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.
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
Index: linux-2.6/mm/slab_common.c
===================================================================
--- linux-2.6.orig/mm/slab_common.c 2012-08-02 14:00:41.547674458 -0500
+++ linux-2.6/mm/slab_common.c 2012-08-02 14:21:07.061676525 -0500
@@ -51,13 +51,13 @@
struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align,
unsigned long flags, void (*ctor)(void *))
{
- struct kmem_cache *s = NULL;
+ struct kmem_cache *s;
+ int err = 0;
#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);
+ err = -EINVAL;
goto out;
}
#endif
@@ -84,11 +84,7 @@
}
if (!strcmp(s->name, name)) {
- printk(KERN_ERR "kmem_cache_create(%s): Cache name"
- " already exists.\n",
- name);
- dump_stack();
- s = NULL;
+ err = -EEXIST;
goto out_locked;
}
}
@@ -97,6 +93,8 @@
#endif
s = __kmem_cache_create(name, size, align, flags, ctor);
+ if (!s)
+ err = -ENOSYS; /* Until __kmem_cache_create returns code */
#ifdef CONFIG_DEBUG_VM
out_locked:
@@ -107,8 +105,19 @@
#ifdef CONFIG_DEBUG_VM
out:
#endif
- 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;
}
--
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