From 7cbab9dafa4f803b27a7ff3273e0ce988b0aa8be Mon Sep 17 00:00:00 2001
From: Alex Hornung <ahornung@gmail.com>
Date: Wed, 5 Aug 2009 19:29:45 +0100
Subject: [PATCH] DEVFS - change the rdev allocator to consider minor

Add a unique id to each dev ops in use and use this one and the minor
to construct the rdev.
---
 sys/kern/kern_conf.c       |  2 +-
 sys/sys/device.h           |  7 ++++---
 sys/vfs/devfs/devfs.h      |  3 +++
 sys/vfs/devfs/devfs_core.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 4 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
index ebccb53b11..e776db7c48 100644
--- a/sys/kern/kern_conf.c
+++ b/sys/kern/kern_conf.c
@@ -249,7 +249,7 @@ makeudev(int x, int y)
 {
 	if ((x & 0xffffff00) || (y & 0x0000ff00))
 		return NOUDEV;
-        return ((x << 8) | y);
+	return ((x << 8) | y);
 }
 
 /*
diff --git a/sys/sys/device.h b/sys/sys/device.h
index dbd794d6bc..c12a886bab 100644
--- a/sys/sys/device.h
+++ b/sys/sys/device.h
@@ -207,10 +207,11 @@ typedef int d_revoke_t (struct dev_revoke_args *ap);
 struct dev_ops {
 	struct {
 		const char	*name;	/* base name, e.g. 'da' */
-		int		maj;	/* major device number */
+		int			maj;	/* major device number */
 		u_int		flags;	/* D_XXX flags */
-		void            *data;	/* custom driver data */
-		int             refs;	/* ref count */
+		void		*data;	/* custom driver data */
+		int			refs;	/* ref count */
+		int			id;
 	} head;
 
 #define dev_ops_first_field	d_default
diff --git a/sys/vfs/devfs/devfs.h b/sys/vfs/devfs/devfs.h
index b4920e2989..760618f057 100644
--- a/sys/vfs/devfs/devfs.h
+++ b/sys/vfs/devfs/devfs.h
@@ -413,5 +413,8 @@ int devfs_clr_subnames_flag(char *, uint32_t);
 int devfs_destroy_subnames_without_flag(char *, uint32_t);
 int devfs_node_is_accessible(struct devfs_node *);
 
+int devfs_reference_ops(struct dev_ops *);
+void devfs_release_ops(struct dev_ops *);
+
 void devfs_config(void *);
 #endif /* _VFS_DEVFS_H_ */
diff --git a/sys/vfs/devfs/devfs_core.c b/sys/vfs/devfs/devfs_core.c
index e77f5266f2..2fd32a9159 100644
--- a/sys/vfs/devfs/devfs_core.c
+++ b/sys/vfs/devfs/devfs_core.c
@@ -45,11 +45,12 @@
 #include <sys/ucred.h>
 #include <sys/param.h>
 #include <sys/sysref2.h>
+#include <sys/systm.h>
 #include <vfs/devfs/devfs.h>
 #include <vfs/devfs/devfs_rules.h>
 
 MALLOC_DEFINE(M_DEVFS, "devfs", "Device File System (devfs) allocations");
-
+DEVFS_DECLARE_CLONE_BITMAP(ops_id);
 /*
  * SYSREF Integration - reference counting, allocation,
  * sysid and syslink integration.
@@ -2159,7 +2160,7 @@ devfs_new_cdev(struct dev_ops *ops, int minor)
 	dev->si_flags = 0;
 	dev->si_umajor = 0;
 	dev->si_uminor = minor;
-	dev->si_inode = devfs_fetch_ino();
+	dev->si_inode = makeudev(devfs_reference_ops(ops), minor);
 
 	return dev;
 }
@@ -2184,6 +2185,8 @@ devfs_cdev_terminate(cdev_t dev)
 	if (locked)
 		lockmgr(&devfs_lock, LK_RELEASE);
 
+	devfs_release_ops(dev->si_ops);
+
 	/* Finally destroy the device */
 	sysref_put(&dev->si_sysref);
 }
@@ -2227,6 +2230,34 @@ devfs_node_is_accessible(struct devfs_node *node)
 		return 0;
 }
 
+int
+devfs_reference_ops(struct dev_ops *ops)
+{
+	int unit;
+
+	if (ops->head.refs == 0) {
+		ops->head.id = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(ops_id), 255);
+		if (ops->head.id == -1) {
+			/* Ran out of unique ids */
+			kprintf("devfs_reference_ops: WARNING: ran out of unique ids\n");
+		}
+	}
+	unit = ops->head.id;
+	++ops->head.refs;
+
+	return unit;
+}
+
+void
+devfs_release_ops(struct dev_ops *ops)
+{
+	--ops->head.refs;
+
+	if (ops->head.refs == 0) {
+		devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(ops_id), ops->head.id);
+	}
+}
+
 void
 devfs_config(void *arg)
 {
@@ -2267,6 +2298,11 @@ devfs_init(void)
 			objcache_malloc_free,
 			&devfs_dev_malloc_args );
 
+	devfs_clone_bitmap_init(&DEVFS_CLONE_BITMAP(ops_id));
+#if 0
+	devfs_clone_bitmap_set(&DEVFS_CLONE_BITMAP(ops_id), 0);
+#endif
+
 	/* Initialize the reply-only port which acts as a message drain */
 	lwkt_initport_replyonly(&devfs_dispose_port, devfs_msg_autofree_reply);
 
@@ -2296,6 +2332,8 @@ devfs_uninit(void)
 	tsleep(td_core/*devfs_id*/, 0, "devfsc", 0);
 	tsleep(td_core/*devfs_id*/, 0, "devfsc", 10000);
 
+	devfs_clone_bitmap_uninit(&DEVFS_CLONE_BITMAP(ops_id));
+
 	/* Destroy the objcaches */
 	objcache_destroy(devfs_msg_cache);
 	objcache_destroy(devfs_node_cache);
-- 
2.11.4.GIT