[RFC PATCH v3 13/59] getname_flags() massage, part 2

[Al Viro]

Take the "long name" case into a helper (getname_long()). In
case of failure have the caller deal with freeing the original
struct filename.

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
---
 fs/namei.c | 56 ++++++++++++++++++++++++++++--------------------------
 1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index ea7efbddc7f4..471e4db2dbdb 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -131,6 +131,32 @@ static inline void initname(struct filename *name)
        atomic_set(&name->refcnt, 1);
 }
 
+static struct filename *getname_long(struct filename *old,
+                                    const char __user *filename)
+{
+       int len;
+       /*
+        * size is chosen that way we to guarantee that
+        * p->iname[0] is within the same object and that
+        * p->name can't be equal to p->iname, no matter what.
+        */
+       const size_t size = offsetof(struct filename, iname[1]);
+       struct filename *p __free(kfree) = kzalloc(size, GFP_KERNEL);
+       if (unlikely(!p))
+               return ERR_PTR(-ENOMEM);
+
+       memmove(old, &old->iname, EMBEDDED_NAME_MAX);
+       p->name = (char *)old;
+       len = strncpy_from_user((char *)old + EMBEDDED_NAME_MAX,
+                               filename + EMBEDDED_NAME_MAX,
+                               PATH_MAX - EMBEDDED_NAME_MAX);
+       if (unlikely(len < 0))
+               return ERR_PTR(len);
+       if (unlikely(len == PATH_MAX - EMBEDDED_NAME_MAX))
+               return ERR_PTR(-ENAMETOOLONG);
+       return no_free_ptr(p);
+}
+
 struct filename *
 getname_flags(const char __user *filename, int flags)
 {
@@ -173,34 +199,10 @@ getname_flags(const char __user *filename, int flags)
         * userland.
         */
        if (unlikely(len == EMBEDDED_NAME_MAX)) {
-               const size_t size = offsetof(struct filename, iname[1]);
-               struct filename *p;
-
-               /*
-                * size is chosen that way we to guarantee that
-                * result->iname[0] is within the same object and that
-                * kname can't be equal to result->iname, no matter what.
-                */
-               p = kzalloc(size, GFP_KERNEL);
-               if (unlikely(!p)) {
-                       __putname(result);
-                       return ERR_PTR(-ENOMEM);
-               }
-               memmove(result, &result->iname, EMBEDDED_NAME_MAX);
-               kname = (char *)result;
-               p->name = kname;
-               len = strncpy_from_user(kname + EMBEDDED_NAME_MAX,
-                                       filename + EMBEDDED_NAME_MAX,
-                                       PATH_MAX - EMBEDDED_NAME_MAX);
-               if (unlikely(len < 0)) {
-                       kfree(p);
-                       __putname(result);
-                       return ERR_PTR(len);
-               }
-               if (unlikely(len == PATH_MAX - EMBEDDED_NAME_MAX)) {
-                       kfree(p);
+               struct filename *p = getname_long(result, filename);
+               if (IS_ERR(p)) {
                        __putname(result);
-                       return ERR_PTR(-ENAMETOOLONG);
+                       return p;
                }
                result = p;
        }
-- 
2.47.3