[PATCH] implement ksize()

[Christoph Hellwig]

It's used to find out the effective allocation size of objects allocated
by kmalloc().  This is needed by the uClinux ports in many places but
seems also usefull for mmu-using ports.

--- 1.13/include/linux/slab.h	Wed Sep 25 20:41:05 2002
+++ edited/include/linux/slab.h	Sun Nov  3 03:08:32 2002
@@ -60,6 +60,7 @@
 
 extern void *kmalloc(size_t, int);
 extern void kfree(const void *);
+extern unsigned int ksize(const void *);
 
 extern int FASTCALL(kmem_cache_reap(int));
 
--- 1.156/kernel/ksyms.c	Thu Oct 31 10:28:34 2002
+++ edited/kernel/ksyms.c	Sun Nov  3 03:09:00 2002
@@ -104,6 +104,7 @@
 EXPORT_SYMBOL(remove_shrinker);
 EXPORT_SYMBOL(kmalloc);
 EXPORT_SYMBOL(kfree);
+EXPORT_SYMBOL(ksize);
 EXPORT_SYMBOL(vfree);
 EXPORT_SYMBOL(__vmalloc);
 EXPORT_SYMBOL(vmalloc);
--- 1.46/mm/slab.c	Fri Nov  1 16:34:38 2002
+++ edited/mm/slab.c	Sun Nov  3 13:18:29 2002
@@ -1871,6 +1871,22 @@
 	return cachep->objsize;
 }
 
+unsigned int ksize(const void *objp)
+{
+	kmem_cache_t *c;
+	unsigned long flags;
+	unsigned int size = 0;
+
+	if (objp) {
+		local_irq_save(flags);
+		c = GET_PAGE_CACHE(virt_to_page(objp));
+		size = kmem_cache_size(c);
+		local_irq_restore(flags);
+	}
+
+	return size;
+}
+
 kmem_cache_t * kmem_find_general_cachep (size_t size, int gfpflags)
 {
 	struct cache_sizes *csizep = malloc_sizes;