CAPI: Sanitize capifs API

Instead of looking up the dentry of an NCCI node again in
capifs_free_ncci pass the pointer via the capifs user.

This patch also reduces the #ifdef mess in capi.c a bit as far as capifs
was causing it.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 54 insertions, 31 deletions

diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 79f9364aded6..dc5ac52986ee 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -42,9 +42,8 @@
 #include <linux/moduleparam.h>
 #include <linux/isdn/capiutil.h>
 #include <linux/isdn/capicmd.h>
-#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
+
 #include "capifs.h"
-#endif
 
 static char *revision = "$Revision: 1.1.2.7 $";
 
@@ -96,6 +95,7 @@ struct capiminor {
         struct list_head list;
         struct capincci  *nccip;
         unsigned int      minor;
+        struct dentry *capifs_dentry;
 
         struct capi20_appl *ap;
         u32              ncci;
@@ -328,9 +328,9 @@ static struct capincci *capincci_alloc(struct capidev *cdev, u32 ncci)
 #ifdef _DEBUG_REFCOUNT
                 printk(KERN_DEBUG "set mp->nccip\n");
 #endif
-#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
-                capifs_new_ncci(mp->minor, MKDEV(capi_ttymajor, mp->minor));
-#endif
+                mp->capifs_dentry =
+                        capifs_new_ncci(mp->minor,
+                                        MKDEV(capi_ttymajor, mp->minor));
         }
 #endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
         for (pp=&cdev->nccis; *pp; pp = &(*pp)->next)
@@ -353,9 +353,7 @@ static void capincci_free(struct capidev *cdev, u32 ncci)
                         *pp = (*pp)->next;
 #ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
                         if ((mp = np->minorp) != NULL) {
-#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
-                                capifs_free_ncci(mp->minor);
-#endif
+                                capifs_free_ncci(mp->capifs_dentry);
                                 if (mp->tty) {
                                         mp->nccip = NULL;
 #ifdef _DEBUG_REFCOUNT
diff --git a/drivers/isdn/capi/capifs.c b/drivers/isdn/capi/capifs.c
index dc68fcb122a0..91aafadd413f 100644
--- a/drivers/isdn/capi/capifs.c
+++ b/drivers/isdn/capi/capifs.c
@@ -141,31 +141,32 @@ static struct file_system_type capifs_fs_type = {
         .kill_sb        = kill_anon_super,
 };
 
-static struct dentry *get_node(int num)
-{
-        char s[10];
-        struct dentry *root = capifs_root;
-        mutex_lock(&root->d_inode->i_mutex);
-        return lookup_one_len(s, root, sprintf(s, "%d", num));
-}
-
-void capifs_new_ncci(unsigned int number, dev_t device)
+struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
 {
         struct dentry *dentry;
         struct inode *inode;
+        char name[10];
+        int namelen;
 
-        dentry = get_node(number);
-        if (IS_ERR(dentry))
+        mutex_lock(&capifs_root->d_inode->i_mutex);
+
+        namelen = sprintf(name, "%d", number);
+        dentry = lookup_one_len(name, capifs_root, namelen);
+        if (IS_ERR(dentry)) {
+                dentry = NULL;
                 goto unlock_out;
+        }
 
         if (dentry->d_inode) {
                 dput(dentry);
+                dentry = NULL;
                 goto unlock_out;
         }
 
         inode = new_inode(capifs_mnt->mnt_sb);
         if (!inode) {
                 dput(dentry);
+                dentry = NULL;
                 goto unlock_out;
         }
 
@@ -177,24 +178,31 @@ void capifs_new_ncci(unsigned int number, dev_t device)
         init_special_inode(inode, S_IFCHR|config.mode, device);
 
         d_instantiate(dentry, inode);
+        dget(dentry);
 
 unlock_out:
         mutex_unlock(&capifs_root->d_inode->i_mutex);
+
+        return dentry;
 }
 
-void capifs_free_ncci(unsigned int number)
+void capifs_free_ncci(struct dentry *dentry)
 {
-        struct dentry *dentry = get_node(number);
-
-        if (!IS_ERR(dentry)) {
-                struct inode *inode = dentry->d_inode;
-                if (inode) {
-                        inode->i_nlink--;
-                        d_delete(dentry);
-                        dput(dentry);
-                }
+        struct inode *inode;
+
+        if (!dentry)
+                return;
+
+        mutex_lock(&capifs_root->d_inode->i_mutex);
+
+        inode = dentry->d_inode;
+        if (inode) {
+                drop_nlink(inode);
+                d_delete(dentry);
                 dput(dentry);
         }
+        dput(dentry);
+
         mutex_unlock(&capifs_root->d_inode->i_mutex);
 }
 
diff --git a/drivers/isdn/capi/capifs.h b/drivers/isdn/capi/capifs.h
index d0bd4c3c430a..e193d1189531 100644
--- a/drivers/isdn/capi/capifs.h
+++ b/drivers/isdn/capi/capifs.h
@@ -7,5 +7,22 @@
  *
  */
 
-void capifs_new_ncci(unsigned int num, dev_t device);
-void capifs_free_ncci(unsigned int num);
+#include <linux/dcache.h>
+
+#if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
+
+struct dentry *capifs_new_ncci(unsigned int num, dev_t device);
+void capifs_free_ncci(struct dentry *dentry);
+
+#else
+
+static inline struct dentry *capifs_new_ncci(unsigned int num, dev_t device)
+{
+        return NULL;
+}
+
+static inline void capifs_free_ncci(struct dentry *dentry)
+{
+}
+
+#endif