[PATCH] proc: sysctl: add _proc_do_string helper

The logic in proc_do_string is worth re-using without passing in a
ctl_table structure (say, we want to calculate a pointer and pass that in
instead); pass in the two fields it uses from that structure as explicit
arguments.

Signed-off-by: Sam Vilain <sam.vilain@catalyst.net.nz>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 36 insertions, 29 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ba42694f0453..8b5f4bb8ad2f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1624,32 +1624,14 @@ static ssize_t proc_writesys(struct file * file, const char __user * buf,
         return do_rw_proc(1, file, (char __user *) buf, count, ppos);
 }
 
-/**
- * proc_dostring - read a string sysctl
- * @table: the sysctl table
- * @write: %TRUE if this is a write to the sysctl file
- * @filp: the file structure
- * @buffer: the user buffer
- * @lenp: the size of the user buffer
- * @ppos: file position
- *
- * Reads/writes a string from/to the user buffer. If the kernel
- * buffer provided is not large enough to hold the string, the
- * string is truncated. The copied string is %NULL-terminated.
- * If the string is being read by the user process, it is copied
- * and a newline '\n' is added. It is truncated if the buffer is
- * not large enough.
- *
- * Returns 0 on success.
- */
-int proc_dostring(ctl_table *table, int write, struct file *filp,
-                  void __user *buffer, size_t *lenp, loff_t *ppos)
+int _proc_do_string(void* data, int maxlen, int write, struct file *filp,
+                    void __user *buffer, size_t *lenp, loff_t *ppos)
 {
         size_t len;
         char __user *p;
         char c;
         
-        if (!table->data || !table->maxlen || !*lenp ||
+        if (!data || !maxlen || !*lenp ||
             (*ppos && !write)) {
                 *lenp = 0;
                 return 0;
@@ -1665,20 +1647,20 @@ int proc_dostring(ctl_table *table, int write, struct file *filp,
                                 break;
                         len++;
                 }
-                if (len >= table->maxlen)
-                        len = table->maxlen-1;
-                if(copy_from_user(table->data, buffer, len))
+                if (len >= maxlen)
+                        len = maxlen-1;
+                if(copy_from_user(data, buffer, len))
                         return -EFAULT;
-                ((char *) table->data)[len] = 0;
+                ((char *) data)[len] = 0;
                 *ppos += *lenp;
         } else {
-                len = strlen(table->data);
-                if (len > table->maxlen)
-                        len = table->maxlen;
+                len = strlen(data);
+                if (len > maxlen)
+                        len = maxlen;
                 if (len > *lenp)
                         len = *lenp;
                 if (len)
-                        if(copy_to_user(buffer, table->data, len))
+                        if(copy_to_user(buffer, data, len))
                                 return -EFAULT;
                 if (len < *lenp) {
                         if(put_user('\n', ((char __user *) buffer) + len))
@@ -1691,6 +1673,31 @@ int proc_dostring(ctl_table *table, int write, struct file *filp,
         return 0;
 }
 
+/**
+ * proc_dostring - read a string sysctl
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @filp: the file structure
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes a string from/to the user buffer. If the kernel
+ * buffer provided is not large enough to hold the string, the
+ * string is truncated. The copied string is %NULL-terminated.
+ * If the string is being read by the user process, it is copied
+ * and a newline '\n' is added. It is truncated if the buffer is
+ * not large enough.
+ *
+ * Returns 0 on success.
+ */
+int proc_dostring(ctl_table *table, int write, struct file *filp,
+                  void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        return _proc_do_string(table->data, table->maxlen, write, filp,
+                               buffer, lenp, ppos);
+}
+
 /*
  *      Special case of dostring for the UTS structure. This has locks
  *      to observe. Should this be in kernel/sys.c ????