carl9170: Use the bitmap API when applicable

Use 'bitmap_zalloc()' to simplify code, improve the semantic and avoid some
open-coded arithmetic in allocator arguments.

Note, that this 'bitmap_zalloc()' divides by BITS_PER_LONG the amount of
memory allocated.
The 'roundup()' used to computed the number of needed long should have
been a DIV_ROUND_UP.


Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

Use 'bitmap_zero()' to avoid hand writing it.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1fe18fb73f71d855043c40c83865ad539f326478.1638396221.git.christophe.jaillet@wanadoo.fr

drivers/net/wireless/ath/carl9170/main.c

@@ -307,8 +307,7 @@ static void carl9170_zap_queues(struct ar9170 *ar)
 	for (i = 0; i < ar->hw->queues; i++)
 		ar->tx_stats[i].limit = CARL9170_NUM_TX_LIMIT_HARD;
 
-	for (i = 0; i < DIV_ROUND_UP(ar->fw.mem_blocks, BITS_PER_LONG); i++)
-		ar->mem_bitmap[i] = 0;
+	bitmap_zero(ar->mem_bitmap, ar->fw.mem_blocks);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(cvif, &ar->vif_list, list) {
@@ -1968,9 +1967,7 @@ int carl9170_register(struct ar9170 *ar)
 	if (WARN_ON(ar->mem_bitmap))
 		return -EINVAL;
 
-	ar->mem_bitmap = kcalloc(roundup(ar->fw.mem_blocks, BITS_PER_LONG),
-				 sizeof(unsigned long),
-				 GFP_KERNEL);
+	ar->mem_bitmap = bitmap_zalloc(ar->fw.mem_blocks, GFP_KERNEL);
 
 	if (!ar->mem_bitmap)
 		return -ENOMEM;
@@ -2085,7 +2082,7 @@ void carl9170_free(struct ar9170 *ar)
 	kfree_skb(ar->rx_failover);
 	ar->rx_failover = NULL;
 
-	kfree(ar->mem_bitmap);
+	bitmap_free(ar->mem_bitmap);
 	ar->mem_bitmap = NULL;
 
 	kfree(ar->survey);