[PATCH 1/2] powerpc/fadump: return 0 on re-registration

When fadump is already registered return success.

Currently EEXIST is returned which is difficult to handle race-free in
userspace when shell scripts are used. If multiple writers are trying
to write '1' there is no difference in whichever succeeds so just
return 0 to all.

Signed-off-by: Michal Suchanek <redacted>
---
 arch/powerpc/kernel/fadump.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/kernel/fadump.c

b/arch/powerpc/kernel/fadump.c index 436aedf195ab..5a7355381dac 100644

--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c

@@ -1214,7 +1214,6 @@ static ssize_t fadump_register_store(struct

kobject *kobj, break;
 	case '1':
 		if (fw_dump.dump_registered == 1) {
-			ret = -EEXIST;
 			goto unlock_out;
 		}
 		/* Register Firmware-assisted dump */

---
  arch/powerpc/kernel/fadump.c | 17 +++++++++++++----
  1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 5a7355381dac..241eff0b5f76 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c

@@ -1161,10 +1161,15 @@ static ssize_t fadump_release_memory_store(struct kobject *kobj,
  					struct kobj_attribute *attr,
  					const char *buf, size_t count)
  {
+	int input = -1;
+
  	if (!fw_dump.dump_active)
  		return -EPERM;

-	if (buf[0] == '1') {
+	if (kstrtoint(buf, 0, &input))
+		return -EINVAL;
+
+	if (input == 1) {
  		/*
  		 * Take away the '/proc/vmcore'. We are releasing the dump
  		 * memory, hence it will not be valid anymore.

@@ -1198,21 +1203,25 @@ static ssize_t fadump_register_store(struct kobject *kobj,
  					const char *buf, size_t count)
  {
  	int ret = 0;
+	int input = -1;

  	if (!fw_dump.fadump_enabled || fdm_active)
  		return -EPERM;

+	if (kstrtoint(buf, 0, &input))
+		return -EINVAL;
+
  	mutex_lock(&fadump_mutex);

-	switch (buf[0]) {
-	case '0':
+	switch (input) {
+	case 0:
  		if (fw_dump.dump_registered == 0) {
  			goto unlock_out;
  		}
  		/* Un-register Firmware-assisted dump */
  		fadump_unregister_dump(&fdm);
  		break;
-	case '1':
+	case 1:
  		if (fw_dump.dump_registered == 1) {
  			goto unlock_out;
  		}