powerpc/eeh: Use slab to allocate eeh devices

The EEH initialization functions have been postponed until slab/slub
are ready. So we use slab/slub to allocate the memory chunks for newly
creatd EEH devices. That would save lots of memory.

The patch also does cleanup to replace "kmalloc" with "kzalloc" so
that we needn't clear the allocated memory chunk explicitly.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/eeh_cache.c

@@ -151,7 +151,7 @@ pci_addr_cache_insert(struct pci_dev *dev, unsigned long alo,
 			return piar;
 		}
 	}
-	piar = kmalloc(sizeof(struct pci_io_addr_range), GFP_ATOMIC);
+	piar = kzalloc(sizeof(struct pci_io_addr_range), GFP_ATOMIC);
 	if (!piar)
 		return NULL;
 

arch/powerpc/platforms/pseries/eeh_dev.c

@@ -55,7 +55,7 @@ void * __devinit eeh_dev_init(struct device_node *dn, void *data)
 	struct eeh_dev *edev;
 
 	/* Allocate EEH device */
-	edev = zalloc_maybe_bootmem(sizeof(*edev), GFP_KERNEL);
+	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
 	if (!edev) {
 		pr_warning("%s: out of memory\n", __func__);
 		return NULL;

arch/powerpc/platforms/pseries/eeh_event.c

@@ -139,7 +139,7 @@ int eeh_send_failure_event(struct eeh_dev *edev)
 		printk(KERN_ERR "EEH: PCI location = %s\n", location);
 		return 1;
 	}
-	event = kmalloc(sizeof(*event), GFP_ATOMIC);
+	event = kzalloc(sizeof(*event), GFP_ATOMIC);
 	if (event == NULL) {
 		printk(KERN_ERR "EEH: out of memory, event not handled\n");
 		return 1;