IB/ehca: Fall back to vmalloc() for big allocations

In case of large queue pairs there is the possibillity of allocation
failures due to memory fragmentation when using kmalloc().  To ensure
the memory is allocated even if kmalloc() can not find chunks which
are big enough, we fall back to allocating the memory with vmalloc().
Signed-off-by: Stefan Roscher <stefan.roscher@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ehca/ipz_pt_fn.c

@@ -221,10 +221,13 @@ int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue,
 
 	/* allocate queue page pointers */
 	queue->queue_pages = kmalloc(nr_of_pages * sizeof(void *), GFP_KERNEL);
+	if (!queue->queue_pages) {
+		queue->queue_pages = vmalloc(nr_of_pages * sizeof(void *));
 		if (!queue->queue_pages) {
 			ehca_gen_err("Couldn't allocate queue page list");
 			return 0;
 		}
+	}
 	memset(queue->queue_pages, 0, nr_of_pages * sizeof(void *));
 
 	/* allocate actual queue pages */
@@ -240,6 +243,9 @@ int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue,
 ipz_queue_ctor_exit0:
 	ehca_gen_err("Couldn't alloc pages queue=%p "
 		 "nr_of_pages=%x",  queue, nr_of_pages);
+	if (is_vmalloc_addr(queue->queue_pages))
+		vfree(queue->queue_pages);
+	else
 		kfree(queue->queue_pages);
 
 	return 0;
@@ -262,6 +268,9 @@ int ipz_queue_dtor(struct ehca_pd *pd, struct ipz_queue *queue)
 			free_page((unsigned long)queue->queue_pages[i]);
 	}
 
+	if (is_vmalloc_addr(queue->queue_pages))
+		vfree(queue->queue_pages);
+	else
 		kfree(queue->queue_pages);
 
 	return 1;