PM: hibernate: Use vmalloc_array() and vcalloc() to improve code

Remove array_size() calls and replace vmalloc() and vzalloc() with
vmalloc_array() and vcalloc() respectively to simplify the code in
save_compressed_image() and load_compressed_image().

vmalloc_array() is also optimized better, resulting in less
instructions being used, and vmalloc_array() handling overhead is
lower [1].

Link: https://lore.kernel.org/lkml/abc66ec5-85a4-47e1-9759-2f60ab111971@vivo.com/ [1]
Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Link: https://patch.msgid.link/20250817083636.53872-1-rongqianfeng@vivo.com
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: qianfengrong

kernel/power/swap.c

@@ -712,7 +712,7 @@ static int save_compressed_image(struct swap_map_handle *handle,
 		goto out_clean;
 	}
 
-	data = vzalloc(array_size(nr_threads, sizeof(*data)));
+	data = vcalloc(nr_threads, sizeof(*data));
 	if (!data) {
 		pr_err("Failed to allocate %s data\n", hib_comp_algo);
 		ret = -ENOMEM;
@@ -1225,14 +1225,14 @@ static int load_compressed_image(struct swap_map_handle *handle,
 	nr_threads = num_online_cpus() - 1;
 	nr_threads = clamp_val(nr_threads, 1, CMP_THREADS);
 
-	page = vmalloc(array_size(CMP_MAX_RD_PAGES, sizeof(*page)));
+	page = vmalloc_array(CMP_MAX_RD_PAGES, sizeof(*page));
 	if (!page) {
 		pr_err("Failed to allocate %s page\n", hib_comp_algo);
 		ret = -ENOMEM;
 		goto out_clean;
 	}
 
-	data = vzalloc(array_size(nr_threads, sizeof(*data)));
+	data = vcalloc(nr_threads, sizeof(*data));
 	if (!data) {
 		pr_err("Failed to allocate %s data\n", hib_comp_algo);
 		ret = -ENOMEM;