[PATCH v11 1/2] binderfs: add new binder devices to binder_devices

Li Li
2024-12-18T20:37:49Z

From: Li Li <dualli@google.com>

When binderfs is not enabled, the binder driver parses the kernel
config to create all binder devices. All of the new binder devices
are stored in the list binder_devices.

When binderfs is enabled, the binder driver creates new binder devices
dynamically when userspace applications call BINDER_CTL_ADD ioctl. But
the devices created in this way are not stored in the same list.

This patch fixes that.

Signed-off-by: Li Li <dualli@google.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
---
drivers/android/binder.c | 5 +++++
drivers/android/binder_internal.h | 11 +++++++++--
drivers/android/binderfs.c | 2 ++
3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index ef353ca13c35..0a16acd29653 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -6928,6 +6928,11 @@ const struct binder_debugfs_entry binder_debugfs_entries[] = {
{} /* terminator */
};

+void binder_add_device(struct binder_device *device)
+{
+ hlist_add_head(&device->hlist, &binder_devices);
+}
+
static int __init init_binder_device(const char *name)
{
int ret;
diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
index f8d6be682f23..e4eb8357989c 100644
--- a/drivers/android/binder_internal.h
+++ b/drivers/android/binder_internal.h
@@ -25,8 +25,7 @@ struct binder_context {

/**
* struct binder_device - information about a binder device node
- * @hlist: list of binder devices (only used for devices requested via
- * CONFIG_ANDROID_BINDER_DEVICES)
+ * @hlist: list of binder devices
* @miscdev: information about a binder character device node
* @context: binder context information
* @binderfs_inode: This is the inode of the root dentry of the super block
@@ -582,4 +581,12 @@ struct binder_object {
};
};

+/**
+ * Add a binder device to binder_devices
+ * @device: the new binder device to add to the global list
+ *
+ * Not reentrant as the list is not protected by any locks
+ */
+void binder_add_device(struct binder_device *device);
+
#endif /* _LINUX_BINDER_INTERNAL_H */
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index ad1fa7abc323..bc6bae76ccaf 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -207,6 +207,8 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
fsnotify_create(root->d_inode, dentry);
inode_unlock(d_inode(root));

+ binder_add_device(device);
+
return 0;

err:
--
2.47.1.613.gc27f4b7a9f-goog