Add MAKEDEV_NOWAIT flag to make_dev_credf(9), to create a device node

in a no-sleep context. If resource allocation cannot be done without
sleep, make_dev_credf() fails and returns NULL.

Reviewed by:	jh
MFC after:	2 weeks

2 files changed, 8 insertions, 3 deletions

diff --git a/sys/fs/devfs/devfs_devs.c b/sys/fs/devfs/devfs_devs.c
index 81b2752..4bd6728 100644
--- a/sys/fs/devfs/devfs_devs.c
+++ b/sys/fs/devfs/devfs_devs.c
@@ -115,17 +115,21 @@ SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
     0, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)");
 
 struct cdev *
-devfs_alloc(void)
+devfs_alloc(int flags)
 {
 	struct cdev_priv *cdp;
 	struct cdev *cdev;
 	struct timespec ts;
 
-	cdp = malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO | M_WAITOK);
+	cdp = malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO |
+	    ((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK));
+	if (cdp == NULL)
+		return (NULL);
 
 	cdp->cdp_dirents = &cdp->cdp_dirent0;
 	cdp->cdp_dirent0 = NULL;
 	cdp->cdp_maxdirent = 0;
+	cdp->cdp_inode = 0;
 
 	cdev = &cdp->cdp_c;
 
@@ -133,6 +137,7 @@ devfs_alloc(void)
 	LIST_INIT(&cdev->si_children);
 	vfs_timestamp(&ts);
 	cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
+	cdev->si_cred = NULL;
 
 	return (cdev);
 }
diff --git a/sys/fs/devfs/devfs_int.h b/sys/fs/devfs/devfs_int.h
index 5a61dd4..f5612e1 100644
--- a/sys/fs/devfs/devfs_int.h
+++ b/sys/fs/devfs/devfs_int.h
@@ -70,7 +70,7 @@ struct cdev_priv {
 
 #define	cdev2priv(c)	member2struct(cdev_priv, cdp_c, c)
 
-struct cdev *devfs_alloc(void);
+struct cdev *devfs_alloc(int);
 void devfs_free(struct cdev *);
 void devfs_create(struct cdev *dev);
 void devfs_destroy(struct cdev *dev);