mm/slab: Fix /proc/slabinfo unwriteable for slab

Slab have some tunables like limit, batchcount, and sharedfactor can be
tuned through function slabinfo_write. Commit (b7454ad3: mm/sl[au]b: Move
slabinfo processing to slab_common.c) uncorrectly change /proc/slabinfo
unwriteable for slab, this patch fix it by revert to original mode.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 68518eb67229..13ae037c71d4 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -495,6 +495,13 @@ void __init create_kmalloc_caches(unsigned long flags)
 
 
 #ifdef CONFIG_SLABINFO
+
+#ifdef CONFIG_SLAB
+#define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR)
+#else
+#define SLABINFO_RIGHTS S_IRUSR
+#endif
+
 void print_slabinfo_header(struct seq_file *m)
 {
         /*
@@ -631,7 +638,8 @@ static const struct file_operations proc_slabinfo_operations = {
 
 static int __init slab_proc_init(void)
 {
-        proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
+        proc_create("slabinfo", SLABINFO_RIGHTS, NULL,
+                                                &proc_slabinfo_operations);
         return 0;
 }
 module_init(slab_proc_init);