linux-kernel - [x86_64] Use lru instead of page->index and page->private for pgd lists management.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Mon, 26 Mar 2007 11:23:18 -0700 (PDT)
From:	Christoph Lameter <clameter@....com>
To:	ak@...e.de
cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: [x86_64] Use lru instead of page->index and page->private for pgd
 lists management.

x86_64 currently simulates a list using the index and private fields of the page struct.
Seems that the code was inherited from i386. But x86_64 does not use the slab to
allocate pgds and pmds etc. So the lru field is not used by the slab and therefore
available.

This patch uses standard list operations on page->lru to realize pgd tracking.

Signed-off-by: Christoph Lameter <clameter@....com>

Index: linux-2.6.21-rc4/arch/x86_64/mm/fault.c
===================================================================
--- linux-2.6.21-rc4.orig/arch/x86_64/mm/fault.c	2007-03-26 11:03:46.000000000 -0700
+++ linux-2.6.21-rc4/arch/x86_64/mm/fault.c	2007-03-26 11:04:43.000000000 -0700
@@ -585,7 +585,7 @@
 }
 
 DEFINE_SPINLOCK(pgd_lock);
-struct page *pgd_list;
+LIST_HEAD(pgd_list);
 
 void vmalloc_sync_all(void)
 {
@@ -605,8 +605,7 @@
 			if (pgd_none(*pgd_ref))
 				continue;
 			spin_lock(&pgd_lock);
-			for (page = pgd_list; page;
-			     page = (struct page *)page->index) {
+			list_for_each_entry(page, &pgd_list, lru) {
 				pgd_t *pgd;
 				pgd = (pgd_t *)page_address(page) + pgd_index(address);
 				if (pgd_none(*pgd))
Index: linux-2.6.21-rc4/include/asm-x86_64/pgtable.h
===================================================================
--- linux-2.6.21-rc4.orig/include/asm-x86_64/pgtable.h	2007-03-26 11:03:46.000000000 -0700
+++ linux-2.6.21-rc4/include/asm-x86_64/pgtable.h	2007-03-26 11:04:43.000000000 -0700
@@ -403,7 +403,7 @@
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
 extern spinlock_t pgd_lock;
-extern struct page *pgd_list;
+extern struct list_head pgd_list;
 void vmalloc_sync_all(void);
 
 #endif /* !__ASSEMBLY__ */
Index: linux-2.6.21-rc4/include/asm-x86_64/pgalloc.h
===================================================================
--- linux-2.6.21-rc4.orig/include/asm-x86_64/pgalloc.h	2007-03-26 11:04:52.000000000 -0700
+++ linux-2.6.21-rc4/include/asm-x86_64/pgalloc.h	2007-03-26 11:08:11.000000000 -0700
@@ -45,24 +45,16 @@
 	struct page *page = virt_to_page(pgd);
 
 	spin_lock(&pgd_lock);
-	page->index = (pgoff_t)pgd_list;
-	if (pgd_list)
-		pgd_list->private = (unsigned long)&page->index;
-	pgd_list = page;
-	page->private = (unsigned long)&pgd_list;
+	list_add(&page->lru, &pgd_list);
 	spin_unlock(&pgd_lock);
 }
 
 static inline void pgd_list_del(pgd_t *pgd)
 {
-	struct page *next, **pprev, *page = virt_to_page(pgd);
+	struct page *page = virt_to_page(pgd);
 
 	spin_lock(&pgd_lock);
-	next = (struct page *)page->index;
-	pprev = (struct page **)page->private;
-	*pprev = next;
-	if (next)
-		next->private = (unsigned long)pprev;
+	list_del(&page->lru);
 	spin_unlock(&pgd_lock);
 }
 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/