[PATCH v2] staging: rtl8723bs: simplify rtw_spt_band_alloc

[Serhat Kumral <serhatkumral1@gmail.com>]

The function only supports NL80211_BAND_2GHZ and falls through to
exit for any other band. Replace the n_channels and n_bitrates local
variables with the compile-time constants RTW_2G_CHANNELS_NUM and
RTW_G_RATES_NUM directly.

Use simple addition in kzalloc() instead of chained size_add() calls,
since the sizes are derived from compile-time constants and cannot
overflow. Replace the intermediate alloc_sz variable accordingly.

Remove the redundant second band check before the init calls, as
the early exit at the top of the function guarantees that only the
2GHz case can reach that point.

No functional change intended.

Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>

Signed-off-by: Serhat Kumral <serhatkumral1@gmail.com>
---
 .../staging/rtl8723bs/os_dep/ioctl_cfg80211.c | 31 +++++++------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
index 1484336d7..dfc44ebb7 100644
--- a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
@@ -110,33 +110,26 @@ static struct ieee80211_supported_band *rtw_spt_band_alloc(
 	)
 {
 	struct ieee80211_supported_band *spt_band = NULL;
-	int n_channels, n_bitrates;
-	size_t alloc_sz;
+	size_t channels_sz, bitrate_size;
 
-	if (band == NL80211_BAND_2GHZ) {
-		n_channels = RTW_2G_CHANNELS_NUM;
-		n_bitrates = RTW_G_RATES_NUM;
-	} else {
+	if (band != NL80211_BAND_2GHZ)
 		goto exit;
-	}
 
-	alloc_sz = sizeof(*spt_band);
-	alloc_sz = size_add(alloc_sz, array_size(n_channels, sizeof(struct ieee80211_channel)));
-	alloc_sz = size_add(alloc_sz, array_size(n_bitrates, sizeof(struct ieee80211_rate)));
-	spt_band = kzalloc(alloc_sz, GFP_KERNEL);
+	channels_sz = array_size(RTW_2G_CHANNELS_NUM, sizeof(struct ieee80211_channel));
+	bitrate_size = array_size(RTW_G_RATES_NUM, sizeof(struct ieee80211_rate));
+
+	spt_band = kzalloc(sizeof(*spt_band) + channels_sz + bitrate_size, GFP_KERNEL);
 	if (!spt_band)
 		goto exit;
 
-	spt_band->channels = (struct ieee80211_channel *)(((u8 *)spt_band) + sizeof(struct ieee80211_supported_band));
-	spt_band->bitrates = (struct ieee80211_rate *)(((u8 *)spt_band->channels) + sizeof(struct ieee80211_channel) * n_channels);
+	spt_band->channels = (void *)spt_band + sizeof(*spt_band);
+	spt_band->bitrates = (void *)spt_band + sizeof(*spt_band) + channels_sz;
 	spt_band->band = band;
-	spt_band->n_channels = n_channels;
-	spt_band->n_bitrates = n_bitrates;
+	spt_band->n_channels = RTW_2G_CHANNELS_NUM;
+	spt_band->n_bitrates = RTW_G_RATES_NUM;
 
-	if (band == NL80211_BAND_2GHZ) {
-		rtw_2g_channels_init(spt_band->channels);
-		rtw_2g_rates_init(spt_band->bitrates);
-	}
+	rtw_2g_channels_init(spt_band->channels);
+	rtw_2g_rates_init(spt_band->bitrates);
 
 	/* spt_band.ht_cap */
 
-- 
2.54.0