The patch titled
Subject: mm/slab_common.c: restructure kmem_cache_create() to move debug cache integrity checks into a new function
has been added to the -mm tree. Its filename is
mm-slab_commonc-restructure-kmem_cache_create-to-move-debug-cache-integrity-checks-into-a-new-function.patch
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------------------------------------------------------
From: Shuah Khan <shuah.khan@xxxxxx>
Subject: mm/slab_common.c: restructure kmem_cache_create() to move debug cache integrity checks into a new function
kmem_cache_create() does cache integrity checks when CONFIG_DEBUG_VM is
defined. These checks interspersed with the regular code path has lead to
compile time warnings when compiled without CONFIG_DEBUG_VM defined.
Restructuring the code to move the integrity checks in to a new function
would eliminate the current compile warning problem and also will allow
for future changes to the debug only code to evolve without introducing
new warnings in the regular path. This restructuring work is based on the
discussion in the following thread:
https://lkml.org/lkml/2012/7/13/424
Signed-off-by: Shuah Khan <shuah.khan@xxxxxx>
Acked-by: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab_common.c | 90 ++++++++++++++++++++++++---------------------
1 file changed, 48 insertions(+), 42 deletions(-)
diff -puN mm/slab_common.c~mm-slab_commonc-restructure-kmem_cache_create-to-move-debug-cache-integrity-checks-into-a-new-function mm/slab_common.c
--- a/mm/slab_common.c~mm-slab_commonc-restructure-kmem_cache_create-to-move-debug-cache-integrity-checks-into-a-new-function
+++ a/mm/slab_common.c
@@ -23,6 +23,52 @@ enum slab_state slab_state;
LIST_HEAD(slab_caches);
DEFINE_MUTEX(slab_mutex);
+#ifdef CONFIG_DEBUG_VM
+static int kmem_cache_sanity_check(const char *name, size_t size)
+{
+ struct kmem_cache *s = NULL;
+
+ if (!name || in_interrupt() || size < sizeof(void *) ||
+ size > KMALLOC_MAX_SIZE) {
+ pr_err("kmem_cache_create(%s) integrity check failed\n", name);
+ return -EINVAL;
+ }
+
+ list_for_each_entry(s, &slab_caches, list) {
+ char tmp;
+ int res;
+
+ /*
+ * This happens when the module gets unloaded and doesn't
+ * destroy its slab cache and no-one else reuses the vmalloc
+ * area of the module. Print a warning.
+ */
+ res = probe_kernel_address(s->name, tmp);
+ if (res) {
+ pr_err("Slab cache with size %d has lost its name\n",
+ s->object_size);
+ continue;
+ }
+
+ if (!strcmp(s->name, name)) {
+ pr_err("%s (%s): Cache name already exists.\n",
+ __func__, name);
+ dump_stack();
+ s = NULL;
+ return -EINVAL;
+ }
+ }
+
+ WARN_ON(strchr(name, ' ')); /* It confuses parsers */
+ return 0;
+}
+#else
+static inline int kmem_cache_sanity_check(const char *name, size_t size)
+{
+ return 0;
+}
+#endif
+
/*
* kmem_cache_create - Create a cache.
* @name: A string which is used in /proc/slabinfo to identify this cache.
@@ -53,48 +99,11 @@ struct kmem_cache *kmem_cache_create(con
{
struct kmem_cache *s = NULL;
-#ifdef CONFIG_DEBUG_VM
- if (!name || in_interrupt() || size < sizeof(void *) ||
- size > KMALLOC_MAX_SIZE) {
- printk(KERN_ERR "kmem_cache_create(%s) integrity check"
- " failed\n", name);
- goto out;
- }
-#endif
-
get_online_cpus();
mutex_lock(&slab_mutex);
-#ifdef CONFIG_DEBUG_VM
- list_for_each_entry(s, &slab_caches, list) {
- char tmp;
- int res;
-
- /*
- * This happens when the module gets unloaded and doesn't
- * destroy its slab cache and no-one else reuses the vmalloc
- * area of the module. Print a warning.
- */
- res = probe_kernel_address(s->name, tmp);
- if (res) {
- printk(KERN_ERR
- "Slab cache with size %d has lost its name\n",
- s->object_size);
- continue;
- }
-
- if (!strcmp(s->name, name)) {
- printk(KERN_ERR "kmem_cache_create(%s): Cache name"
- " already exists.\n",
- name);
- dump_stack();
- s = NULL;
- goto oops;
- }
- }
-
- WARN_ON(strchr(name, ' ')); /* It confuses parsers */
-#endif
+ if (kmem_cache_sanity_check(name, size))
+ goto oops;
s = __kmem_cache_create(name, size, align, flags, ctor);
@@ -104,9 +113,6 @@ oops:
mutex_unlock(&slab_mutex);
put_online_cpus();
-#ifdef CONFIG_DEBUG_VM
-out:
-#endif
if (!s && (flags & SLAB_PANIC))
panic("kmem_cache_create: Failed to create slab '%s'\n", name);
_
Patches currently in -mm which might be from shuah.khan@xxxxxx are
mm-slab_commonc-restructure-kmem_cache_create-to-move-debug-cache-integrity-checks-into-a-new-function.patch
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