xen/notifier: simplify using notifier_[to|from]_errno()

Today all users of notifier_from_errno() and notifier_to_errno() are
Handling the success case the same way, by using

  !rc ? NOTIFY_DONE : notifier_from_errno(rc)

or

  (notifier_rc == NOTIFY_DONE) ? 0 : notifier_to_errno(notifier_rc);

Simplify the use cases by moving the handling of the success case into
the functions.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com> # xen/common/sched/
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>

xen/arch/arm/cpuerrata.c

@@ -724,7 +724,7 @@ static int cpu_errata_callback(struct notifier_block *nfb,
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_errata_nfb = {

xen/arch/arm/gic-v3-lpi.c

@@ -402,7 +402,7 @@ static int cpu_callback(struct notifier_block *nfb, unsigned long action,
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/arm/irq.c

@@ -148,7 +148,7 @@ static int cpu_callback(struct notifier_block *nfb, unsigned long action,
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/arm/percpu.c

@@ -68,7 +68,7 @@ static int cpu_percpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_percpu_nfb = {

xen/arch/arm/smpboot.c

@@ -562,7 +562,7 @@ static int cpu_smpboot_callback(struct notifier_block *nfb,
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_smpboot_nfb = {

xen/arch/x86/acpi/cpu_idle.c

@@ -1663,7 +1663,7 @@ static int cf_check cpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/x86/cpu/mcheck/mce.c

@@ -757,7 +757,7 @@ static int cf_check cpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/x86/cpu/mcheck/mce_intel.c

@@ -951,7 +951,7 @@ static int cf_check cpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/x86/cpu/mwait-idle.c

@@ -1537,7 +1537,7 @@ static int cf_check mwait_idle_cpu_init(
 		dev = processor_powers[cpu];
 		if (!rc && cpuidle_current_governor->enable)
 			rc = cpuidle_current_governor->enable(dev);
-		return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+		return notifier_from_errno(rc);
 
 	case CPU_ONLINE:
 		if (!dev)

xen/arch/x86/genapic/x2apic.c

@@ -221,7 +221,7 @@ static int cf_check update_clusterinfo(
         break;
     }
 
-    return !err ? NOTIFY_DONE : notifier_from_errno(err);
+    return notifier_from_errno(err);
 }
 
 static struct notifier_block x2apic_cpu_nfb = {

xen/arch/x86/hvm/hvm.c

@@ -139,7 +139,7 @@ static int cf_check cpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/x86/percpu.c

@@ -86,7 +86,7 @@ static int cf_check cpu_percpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_percpu_nfb = {

xen/arch/x86/psr.c

@@ -1663,7 +1663,7 @@ static int cf_check cpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/arch/x86/smpboot.c

@@ -1144,7 +1144,7 @@ static int cf_check cpu_smpboot_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_smpboot_nfb = {

xen/common/cpu.c

@@ -82,7 +82,7 @@ static int cpu_notifier_call_chain(unsigned int cpu, unsigned long action,
 {
     void *hcpu = (void *)(long)cpu;
     int notifier_rc = notifier_call_chain(&cpu_chain, action, hcpu, nb);
-    int ret = (notifier_rc == NOTIFY_DONE) ? 0 : notifier_to_errno(notifier_rc);
+    int ret =  notifier_to_errno(notifier_rc);
 
     BUG_ON(ret && nofail);
 

xen/common/sched/core.c

@@ -2903,7 +2903,7 @@ static int cf_check cpu_schedule_callback(
 
     rcu_read_unlock(&sched_res_rculock);
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_schedule_nfb = {

xen/common/sched/cpupool.c

@@ -1074,7 +1074,7 @@ static int cf_check cpu_callback(
         break;
     }
 
-    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+    return notifier_from_errno(rc);
 }
 
 static struct notifier_block cpu_nfb = {

xen/include/xen/notifier.h

@@ -58,13 +58,13 @@ int notifier_call_chain(
 /* Encapsulate (negative) errno value. */
 static inline int notifier_from_errno(int err)
 {
-    return NOTIFY_STOP_MASK | -err;
+    return err ? (NOTIFY_STOP_MASK | -err) : NOTIFY_DONE;
 }
 
 /* Restore (negative) errno value from notify return value. */
 static inline int notifier_to_errno(int ret)
 {
-    return -(ret & ~NOTIFY_STOP_MASK);
+    return (ret == NOTIFY_DONE) ? 0 : -(ret & ~NOTIFY_STOP_MASK);
 }
 
 #endif /* __XEN_NOTIFIER_H__ */