sysctl: Reduce dput(child) calls in proc_sys_fill_cache()

Replace two dput(child) calls with one that occurs immediately before
the IS_ERR evaluation. This transformation can be performed because
dput() gets called regardless of the value returned by IS_ERR(res).

This issue was transformed by using a script for the
semantic patch language like the following.
<SmPL>
@extended_adjustment@
expression e, f != { mutex_unlock }, x, y;
@@
+f(e);
 if (...)
 {
 <+... when != \( e = x \| y(..., &e, ...) \)
-   f(e);
 ...+>
 }
-f(e);
</SmPL>

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Joel Granados <joel.granados@kernel.org>

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index fac5660..27a283d 100644 (file)
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -704,11 +704,11 @@ static bool proc_sys_fill_cache(struct file *file,
                        res = d_splice_alias(inode, child);
                        d_lookup_done(child);
                        if (unlikely(res)) {
-                               if (IS_ERR(res)) {
-                                       dput(child);
-                                       return false;
-                               }
                                dput(child);
+
+                               if (IS_ERR(res))
+                                       return false;
+
                                child = res;
                        }
                }