[PATCH] SMP alternatives: skip with UP kernels

Hide the magic in alternative.h and provide some dummy inline functions
for the UP case (gcc should manage to optimize away these calls).  No
changes in module.c.

Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index 50eb0e03777e4b1a7f0fe564f507b6ccfe358f18..7b421b3a053e0ce8827410566a601b7050a7ff76 100644 (file)
--- a/arch/i386/kernel/alternative.c
+++ b/arch/i386/kernel/alternative.c
@@ -168,6 +168,8 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
        }
 }
 
+#ifdef CONFIG_SMP
+
 static void alternatives_smp_save(struct alt_instr *start, struct alt_instr *end)
 {
        struct alt_instr *a;
@@ -328,6 +330,8 @@ void alternatives_smp_switch(int smp)
        spin_unlock_irqrestore(&smp_alt, flags);
 }
 
+#endif
+
 void __init alternative_instructions(void)
 {
        if (no_replacement) {
@@ -349,6 +353,7 @@ void __init alternative_instructions(void)
        smp_alt_once = 1;
 #endif
 
+#ifdef CONFIG_SMP
        if (smp_alt_once) {
                if (1 == num_possible_cpus()) {
                        printk(KERN_INFO "SMP alternatives: switching to UP code\n");
@@ -370,4 +375,5 @@ void __init alternative_instructions(void)
                                            _text, _etext);
                alternatives_smp_switch(0);
        }
+#endif
 }

diff --git a/include/asm-i386/alternative.h b/include/asm-i386/alternative.h
index c61bd1a17f3706a959b1b120977237ee65852628..96adbabec7406fe2c285baad3629257ac8579702 100644 (file)
--- a/include/asm-i386/alternative.h
+++ b/include/asm-i386/alternative.h
@@ -19,11 +19,19 @@ struct alt_instr {
 extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 
 struct module;
+#ifdef CONFIG_SMP
 extern void alternatives_smp_module_add(struct module *mod, char *name,
                                        void *locks, void *locks_end,
                                        void *text, void *text_end);
 extern void alternatives_smp_module_del(struct module *mod);
 extern void alternatives_smp_switch(int smp);
+#else
+static inline void alternatives_smp_module_add(struct module *mod, char *name,
+                                       void *locks, void *locks_end,
+                                       void *text, void *text_end) {}
+static inline void alternatives_smp_module_del(struct module *mod) {}
+static inline void alternatives_smp_switch(int smp) {}
+#endif
 
 #endif
 

diff --git a/include/asm-x86_64/alternative.h b/include/asm-x86_64/alternative.h
index 387c8f66af7d5d8b2e103d1f3c734b79e0589e53..aa67bfd1b3ce63a73a4f29467d9e5a664bcc1190 100644 (file)
--- a/include/asm-x86_64/alternative.h
+++ b/include/asm-x86_64/alternative.h
@@ -17,11 +17,20 @@ struct alt_instr {
 extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 
 struct module;
+
+#ifdef CONFIG_SMP
 extern void alternatives_smp_module_add(struct module *mod, char *name,
                                        void *locks, void *locks_end,
                                        void *text, void *text_end);
 extern void alternatives_smp_module_del(struct module *mod);
 extern void alternatives_smp_switch(int smp);
+#else
+static inline void alternatives_smp_module_add(struct module *mod, char *name,
+                                       void *locks, void *locks_end,
+                                       void *text, void *text_end) {}
+static inline void alternatives_smp_module_del(struct module *mod) {}
+static inline void alternatives_smp_switch(int smp) {}
+#endif
 
 #endif