memstick/ms_block: Fix some incorrect memory allocation

Some functions of the bitmap API take advantage of the fact that a bitmap
is an array of long.

So, to make sure this assertion is correct, allocate bitmaps with
bitmap_zalloc() instead of kzalloc()+hand-computed number of bytes.

While at it, also use bitmap_free() instead of kfree() to keep the
semantic.

Fixes: 0ab3049 ("memstick: add support for legacy memorysticks")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/dbf633c48c24ae6d95f852557e8d8b3bbdef65fe.1656155715.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: tititiou36

drivers/memstick/core/ms_block.c

@@ -1341,17 +1341,17 @@ static int msb_ftl_initialize(struct msb_data *msb)
 	msb->zone_count = msb->block_count / MS_BLOCKS_IN_ZONE;
 	msb->logical_block_count = msb->zone_count * 496 - 2;
 
-	msb->used_blocks_bitmap = kzalloc(msb->block_count / 8, GFP_KERNEL);
-	msb->erased_blocks_bitmap = kzalloc(msb->block_count / 8, GFP_KERNEL);
+	msb->used_blocks_bitmap = bitmap_zalloc(msb->block_count, GFP_KERNEL);
+	msb->erased_blocks_bitmap = bitmap_zalloc(msb->block_count, GFP_KERNEL);
 	msb->lba_to_pba_table =
 		kmalloc_array(msb->logical_block_count, sizeof(u16),
 			      GFP_KERNEL);
 
 	if (!msb->used_blocks_bitmap || !msb->lba_to_pba_table ||
 						!msb->erased_blocks_bitmap) {
-		kfree(msb->used_blocks_bitmap);
+		bitmap_free(msb->used_blocks_bitmap);
+		bitmap_free(msb->erased_blocks_bitmap);
 		kfree(msb->lba_to_pba_table);
-		kfree(msb->erased_blocks_bitmap);
 		return -ENOMEM;
 	}
 
@@ -1946,7 +1946,7 @@ static DEFINE_MUTEX(msb_disk_lock); /* protects against races in open/release */
 static void msb_data_clear(struct msb_data *msb)
 {
 	kfree(msb->boot_page);
-	kfree(msb->used_blocks_bitmap);
+	bitmap_free(msb->used_blocks_bitmap);
 	kfree(msb->lba_to_pba_table);
 	kfree(msb->cache);
 	msb->card = NULL;