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authorJan Beulich <jbeulich@novell.com>2008-12-16 11:35:24 +0000
committerIngo Molnar <mingo@elte.hu>2008-12-16 18:34:51 +0100
commit1796316a8b028a148be48ba5d4e7be493a39d173 (patch)
tree628848bb98909632bbb503b1db27c2a6db9291e6 /mm
parent9470565579f29486f4ed0ffa50774268b64994b0 (diff)
downloadlinux-2.6.34-ux500-1796316a8b028a148be48ba5d4e7be493a39d173.tar.gz
x86: consolidate __swp_XXX() macros
Impact: cleanup, code robustization The __swp_...() macros silently relied upon which bits are used for _PAGE_FILE and _PAGE_PROTNONE. After having changed _PAGE_PROTNONE in our Xen kernel to no longer overlap _PAGE_PAT, live locks and crashes were reported that could have been avoided if these macros properly used the symbolic constants. Since, as pointed out earlier, for Xen Dom0 support mainline likewise will need to eliminate the conflict between _PAGE_PAT and _PAGE_PROTNONE, this patch does all the necessary adjustments, plus it introduces a mechanism to check consistency between MAX_SWAPFILES_SHIFT and the actual encoding macros. This also fixes a latent bug in that x86-64 used a 6-bit mask in __swp_type(), and if MAX_SWAPFILES_SHIFT was increased beyond 5 in (the seemingly unrelated) linux/swap.h, this would have resulted in a collision with _PAGE_FILE. Non-PAE 32-bit code gets similarly adjusted for its pte_to_pgoff() and pgoff_to_pte() calculations. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'mm')
-rw-r--r--mm/swapfile.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 90cb67a5417..54a9f87e516 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1462,6 +1462,15 @@ static int __init procswaps_init(void)
__initcall(procswaps_init);
#endif /* CONFIG_PROC_FS */
+#ifdef MAX_SWAPFILES_CHECK
+static int __init max_swapfiles_check(void)
+{
+ MAX_SWAPFILES_CHECK();
+ return 0;
+}
+late_initcall(max_swapfiles_check);
+#endif
+
/*
* Written 01/25/92 by Simmule Turner, heavily changed by Linus.
*