Add a new function devfs_dev_exists() to be able to find out if a

specific devfs path already exists.

The function will be used from kern_conf.c to detect duplicate device
registrations. Callers must hold the devmtx mutex.

Reviewed by:	kib

2 files changed, 22 insertions, 0 deletions

diff --git a/sys/fs/devfs/devfs_devs.c b/sys/fs/devfs/devfs_devs.c
index 99b33ec..52e6567 100644
--- a/sys/fs/devfs/devfs_devs.c
+++ b/sys/fs/devfs/devfs_devs.c
@@ -142,6 +142,27 @@ devfs_alloc(int flags)
 	return (cdev);
 }
 
+int
+devfs_dev_exists(const char *name)
+{
+	struct cdev_priv *cdp;
+
+	mtx_assert(&devmtx, MA_OWNED);
+
+	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
+		if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
+			continue;
+		if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
+			return (1);
+		if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
+			return (1);
+	}
+	if (devfs_dir_find(name) != 0)
+		return (1);
+
+	return (0);
+}
+
 void
 devfs_free(struct cdev *cdev)
 {
diff --git a/sys/fs/devfs/devfs_int.h b/sys/fs/devfs/devfs_int.h
index cd58284..df16f18 100644
--- a/sys/fs/devfs/devfs_int.h
+++ b/sys/fs/devfs/devfs_int.h
@@ -72,6 +72,7 @@ struct cdev_priv {
 #define	cdev2priv(c)	member2struct(cdev_priv, cdp_c, c)
 
 struct cdev *devfs_alloc(int);
+int devfs_dev_exists(const char *);
 void devfs_free(struct cdev *);
 void devfs_create(struct cdev *dev);
 void devfs_destroy(struct cdev *dev);