kernfs: convert node name allocation to kstrdup_const

sysfs frequently performs duplication of strings located in read-only
memory section.  Replacing kstrdup by kstrdup_const allows to avoid such
operations.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Greg KH <greg@kroah.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 2d881b381d2b787bbb2ff40b151e7496c0abafae..35e40879860aebc4491082ca3dbc0bad6ef70727 100644 (file)
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -412,7 +412,7 @@ void kernfs_put(struct kernfs_node *kn)
        if (kernfs_type(kn) == KERNFS_LINK)
                kernfs_put(kn->symlink.target_kn);
        if (!(kn->flags & KERNFS_STATIC_NAME))
-               kfree(kn->name);
+               kfree_const(kn->name);
        if (kn->iattr) {
                if (kn->iattr->ia_secdata)
                        security_release_secctx(kn->iattr->ia_secdata,
@@ -506,12 +506,12 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
                                             const char *name, umode_t mode,
                                             unsigned flags)
 {
-       char *dup_name = NULL;
+       const char *dup_name = NULL;
        struct kernfs_node *kn;
        int ret;
 
        if (!(flags & KERNFS_STATIC_NAME)) {
-               name = dup_name = kstrdup(name, GFP_KERNEL);
+               name = dup_name = kstrdup_const(name, GFP_KERNEL);
                if (!name)
                        return NULL;
        }
@@ -538,7 +538,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
  err_out2:
        kmem_cache_free(kernfs_node_cache, kn);
  err_out1:
-       kfree(dup_name);
+       kfree_const(dup_name);
        return NULL;
 }
 
@@ -1264,7 +1264,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
        /* rename kernfs_node */
        if (strcmp(kn->name, new_name) != 0) {
                error = -ENOMEM;
-               new_name = kstrdup(new_name, GFP_KERNEL);
+               new_name = kstrdup_const(new_name, GFP_KERNEL);
                if (!new_name)
                        goto out;
        } else {
@@ -1297,7 +1297,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
        kernfs_link_sibling(kn);
 
        kernfs_put(old_parent);
-       kfree(old_name);
+       kfree_const(old_name);
 
        error = 0;
  out: