slub: make ->remote_node_defrag_ratio unsigned int

->remote_node_defrag_ratio is in range 0..1000.

This also adds a check and modifies the behavior to return an error
code.  Before this patch invalid values were ignored.

Link: http://lkml.kernel.org/r/20180305200730.15812-9-adobriyan@gmail.com
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 8ad99c4..f654808 100644 (file)
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -124,7 +124,7 @@ struct kmem_cache {
        /*
         * Defragmentation by allocating from a remote node.
         */
-       int remote_node_defrag_ratio;
+       unsigned int remote_node_defrag_ratio;
 #endif
 
 #ifdef CONFIG_SLAB_FREELIST_RANDOM

diff --git a/mm/slub.c b/mm/slub.c
index 495c785..97dd2db 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5289,21 +5289,22 @@ SLAB_ATTR(shrink);
 #ifdef CONFIG_NUMA
 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
 {
-       return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
+       return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10);
 }
 
 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
                                const char *buf, size_t length)
 {
-       unsigned long ratio;
+       unsigned int ratio;
        int err;
 
-       err = kstrtoul(buf, 10, &ratio);
+       err = kstrtouint(buf, 10, &ratio);
        if (err)
                return err;
+       if (ratio > 100)
+               return -ERANGE;
 
-       if (ratio <= 100)
-               s->remote_node_defrag_ratio = ratio * 10;
+       s->remote_node_defrag_ratio = ratio * 10;
 
        return length;
 }