
 static void mm_walk(struct mm_struct *mm, pgprot_t flags)