[PATCH 06/18] driver: add new cdev_is_partition helper

[Ahmad Fatoum]

Partitions will have cdev->master != NULL, so often code will just do
if (cdev->master) to check if a cdev is a partition. This is suboptimal
as it may be misinterpreted by readers as meaning that the cdev is the
master device, while it's the other way round.

Let's define cdev_is_partition instead and use it everywhere, where
cdev->master is only checked, but not dereferenced.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 drivers/base/driver.c |  2 +-
 fs/devfs-core.c       | 10 +++++-----
 include/driver.h      |  4 ++++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index f00be99cdcbf..10d765e1a213 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -277,7 +277,7 @@ int unregister_device(struct device *old_dev)
 	}
 
 	list_for_each_entry_safe(cdev, ct, &old_dev->cdevs, devices_list) {
-		if (cdev->master) {
+		if (cdev_is_partition(cdev)) {
 			dev_dbg(old_dev, "unregister part %s\n", cdev->name);
 			devfs_del_partition(cdev->name);
 		}
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index fbcf68e81597..bb66993b90f9 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -38,7 +38,7 @@ int devfs_partition_complete(struct string_list *sl, char *instr)
 	len = strlen(instr);
 
 	for_each_cdev(cdev) {
-		if (cdev->master &&
+		if (cdev_is_partition(cdev) &&
 		    !strncmp(instr, cdev->name, len)) {
 			string_list_add_asprintf(sl, "%s ", cdev->name);
 		}
@@ -101,7 +101,7 @@ struct cdev *cdev_by_partuuid(const char *partuuid)
 		return NULL;
 
 	for_each_cdev(cdev) {
-		if (cdev->master && !strcasecmp(cdev->uuid, partuuid))
+		if (cdev_is_partition(cdev) && !strcasecmp(cdev->uuid, partuuid))
 			return cdev;
 	}
 	return NULL;
@@ -115,7 +115,7 @@ struct cdev *cdev_by_diskuuid(const char *diskuuid)
 		return NULL;
 
 	for_each_cdev(cdev) {
-		if (!cdev->master && !strcasecmp(cdev->uuid, diskuuid))
+		if (!cdev_is_partition(cdev) && !strcasecmp(cdev->uuid, diskuuid))
 			return cdev;
 	}
 	return NULL;
@@ -393,7 +393,7 @@ int devfs_remove(struct cdev *cdev)
 	list_for_each_entry_safe(c, tmp, &cdev->links, link_entry)
 		devfs_remove(c);
 
-	if (cdev->master)
+	if (cdev_is_partition(cdev))
 		list_del(&cdev->partition_entry);
 
 	if (cdev->link)
@@ -549,7 +549,7 @@ int devfs_del_partition(const char *name)
 		return ret;
 	}
 
-	if (!cdev->master)
+	if (!cdev_is_partition(cdev))
 		return -EINVAL;
 	if (cdev->flags & DEVFS_PARTITION_FIXED)
 		return -EPERM;
diff --git a/include/driver.h b/include/driver.h
index e1ee3dc2dd7c..00b4a0e4af75 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -564,6 +564,10 @@ int cdev_discard_range(struct cdev*, loff_t count, loff_t offset);
 int cdev_memmap(struct cdev*, void **map, int flags);
 int cdev_truncate(struct cdev*, size_t size);
 loff_t cdev_unallocated_space(struct cdev *cdev);
+static inline bool cdev_is_partition(const struct cdev *cdev)
+{
+	return cdev->master != NULL;
+}
 
 extern struct list_head cdev_list;
 #define for_each_cdev(cdev) \
-- 
2.39.2