mm/vmalloc: repair warn_alloc()s in __vmalloc_area_node()

Commit f255935b ("mm: cleanup the gfp_mask handling in
__vmalloc_area_node") added __GFP_NOWARN to gfp_mask unconditionally
however it disabled all output inside warn_alloc() call.  This patch
saves original gfp_mask and provides it to all warn_alloc() calls.

Link: https://lkml.kernel.org/r/f4f3187b-9684-e426-565d-827c2a9bbb0e@virtuozzo.com
Fixes: f255935b ("mm: cleanup the gfp_mask handling in __vmalloc_area_node")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -2887,6 +2887,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 				 int node)
 {
 	const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
+	const gfp_t orig_gfp_mask = gfp_mask;
 	unsigned long addr = (unsigned long)area->addr;
 	unsigned long size = get_vm_area_size(area);
 	unsigned long array_size;
@@ -2907,7 +2908,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	}
 
 	if (!area->pages) {
-		warn_alloc(gfp_mask, NULL,
+		warn_alloc(orig_gfp_mask, NULL,
 			"vmalloc error: size %lu, failed to allocated page array size %lu",
 			nr_small_pages * PAGE_SIZE, array_size);
 		free_vm_area(area);
@@ -2927,7 +2928,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	 * allocation request, free them via __vfree() if any.
 	 */
 	if (area->nr_pages != nr_small_pages) {
-		warn_alloc(gfp_mask, NULL,
+		warn_alloc(orig_gfp_mask, NULL,
 			"vmalloc error: size %lu, page order %u, failed to allocate pages",
 			area->nr_pages * PAGE_SIZE, page_order);
 		goto fail;
@@ -2935,7 +2936,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 
 	if (vmap_pages_range(addr, addr + size, prot, area->pages,
 			page_shift) < 0) {
-		warn_alloc(gfp_mask, NULL,
+		warn_alloc(orig_gfp_mask, NULL,
 			"vmalloc error: size %lu, failed to map pages",
 			area->nr_pages * PAGE_SIZE);
 		goto fail;