dm-ima: more strlen() drops

Following commit ebbd176 ("dm: ima: avoid extra calls to
strlen()"), convert 'dm_ima_alloc_and_copy_capacity_str()' to
return the number of characters emitted by 'scnprintf()' and
simplify the users accordingly. Compile tested only.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Author: dmantipov

drivers/md/dm-ima.c

@@ -157,10 +157,8 @@ static int dm_ima_alloc_and_copy_capacity_str(struct mapped_device *md, char **c
 	if (!(*capacity_str))
 		return -ENOMEM;
 
-	scnprintf(*capacity_str, DM_IMA_DEVICE_BUF_LEN, "current_device_capacity=%llu;",
-		  capacity);
-
-	return 0;
+	return scnprintf(*capacity_str, DM_IMA_DEVICE_BUF_LEN, "current_device_capacity=%llu;",
+			 capacity);
 }
 
 /*
@@ -371,18 +369,18 @@ void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap)
 {
 	char *device_table_data, *dev_name = NULL, *dev_uuid = NULL, *capacity_str = NULL;
 	char active[] = "active_table_hash=";
-	unsigned int active_len = strlen(active), capacity_len = 0;
+	unsigned int active_len = strlen(active);
 	unsigned int l = 0;
 	bool noio = true;
 	bool nodata = true;
-	int r;
+	int capacity_len;
 
 	device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, GFP_KERNEL, noio);
 	if (!device_table_data)
 		return;
 
-	r = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
-	if (r)
+	capacity_len = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
+	if (capacity_len < 0)
 		goto error;
 
 	memcpy(device_table_data + l, DM_IMA_VERSION_STR, md->ima.dm_version_str_len);
@@ -445,16 +443,14 @@ void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap)
 	}
 
 	if (nodata) {
-		r = dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio);
-		if (r)
+		if (dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio))
 			goto error;
 
 		l = scnprintf(device_table_data, DM_IMA_DEVICE_BUF_LEN,
 			      "%sname=%s,uuid=%s;device_resume=no_data;",
 			      DM_IMA_VERSION_STR, dev_name, dev_uuid);
 	}
 
-	capacity_len = strlen(capacity_str);
 	memcpy(device_table_data + l, capacity_str, capacity_len);
 	l += capacity_len;
 
@@ -483,18 +479,17 @@ void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all)
 	unsigned int device_active_len = strlen(device_active_str);
 	unsigned int device_inactive_len = strlen(device_inactive_str);
 	unsigned int remove_all_len = strlen(remove_all_str);
-	unsigned int capacity_len = 0;
 	unsigned int l = 0;
 	bool noio = true;
 	bool nodata = true;
-	int r;
+	int capacity_len;
 
 	device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN*2, GFP_KERNEL, noio);
 	if (!device_table_data)
 		goto exit;
 
-	r = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
-	if (r) {
+	capacity_len = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
+	if (capacity_len < 0) {
 		kfree(device_table_data);
 		goto exit;
 	}
@@ -570,7 +565,6 @@ void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all)
 	memcpy(device_table_data + l, remove_all ? "y;" : "n;", 2);
 	l += 2;
 
-	capacity_len = strlen(capacity_str);
 	memcpy(device_table_data + l, capacity_str, capacity_len);
 	l += capacity_len;
 
@@ -602,20 +596,20 @@ void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all)
  */
 void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map)
 {
-	unsigned int l = 0, capacity_len = 0;
+	unsigned int l = 0;
 	char *device_table_data = NULL, *dev_name = NULL, *dev_uuid = NULL, *capacity_str = NULL;
 	char inactive_str[] = "inactive_table_hash=";
 	unsigned int inactive_len = strlen(inactive_str);
 	bool noio = true;
 	bool nodata = true;
-	int r;
+	int capacity_len;
 
 	device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, GFP_KERNEL, noio);
 	if (!device_table_data)
 		return;
 
-	r = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
-	if (r)
+	capacity_len = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
+	if (capacity_len < 0)
 		goto error1;
 
 	memcpy(device_table_data + l, DM_IMA_VERSION_STR, md->ima.dm_version_str_len);
@@ -650,7 +644,6 @@ void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map)
 			      DM_IMA_VERSION_STR, dev_name, dev_uuid);
 	}
 
-	capacity_len = strlen(capacity_str);
 	memcpy(device_table_data + l, capacity_str, capacity_len);
 	l += capacity_len;
 
@@ -703,7 +696,7 @@ void dm_ima_measure_on_device_rename(struct mapped_device *md)
 	char *old_device_data = NULL, *new_device_data = NULL, *combined_device_data = NULL;
 	char *new_dev_name = NULL, *new_dev_uuid = NULL, *capacity_str = NULL;
 	bool noio = true;
-	int r, len;
+	int len;
 
 	if (dm_ima_alloc_and_copy_device_data(md, &new_device_data,
 					      md->ima.active_table.num_targets, noio))
@@ -716,8 +709,7 @@ void dm_ima_measure_on_device_rename(struct mapped_device *md)
 	if (!combined_device_data)
 		goto error;
 
-	r = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
-	if (r)
+	if (dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio) < 0)
 		goto error;
 
 	old_device_data = md->ima.active_table.device_metadata;