usbmon: Add class for binary interface

Add a class which allows for an easier integration with udev.

This code was originally written by Paolo Abeni, and arrived to my tree
as a part of big patch to add binary API on December 18. As I understand,
Paolo always meant the class to be a part of the whole thing. This is his
udev rule to go along with the patch:

KERNEL=="usbmon[0-9]*", NAME="usbmon%n", MODE="0440",OWNER="root",GROUP="bin"

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index ec0cc51e39ac..982b773d71e6 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -655,20 +655,24 @@ static const struct file_operations mon_fops_text_u = {
         .release =      mon_text_release,
 };
 
-int mon_text_add(struct mon_bus *mbus, int busnum)
+int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus)
 {
         struct dentry *d;
         enum { NAMESZ = 10 };
         char name[NAMESZ];
+        int busnum = ubus? ubus->busnum: 0;
         int rc;
 
-        rc = snprintf(name, NAMESZ, "%dt", busnum);
-        if (rc <= 0 || rc >= NAMESZ)
-                goto err_print_t;
-        d = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_text_t);
-        if (d == NULL)
-                goto err_create_t;
-        mbus->dent_t = d;
+        if (ubus != NULL) {
+                rc = snprintf(name, NAMESZ, "%dt", busnum);
+                if (rc <= 0 || rc >= NAMESZ)
+                        goto err_print_t;
+                d = debugfs_create_file(name, 0600, mon_dir, mbus,
+                                                             &mon_fops_text_t);
+                if (d == NULL)
+                        goto err_create_t;
+                mbus->dent_t = d;
+        }
 
         rc = snprintf(name, NAMESZ, "%du", busnum);
         if (rc <= 0 || rc >= NAMESZ)
@@ -694,8 +698,10 @@ err_print_s:
         mbus->dent_u = NULL;
 err_create_u:
 err_print_u:
-        debugfs_remove(mbus->dent_t);
-        mbus->dent_t = NULL;
+        if (ubus != NULL) {
+                debugfs_remove(mbus->dent_t);
+                mbus->dent_t = NULL;
+        }
 err_create_t:
 err_print_t:
         return 0;
@@ -704,7 +710,8 @@ err_print_t:
 void mon_text_del(struct mon_bus *mbus)
 {
         debugfs_remove(mbus->dent_u);
-        debugfs_remove(mbus->dent_t);
+        if (mbus->dent_t != NULL)
+                debugfs_remove(mbus->dent_t);
         debugfs_remove(mbus->dent_s);
 }