xnu-6153.11.26.tar.gz

[apple/xnu.git] / bsd / miscfs / devfs / devfs_tree.c

diff --git a/bsd/miscfs/devfs/devfs_tree.c b/bsd/miscfs/devfs/devfs_tree.c
index fe32a3c680b4cea0030b335634f51dec69367cb1..589472d570332840d155fd45d70a058b45c07663 100644 (file)
--- a/bsd/miscfs/devfs/devfs_tree.c
+++ b/bsd/miscfs/devfs/devfs_tree.c
@@ -99,6 +99,7 @@
 #include <sys/vnode_internal.h>
 #include <stdarg.h>
 #include <libkern/OSAtomic.h>
+#include <os/refcnt.h>
 #define BSD_KERNEL_PRIVATE      1       /* devfs_make_link() prototype */
 #include "devfs.h"
 #include "devfsdefs.h"
@@ -150,6 +151,8 @@ lck_attr_t      * devfs_lck_attr;
 lck_mtx_t         devfs_mutex;
 lck_mtx_t         devfs_attr_mutex;
 
+os_refgrp_decl(static, devfs_refgrp, "devfs", NULL);
+
 devdirent_t *           dev_root = NULL;        /* root of backing tree */
 struct devfs_stats      devfs_stats;            /* hold stats */
 
@@ -515,6 +518,7 @@ dev_add_node(int entrytype, devnode_type_t * typeinfo, devnode_t * proto,
     devnode_t * *dn_pp, struct devfsmount *dvm)
 {
        devnode_t *     dnp = NULL;
+       int     error = 0;
 
 #if defined SPLIT_DEVS
        /*
@@ -587,7 +591,9 @@ dev_add_node(int entrytype, devnode_type_t * typeinfo, devnode_t * proto,
 #endif
        }
        dnp->dn_dvm = dvm;
-       dnp->dn_refcount = 0;
+
+       /* Note: this inits the reference count to 1, this is considered unreferenced */
+       os_ref_init_raw(&dnp->dn_refcount, &devfs_refgrp);
        dnp->dn_ino = devfs_unique_fileno;
        devfs_unique_fileno++;
 
@@ -627,8 +633,8 @@ dev_add_node(int entrytype, devnode_type_t * typeinfo, devnode_t * proto,
                    typeinfo->Slnk.namelen + 1,
                    M_DEVFSNODE, M_WAITOK);
                if (!dnp->dn_typeinfo.Slnk.name) {
-                       FREE(dnp, M_DEVFSNODE);
-                       return ENOMEM;
+                       error = ENOMEM;
+                       break;
                }
                strlcpy(dnp->dn_typeinfo.Slnk.name, typeinfo->Slnk.name,
                    typeinfo->Slnk.namelen + 1);
@@ -656,12 +662,17 @@ dev_add_node(int entrytype, devnode_type_t * typeinfo, devnode_t * proto,
 
        #endif /* FDESC */
        default:
-               return EINVAL;
+               error = EINVAL;
        }
 
-       *dn_pp = dnp;
-       DEVFS_INCR_NODES();
-       return 0;
+       if (error) {
+               FREE(dnp, M_DEVFSNODE);
+       } else {
+               *dn_pp = dnp;
+               DEVFS_INCR_NODES();
+       }
+
+       return error;
 }
 
 
@@ -698,7 +709,10 @@ devfs_dn_free(devnode_t * dnp)
                }
 
                /* Can only free if there are no references; otherwise, wait for last vnode to be reclaimed */
-               if (dnp->dn_refcount == 0) {
+               os_ref_count_t rc = os_ref_get_count_raw(&dnp->dn_refcount);
+               if (rc == 1) {
+                       /* release final reference from dev_add_node */
+                       (void) os_ref_release_locked_raw(&dnp->dn_refcount, &devfs_refgrp);
                        devnode_free(dnp);
                } else {
                        dnp->dn_lflags |= DN_DELETE;
@@ -1362,20 +1376,22 @@ out:
 void
 devfs_ref_node(devnode_t *dnp)
 {
-       dnp->dn_refcount++;
+       os_ref_retain_locked_raw(&dnp->dn_refcount, &devfs_refgrp);
 }
 
 /*
  * Release a reference on a devnode.  If the devnode is marked for
- * free and the refcount is dropped to zero, do the free.
+ * free and the refcount is dropped to one, do the free.
  */
 void
 devfs_rele_node(devnode_t *dnp)
 {
-       dnp->dn_refcount--;
-       if (dnp->dn_refcount < 0) {
-               panic("devfs_rele_node: devnode with a negative refcount!\n");
-       } else if ((dnp->dn_refcount == 0) && (dnp->dn_lflags & DN_DELETE)) {
+       os_ref_count_t rc = os_ref_release_locked_raw(&dnp->dn_refcount, &devfs_refgrp);
+       if (rc < 1) {
+               panic("devfs_rele_node: devnode without a refcount!\n");
+       } else if ((rc == 1) && (dnp->dn_lflags & DN_DELETE)) {
+               /* release final reference from dev_add_node */
+               (void) os_ref_release_locked_raw(&dnp->dn_refcount, &devfs_refgrp);
                devnode_free(dnp);
        }
 }