mm/zsmalloc: avoid unregister a NOT-registered zsmalloc zpool driver

After patch [1], the zs_exit is only called in module exit. So add __init/__exit to zs_init/zs_exit.

[1] mm/zsmalloc: avoid unregister a NOT-registered zsmalloc zpool driver

Signed-off-by Mahendran Ganesh <[email protected]>

---
 mm/zsmalloc.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

mm/zsmalloc.c +2 -2

index 3d2bb36..92af030 100644
@@ -881,7 +881,7 @@ static struct notifier_block zs_cpu_nb = {
 	.notifier_call = zs_cpu_notifier
 };
 
-static void zs_exit(void)
+static void __exit zs_exit(void)
 {
 	int cpu;
 

@@ -898,7 +898,7 @@ static void zs_exit(void)
 	cpu_notifier_register_done();
 }
 
-static int zs_init(void)
+static int __init zs_init(void)
 {
 	int cpu, ret;
 

Signature · 1 line

1.7.9.5

Now zsmalloc can be registered as a zpool driver into zpool when CONFIG_ZPOOL is enabled. During the init of zsmalloc, when error happens, we need to do cleanup. But in current code, it will unregister a not yet registered zsmalloc zpool driver(*zs_zpool_driver*).

This patch puts the cleanup in zs_init() instead of calling zs_exit() where it will unregister a not-registered zpool driver.

Signed-off-by Mahendran Ganesh <[email protected]>

---
 mm/zsmalloc.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

mm/zsmalloc.c +1 -3

index 839a48c..3d2bb36 100644
@@ -907,10 +907,8 @@ static int zs_init(void)
 	__register_cpu_notifier(&zs_cpu_nb);
 	for_each_online_cpu(cpu) {
 		ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-		if (notifier_to_errno(ret)) {
-			cpu_notifier_register_done();
+		if (notifier_to_errno(ret))
 			goto fail;
-		}
 	}
 
 	cpu_notifier_register_done();

@@ -920,8 +918,14 @@ static int zs_init(void)
 #endif
 
 	return 0;

Quoted 33 lines

Now zsmalloc can be registered as a zpool driver into zpool when CONFIG_ZPOOL is enabled. During the init of zsmalloc, when error happens, we need to do cleanup. But in current code, it will unregister a not yet registered zsmalloc zpool driver(*zs_zpool_driver*).

This patch puts the cleanup in zs_init() instead of calling zs_exit() where it will unregister a not-registered zpool driver.

Signed-off-by Mahendran Ganesh <[email protected]>

---
 mm/zsmalloc.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

mm/zsmalloc.c +1 -3

index 839a48c..3d2bb36 100644
@@ -907,10 +907,8 @@ static int zs_init(void)
 	__register_cpu_notifier(&zs_cpu_nb);
 	for_each_online_cpu(cpu) {
 		ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-		if (notifier_to_errno(ret)) {
-			cpu_notifier_register_done();
+		if (notifier_to_errno(ret))
 			goto fail;
-		}
 	}
 
 	cpu_notifier_register_done();

@@ -920,8 +918,14 @@ static int zs_init(void)
 #endif
 
 	return 0;

mm/zsmalloc.c static int zs_init(void) · line 929

Quoted 10 lines

mm/zsmalloc.c +7 -1

+
 fail:
-	zs_exit();
+	for_each_online_cpu(cpu)
+		zs_cpu_notifier(NULL, CPU_UP_CANCELED, (void *)(long)cpu);
+	__unregister_cpu_notifier(&zs_cpu_nb);
+
+	cpu_notifier_register_done();
+
 	return notifier_to_errno(ret);

so we duplicate same code, and there is a bit confusing part
now: zs_cpu_notifier(CPU_UP_CANCELED) and zs_cpu_notifier(CPU_DEAD) calls.

how about something like this?

Factor out zsmalloc cpu notifier unregistration code and call it from both zs_exit() and zs_init() error path.

Quoted 2 lines · Sergey Senozhatsky

Factor out zsmalloc cpu notifier unregistration code and call it from both zs_exit() and zs_init() error path.

I should had have a good sleep before posting this. shame on me!

v3

Signed-ogg-by Sergey Senozhatsky <[email protected]>

---

 mm/zsmalloc.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

mm/zsmalloc.c +10 -7

index b3b57ef..cd4efa1 100644
@@ -881,14 +881,10 @@ static struct notifier_block zs_cpu_nb = {
 	.notifier_call = zs_cpu_notifier
 };
 
-static void zs_exit(void)
+static void zs_unregister_cpu_notifier(void)
 {
 	int cpu;
 
-#ifdef CONFIG_ZPOOL
-	zpool_unregister_driver(&zs_zpool_driver);
-#endif
-
 	cpu_notifier_register_begin();
 
 	for_each_online_cpu(cpu)

@@ -898,6 +894,14 @@ static void zs_exit(void)
 	cpu_notifier_register_done();
 }
 
+static void zs_exit(void)
+{
+#ifdef CONFIG_ZPOOL
+	zpool_unregister_driver(&zs_zpool_driver);
+#endif
+	zs_unregister_cpu_notifier();
+}
+
 static int zs_init(void)
 {
 	int cpu, ret;

@@ -921,7 +925,7 @@ static int zs_init(void)
 
 	return 0;
 fail:
-	zs_exit();
+	zs_unregister_cpu_notifier();
 	return notifier_to_errno(ret);
 }
 
 
--

To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to [email protected]. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"[email protected]"> [email protected] </a>

Quoted 32 lines

Now zsmalloc can be registered as a zpool driver into zpool when CONFIG_ZPOOL is enabled. During the init of zsmalloc, when error happens, we need to do cleanup. But in current code, it will unregister a not yet registered zsmalloc zpool driver(*zs_zpool_driver*).

This patch puts the cleanup in zs_init() instead of calling zs_exit() where it will unregister a not-registered zpool driver.

Signed-off-by Mahendran Ganesh <[email protected]>

---
 mm/zsmalloc.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

mm/zsmalloc.c +1 -3

index 839a48c..3d2bb36 100644
@@ -907,10 +907,8 @@ static int zs_init(void)
      __register_cpu_notifier(&zs_cpu_nb);
      for_each_online_cpu(cpu) {
              ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-             if (notifier_to_errno(ret)) {
-                     cpu_notifier_register_done();
+             if (notifier_to_errno(ret))
                      goto fail;
-             }
      }
 
      cpu_notifier_register_done();

@@ -920,8 +918,14 @@ static int zs_init(void)
 #endif
 

mm/zsmalloc.c static int zs_init(void) · line 929

Quoted 11 lines

mm/zsmalloc.c +7 -1

      return 0;
+
 fail:
-     zs_exit();
+     for_each_online_cpu(cpu)
+             zs_cpu_notifier(NULL, CPU_UP_CANCELED, (void *)(long)cpu);
+     __unregister_cpu_notifier(&zs_cpu_nb);
+
+     cpu_notifier_register_done();
+
      return notifier_to_errno(ret);

so we duplicate same code, and there is a bit confusing part
now: zs_cpu_notifier(CPU_UP_CANCELED) and zs_cpu_notifier(CPU_DEAD) calls.

how about something like this?

Factor out zsmalloc cpu notifier unregistration code and call it from both zs_exit() and zs_init() error path.

Signed-off-by Sergey Senozhatsky <[email protected]>

---

 mm/zsmalloc.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

mm/zsmalloc.c +10 -8

index b3b57ef..c4d2d60 100644
@@ -881,14 +881,10 @@ static struct notifier_block zs_cpu_nb = {
        .notifier_call = zs_cpu_notifier
 };
 
-static void zs_exit(void)
+static inline void zs_unregister_cpu_notifier()
 {
        int cpu;
 
-#ifdef CONFIG_ZPOOL
-       zpool_unregister_driver(&zs_zpool_driver);
-#endif
-
        cpu_notifier_register_begin();
 
        for_each_online_cpu(cpu)

@@ -898,6 +894,14 @@ static void zs_exit(void)
        cpu_notifier_register_done();
 }
 
+static void zs_exit(void)
+{
+#ifdef CONFIG_ZPOOL
+       zpool_unregister_driver(&zs_zpool_driver);
+#endif
+       zs_unregister_cpu_notifier();
+}
+
 static int zs_init(void)
 {
        int cpu, ret;

@@ -907,10 +911,8 @@ static int zs_init(void)
        __register_cpu_notifier(&zs_cpu_nb);
        for_each_online_cpu(cpu) {
                ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-               if (notifier_to_errno(ret)) {
-                       cpu_notifier_register_done();
+               if (notifier_to_errno(ret))
                        goto fail;
-               }
        }
 
        cpu_notifier_register_done();