From 6040f650c56862a4ac40b00c37ef6ab1ddfcebb5 Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Fri, 6 Sep 2024 12:45:44 +0900
Subject: [PATCH] zsmalloc: use unique zsmalloc caches names

Each zsmalloc pool maintains several named kmem-caches for zs_handle-s and
zspage-s.  On a system with multiple zsmalloc pools and CONFIG_DEBUG_VM
this triggers kmem_cache_sanity_check():

  kmem_cache of name 'zspage' already exists
  WARNING: at mm/slab_common.c:108 do_kmem_cache_create_usercopy+0xb5/0x310
  ...

  kmem_cache of name 'zs_handle' already exists
  WARNING: at mm/slab_common.c:108 do_kmem_cache_create_usercopy+0xb5/0x310
  ...

We provide zram device name when init its zsmalloc pool, so we can use
that same name for zsmalloc caches and, hence, create unique names that
can easily be linked to zram device that has created them.

So instead of having this

cat /proc/slabinfo
slabinfo - version: 2.1
zspage                46     46    ...
zs_handle            128    128    ...
zspage             34270  34270    ...
zs_handle          34816  34816    ...
zspage                 0      0    ...
zs_handle              0      0    ...

We now have this

cat /proc/slabinfo
slabinfo - version: 2.1
zspage-zram2          46     46    ...
zs_handle-zram2      128    128    ...
zspage-zram0       34270  34270    ...
zs_handle-zram0    34816  34816    ...
zspage-zram1           0      0    ...
zs_handle-zram1        0      0    ...

Link: https://lkml.kernel.org/r/20240906035103.2435557-1-senozhatsky@chromium.org
Fixes: 2e40e163a25a ("zsmalloc: decouple handle and object")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/zsmalloc.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 2d3163e4da96..b572aa84823c 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -54,6 +54,7 @@
 #include <linux/vmalloc.h>
 #include <linux/preempt.h>
 #include <linux/spinlock.h>
+#include <linux/sprintf.h>
 #include <linux/shrinker.h>
 #include <linux/types.h>
 #include <linux/debugfs.h>
@@ -293,17 +294,27 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
 
 static int create_cache(struct zs_pool *pool)
 {
-	pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
-					0, 0, NULL);
-	if (!pool->handle_cachep)
-		return 1;
+	char *name;
 
-	pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage),
-					0, 0, NULL);
+	name = kasprintf(GFP_KERNEL, "zs_handle-%s", pool->name);
+	if (!name)
+		return -ENOMEM;
+	pool->handle_cachep = kmem_cache_create(name, ZS_HANDLE_SIZE,
+						0, 0, NULL);
+	kfree(name);
+	if (!pool->handle_cachep)
+		return -EINVAL;
+
+	name = kasprintf(GFP_KERNEL, "zspage-%s", pool->name);
+	if (!name)
+		return -ENOMEM;
+	pool->zspage_cachep = kmem_cache_create(name, sizeof(struct zspage),
+						0, 0, NULL);
+	kfree(name);
 	if (!pool->zspage_cachep) {
 		kmem_cache_destroy(pool->handle_cachep);
 		pool->handle_cachep = NULL;
-		return 1;
+		return -EINVAL;
 	}
 
 	return 0;