[PATCH][2.4][ATM] cleanup atm_dev_ioctl a bit (from mitch@sfgoth.com)

[chas williams <chas@xxxxxxxxxxxxxxxx>]

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#                  ChangeSet    1.1131  -> 1.1132 
#        net/atm/resources.c    1.7     -> 1.8    
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/09/14      chas@xxxxxxxxxxxxxxxxxxxxxx     1.1132
# resources.c:
#   [ATM]: cleanup atm_dev_ioctl a bit (from mitch@xxxxxxxxxx)
# --------------------------------------------
#
diff -Nru a/net/atm/resources.c b/net/atm/resources.c
--- a/net/atm/resources.c       Mon Sep 15 16:17:02 2003
+++ b/net/atm/resources.c       Mon Sep 15 16:17:02 2003
@@ -214,42 +214,42 @@
 int atm_dev_ioctl(unsigned int cmd, unsigned long arg)
 {
        void *buf;
-       int error, len, number, size = 0;
+       int error = 0, len, number, size = 0;
        struct atm_dev *dev;
-       struct list_head *p;
-       int *tmp_buf, *tmp_p;
 
-       switch (cmd) {
-               case ATM_GETNAMES:
-                       if (get_user(buf, &((struct atm_iobuf *) arg)->buffer))
-                               return -EFAULT;
-                       if (get_user(len, &((struct atm_iobuf *) arg)->length))
-                               return -EFAULT;
-                       spin_lock(&atm_dev_lock);
-                       list_for_each(p, &atm_devs)
-                               size += sizeof(int);
-                       if (size > len) {
-                               spin_unlock(&atm_dev_lock);
-                               return -E2BIG;
-                       }
-                       tmp_buf = kmalloc(size, GFP_ATOMIC);
-                       if (!tmp_buf) {
-                               spin_unlock(&atm_dev_lock);
-                               return -ENOMEM;
-                       }
-                       tmp_p = tmp_buf;
-                       list_for_each(p, &atm_devs) {
-                               dev = list_entry(p, struct atm_dev, dev_list);
-                               *tmp_p++ = dev->number;
-                       }
+       if (cmd == ATM_GETNAMES) {
+               int *tmp_buf, *tmp_bufp;
+               struct list_head *p;
+               /*
+                * ATM_GETNAMES is a special case: it doesn't require a
+                * device number argument
+                */
+               if (get_user(buf, &((struct atm_iobuf *) arg)->buffer))
+                       return -EFAULT;
+               if (get_user(len, &((struct atm_iobuf *) arg)->length))
+                       return -EFAULT;
+               spin_lock(&atm_dev_lock);
+               list_for_each(p, &atm_devs)
+                       size += sizeof(int);
+               if (size > len) {
                        spin_unlock(&atm_dev_lock);
-                       error = ((copy_to_user(buf, tmp_buf, size)) ||
-                                       put_user(size, &((struct atm_iobuf *) 
arg)->length))
-                                               ? -EFAULT : 0;
-                       kfree(tmp_buf);
-                       return error;
-               default:
-                       break;
+                       return -E2BIG;
+               }
+               tmp_buf = tmp_bufp = kmalloc(size, GFP_ATOMIC);
+               if (!tmp_buf) {
+                       spin_unlock(&atm_dev_lock);
+                       return -ENOMEM;
+               }
+               list_for_each(p, &atm_devs) {
+                       dev = list_entry(p, struct atm_dev, dev_list);
+                       *tmp_bufp++ = dev->number;
+               }
+               spin_unlock(&atm_dev_lock);
+               error = (copy_to_user(buf, tmp_buf, size) ||
+                               put_user(size, &((struct atm_iobuf *) 
arg)->length))
+                                       ? -EFAULT : 0;
+               kfree(tmp_buf);
+               return error;
        }
 
        if (get_user(buf, &((struct atmif_sioc *) arg)->arg))
@@ -361,11 +361,8 @@
                        if (error < 0)
                                goto done;
                        size = error;
-                       /* may return 0, but later on size == 0 means "don't
-                          write the length" */
-                       error = put_user(size, &((struct atmif_sioc *) 
arg)->length)
-                               ? -EFAULT : 0;
-                       goto done;
+                       /* write back size even if it's zero */
+                       goto write_size;
                case ATM_SETLOOP:
                        if (__ATM_LM_XTRMT((int) (long) buf) &&
                            __ATM_LM_XTLOC((int) (long) buf) >
@@ -396,11 +393,12 @@
                        }
        }
        
-       if (size)
-               error = put_user(size, &((struct atmif_sioc *) arg)->length)
-                       ? -EFAULT : 0;
-       else
-               error = 0;
+       if (size) {
+write_size:
+               error = put_user(size,
+                         &((struct atmif_sioc *) arg)->length)
+                         ? -EFAULT : 0;
+       }
 done:
        atm_dev_release(dev);
        return error;