[PATCH] even number of kmap types

[PATCH] even number of kmap types

[Hugh Dickins]

Extend the warning comment in kmap_types.h: if you add an odd number of
new kmaps, KM_VSTACK0 becomes misaligned on odd numbered cpus.  I've not
added a corresponding BUG_ON to entry_trampoline.c, having an aversion
to errors which trigger too early to be seen.  We should do better,
perhaps #error, or robustifying the layout; but for now just comment.

Hugh

--- 2.6.0-test4-mm3-1/include/asm-i386/kmap_types.h	Fri Aug 29 16:31:40 2003
+++ linux/include/asm-i386/kmap_types.h	Fri Aug 29 20:53:33 2003
@@ -5,8 +5,8 @@
 
 enum km_type {
 	/*
-	 * IMPORTANT: dont move these 3 entries, the virtual stack
-	 * must be 8K aligned.
+	 * IMPORTANT: don't move these 3 entries, and only add entries in
+	 * pairs: the 4G/4G virtual stack must be 8K aligned on each cpu.
 	 */
 	KM_BOUNCE_READ,
 	KM_VSTACK1,
@@ -29,6 +29,10 @@
 	KM_IRQ1,
 	KM_SOFTIRQ0,
 	KM_SOFTIRQ1,
+	/*
+	 * Add new entries in pairs:
+	 * the 4G/4G virtual stack must be 8K aligned on each cpu.
+	 */
 	KM_TYPE_NR
 };
 #endif