mm/vmalloc: respect passed gfp_mask when doing preloading

Allocation functions should comply with the given gfp_mask as much as
possible.  The preallocation code in alloc_vmap_area doesn't follow that
pattern and it is using a hardcoded GFP_KERNEL.  Although this doesn't
really make much difference because vmalloc is not GFP_NOWAIT compliant
in general (e.g.  page table allocations are GFP_KERNEL) there is no
reason to spread that bad habit and it is good to fix the antipattern.

[mhocko@suse.com: rewrite changelog]
Link: http://lkml.kernel.org/r/20191016095438.12391-2-urezki@gmail.comSigned-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Daniel Wagner <dwagner@suse.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -1063,9 +1063,9 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 		return ERR_PTR(-EBUSY);
 
 	might_sleep();
+	gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
 
-	va = kmem_cache_alloc_node(vmap_area_cachep,
-			gfp_mask & GFP_RECLAIM_MASK, node);
+	va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
 	if (unlikely(!va))
 		return ERR_PTR(-ENOMEM);
 
@@ -1073,7 +1073,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	 * Only scan the relevant parts containing pointers to other objects
 	 * to avoid false negatives.
 	 */
-	kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK);
+	kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask);
 
 retry:
 	/*
@@ -1099,7 +1099,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 		 * Just proceed as it is. If needed "overflow" path
 		 * will refill the cache we allocate from.
 		 */
-		pva = kmem_cache_alloc_node(vmap_area_cachep, GFP_KERNEL, node);
+		pva = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
 
 	spin_lock(&vmap_area_lock);