[PATCH 07/18] cdev: alias: add support for partition links

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

We currently support bootsource.2, but not bootsource.root-A.
Fix this and while at it, factor out the logic for general reuse.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 common/cdev-alias.c | 22 +++-------------------
 fs/devfs-core.c     | 29 +++++++++++++++++++++++++++++
 include/driver.h    |  1 +
 3 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/common/cdev-alias.c b/common/cdev-alias.c
index 5c37c2e58bf3..09e6770f5dea 100644
--- a/common/cdev-alias.c
+++ b/common/cdev-alias.c
@@ -17,22 +17,6 @@ struct cdev_alias {
 		       cdev_alias_processor_t fn, void *data);
 };
 
-static struct cdev *resolve_partition(struct cdev *cdev,
-				      const char *partname)
-{
-	struct cdev *partcdev;
-
-	if (!partname)
-		return cdev;
-
-	for_each_cdev_partition(partcdev, cdev) {
-		if (streq_ptr(partcdev->partname, partname))
-			return partcdev;
-	}
-
-	return ERR_PTR(-ENODEV);
-}
-
 static int cdev_alias_resolve_bootsource(struct cdev_alias *cdev_alias,
 					 const char *partname,
 					 cdev_alias_processor_t fn,
@@ -44,9 +28,9 @@ static int cdev_alias_resolve_bootsource(struct cdev_alias *cdev_alias,
 	if (!cdev)
 		return -ENODEV;
 
-	cdev = resolve_partition(cdev, partname);
-	if (IS_ERR(cdev))
-		return PTR_ERR(cdev);
+	cdev = cdev_find_partition(cdev, partname);
+	if (!cdev)
+		return -ENODEV;
 
 	return fn(cdev, data);
 }
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index c69c38d6506e..e32bce9e307e 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -21,6 +21,7 @@
 #include <malloc.h>
 #include <ioctl.h>
 #include <nand.h>
+#include <string.h>
 #include <linux/err.h>
 #include <linux/fs.h>
 #include <linux/mtd/mtd.h>
@@ -149,6 +150,34 @@ cdev_find_child_by_gpt_typeuuid(struct cdev *cdev, const guid_t *typeuuid)
 	return ERR_PTR(-ENOENT);
 }
 
+/**
+ * cdev_find_partition - find a partition belonging to a physical device
+ *
+ * @cdev: the cdev which should be searched for partitions
+ * @name: the partition name
+ */
+struct cdev *cdev_find_partition(struct cdev *cdevm, const char *name)
+{
+	struct cdev *partcdev;
+
+	if (!name)
+		return cdevm;
+
+	for_each_cdev_partition(partcdev, cdevm) {
+		struct cdev *cdevl;
+
+		if (streq_ptr(partcdev->partname, name))
+			return partcdev;
+
+		list_for_each_entry(cdevl, &partcdev->links, link_entry) {
+			if (streq_ptr(cdevl->partname, name))
+				return cdevl;
+		}
+	}
+
+	return NULL;
+}
+
 /**
  * device_find_partition - find a partition belonging to a physical device
  *
diff --git a/include/driver.h b/include/driver.h
index 3f2c681c0e80..ca002c5164c2 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -503,6 +503,7 @@ int devfs_create(struct cdev *);
 int devfs_create_link(struct cdev *, const char *name);
 int devfs_remove(struct cdev *);
 int cdev_find_free_index(const char *);
+struct cdev *cdev_find_partition(struct cdev *cdevm, const char *name);
 struct cdev *device_find_partition(struct device *dev, const char *name);
 struct cdev *lcdev_by_name(const char *filename);
 struct cdev *cdev_readlink(struct cdev *cdev);
-- 
2.39.5