mm/slab_common: Improve error handling in kmem_cache_create
Instead of using s == NULL use an errorcode. This allows much more
detailed diagnostics as to what went wrong. As we add more functionality
from the slab allocators to the common kmem_cache_create() function we will
also add more error conditions.
Print the error code during the panic as well as in a warning if the module
can handle failure. The API for kmem_cache_create() currently does not allow
the returning of an error code. Return NULL but log the cause of the problem
in the syslog.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 8cf8b49..fe8dc94 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -98,16 +98,36 @@
unsigned long flags, void (*ctor)(void *))
{
struct kmem_cache *s = NULL;
+ int err = 0;
get_online_cpus();
mutex_lock(&slab_mutex);
- if (kmem_cache_sanity_check(name, size) == 0)
- s = __kmem_cache_create(name, size, align, flags, ctor);
+
+ if (!kmem_cache_sanity_check(name, size) == 0)
+ goto out_locked;
+
+
+ s = __kmem_cache_create(name, size, align, flags, ctor);
+ if (!s)
+ err = -ENOSYS; /* Until __kmem_cache_create returns code */
+
+out_locked:
mutex_unlock(&slab_mutex);
put_online_cpus();
- if (!s && (flags & SLAB_PANIC))
- panic("kmem_cache_create: Failed to create slab '%s'\n", name);
+ if (err) {
+
+ if (flags & SLAB_PANIC)
+ panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
+ name, err);
+ else {
+ printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
+ name, err);
+ dump_stack();
+ }
+
+ return NULL;
+ }
return s;
}