commit b1c02d9110e72ec510ec9b038f9564e3c0d87384
author Michael Ernst <mernst@de.ibm.com> Mon Jul 14 09:57:24 2008 +0200
committer Heiko Carstens <heiko.carstens@de.ibm.com> Mon Jul 14 10:01:59 2008 +0200
tree 7c7e75d9230ffbbc29e7424736973f79cbdf50ba
parent 9689b336e193680fc0fcaa33829dc670637e9c98

[S390] cio: Use locks when accessing /sys/firmware/cpi data.

Mutex locks are used to avoid problems when /sys/firmware/cpi data
are accessed to in parallel.

Signed-off-by: Michael Ernst <mernst@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

drivers/s390/char/sclp_cpi_sys.c

diff --git a/drivers/s390/char/sclp_cpi_sys.c b/drivers/s390/char/sclp_cpi_sys.c
index 9f37456..005f330 100644
--- a/drivers/s390/char/sclp_cpi_sys.c
+++ b/drivers/s390/char/sclp_cpi_sys.c
@@ -27,6 +27,8 @@
 #define CPI_LENGTH_NAME 8
 #define CPI_LENGTH_LEVEL 16
 
+static DEFINE_MUTEX(sclp_cpi_mutex);
+
 struct cpi_evbuf {
 	struct evbuf_header header;
 	u8	id_format;
@@ -223,7 +225,12 @@
 static ssize_t system_name_show(struct kobject *kobj,
 				struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%s\n", system_name);
+	int rc;
+
+	mutex_lock(&sclp_cpi_mutex);
+	rc = snprintf(page, PAGE_SIZE, "%s\n", system_name);
+	mutex_unlock(&sclp_cpi_mutex);
+	return rc;
 }
 
 static ssize_t system_name_store(struct kobject *kobj,
@@ -237,7 +244,9 @@
 	if (rc)
 		return rc;
 
+	mutex_lock(&sclp_cpi_mutex);
 	set_string(system_name, buf);
+	mutex_unlock(&sclp_cpi_mutex);
 
 	return len;
 }
@@ -248,7 +257,12 @@
 static ssize_t sysplex_name_show(struct kobject *kobj,
 				 struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%s\n", sysplex_name);
+	int rc;
+
+	mutex_lock(&sclp_cpi_mutex);
+	rc = snprintf(page, PAGE_SIZE, "%s\n", sysplex_name);
+	mutex_unlock(&sclp_cpi_mutex);
+	return rc;
 }
 
 static ssize_t sysplex_name_store(struct kobject *kobj,
@@ -262,7 +276,9 @@
 	if (rc)
 		return rc;
 
+	mutex_lock(&sclp_cpi_mutex);
 	set_string(sysplex_name, buf);
+	mutex_unlock(&sclp_cpi_mutex);
 
 	return len;
 }
@@ -273,7 +289,12 @@
 static ssize_t system_type_show(struct kobject *kobj,
 				struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%s\n", system_type);
+	int rc;
+
+	mutex_lock(&sclp_cpi_mutex);
+	rc = snprintf(page, PAGE_SIZE, "%s\n", system_type);
+	mutex_unlock(&sclp_cpi_mutex);
+	return rc;
 }
 
 static ssize_t system_type_store(struct kobject *kobj,
@@ -287,7 +308,9 @@
 	if (rc)
 		return rc;
 
+	mutex_lock(&sclp_cpi_mutex);
 	set_string(system_type, buf);
+	mutex_unlock(&sclp_cpi_mutex);
 
 	return len;
 }
@@ -298,8 +321,11 @@
 static ssize_t system_level_show(struct kobject *kobj,
 				 struct kobj_attribute *attr, char *page)
 {
-	unsigned long long level = system_level;
+	unsigned long long level;
 
+	mutex_lock(&sclp_cpi_mutex);
+	level = system_level;
+	mutex_unlock(&sclp_cpi_mutex);
 	return snprintf(page, PAGE_SIZE, "%#018llx\n", level);
 }
 
@@ -320,8 +346,9 @@
 	if (*endp)
 		return -EINVAL;
 
+	mutex_lock(&sclp_cpi_mutex);
 	system_level = level;
-
+	mutex_unlock(&sclp_cpi_mutex);
 	return len;
 }
 
@@ -334,7 +361,9 @@
 {
 	int rc;
 
+	mutex_lock(&sclp_cpi_mutex);
 	rc = cpi_req();
+	mutex_unlock(&sclp_cpi_mutex);
 	if (rc)
 		return rc;
 
@@ -373,12 +402,16 @@
 	if (rc)
 		return rc;
 
+	mutex_lock(&sclp_cpi_mutex);
 	set_string(system_name, system);
 	set_string(sysplex_name, sysplex);
 	set_string(system_type, type);
 	system_level = level;
 
-	return cpi_req();
+	rc = cpi_req();
+	mutex_unlock(&sclp_cpi_mutex);
+
+	return rc;
 }
 EXPORT_SYMBOL(sclp_cpi_set_data);