slub: make ->object_size unsigned int

Linux doesn't support negative length objects.

Link: http://lkml.kernel.org/r/20180305200730.15812-17-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>

include/linux/slub_def.h

@@ -85,7 +85,7 @@ struct kmem_cache {
 	slab_flags_t flags;
 	unsigned long min_partial;
 	int size;		/* The size of an object including meta data */
-	int object_size;	/* The size of an object without meta data */
+	unsigned int object_size;/* The size of an object without meta data */
 	unsigned int offset;	/* Free pointer offset. */
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 	/* Number of per cpu partial objects to keep around */

mm/slab_common.c

@@ -103,7 +103,7 @@ static int kmem_cache_sanity_check(const char *name, unsigned int size)
 		 */
 		res = probe_kernel_address(s->name, tmp);
 		if (res) {
-			pr_err("Slab cache with size %d has lost its name\n",
+			pr_err("Slab cache with size %u has lost its name\n",
 			       s->object_size);
 			continue;
 		}

mm/slub.c

@@ -681,7 +681,7 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 		print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
 
 	print_section(KERN_ERR, "Object ", p,
-		      min_t(unsigned long, s->object_size, PAGE_SIZE));
+		      min_t(unsigned int, s->object_size, PAGE_SIZE));
 	if (s->flags & SLAB_RED_ZONE)
 		print_section(KERN_ERR, "Redzone ", p + s->object_size,
 			s->inuse - s->object_size);
@@ -2399,7 +2399,7 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
 
 	pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
 		nid, gfpflags, &gfpflags);
-	pr_warn("  cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
+	pr_warn("  cache: %s, object size: %u, buffer size: %d, default order: %d, min order: %d\n",
 		s->name, s->object_size, s->size, oo_order(s->oo),
 		oo_order(s->min));
 
@@ -4255,7 +4255,7 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 		 * Adjust the object sizes so that we clear
 		 * the complete object on kzalloc.
 		 */
-		s->object_size = max(s->object_size, (int)size);
+		s->object_size = max(s->object_size, size);
 		s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
 
 		for_each_memcg_cache(c, s) {
@@ -4901,7 +4901,7 @@ SLAB_ATTR_RO(align);
 
 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
 {
-	return sprintf(buf, "%d\n", s->object_size);
+	return sprintf(buf, "%u\n", s->object_size);
 }
 SLAB_ATTR_RO(object_size);