2022-12-03 07:42:30

by Ryder Lee

Subject: [PATCH] wifi: mt76: mt7915: split mcu chan_mib array up

The current flow confuses coverity check that leads to false reporting,
so split the offs[] into two pieces according to chipset revision to
silence coverity tool.

Signed-off-by: Ryder Lee <[email protected]>
---
.../net/wireless/mediatek/mt76/mt7915/mcu.c | 50 ++++++++++---------
1 file changed, 27 insertions(+), 23 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
index b2652de082ba..ca315af3905b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -2974,38 +2974,42 @@ int mt7915_mcu_apply_tx_dpd(struct mt7915_phy *phy)

int mt7915_mcu_get_chan_mib_info(struct mt7915_phy *phy, bool chan_switch)
{
- /* strict order */
- static const u32 offs[] = {
- MIB_NON_WIFI_TIME,
- MIB_TX_TIME,
- MIB_RX_TIME,
- MIB_OBSS_AIRTIME,
- MIB_TXOP_INIT_COUNT,
- /* v2 */
- MIB_NON_WIFI_TIME_V2,
- MIB_TX_TIME_V2,
- MIB_RX_TIME_V2,
- MIB_OBSS_AIRTIME_V2
- };
struct mt76_channel_state *state = phy->mt76->chan_state;
struct mt76_channel_state *state_ts = &phy->state_ts;
struct mt7915_dev *dev = phy->dev;
struct mt7915_mcu_mib *res, req[5];
struct sk_buff *skb;
- int i, ret, start = 0, ofs = 20;
+ static const u32 *offs;
+ int i, ret, len, offs_cc;
u64 cc_tx;

- if (!is_mt7915(&dev->mt76)) {
- start = 5;
- ofs = 0;
+ /* strict order */
+ if (is_mt7915(&dev->mt76)) {
+ static const u32 chip_offs[] = {
+ MIB_NON_WIFI_TIME,
+ MIB_TX_TIME,
+ MIB_RX_TIME,
+ MIB_OBSS_AIRTIME,
+ MIB_TXOP_INIT_COUNT,
+ };
+ len = ARRAY_SIZE(chip_offs);
+ offs = chip_offs;
+ offs_cc = 20;
+ } else {
+ static const u32 chip_offs[] = {
+ MIB_NON_WIFI_TIME_V2,
+ MIB_TX_TIME_V2,
+ MIB_RX_TIME_V2,
+ MIB_OBSS_AIRTIME_V2
+ };
+ len = ARRAY_SIZE(chip_offs);
+ offs = chip_offs;
+ offs_cc = 0;
}

- for (i = 0; i < 5; i++) {
+ for (i = 0; i < len; i++) {
req[i].band = cpu_to_le32(phy->mt76->band_idx);
- req[i].offs = cpu_to_le32(offs[i + start]);
-
- if (!is_mt7915(&dev->mt76) && i == 3)
- break;
+ req[i].offs = cpu_to_le32(offs[i]);
}

ret = mt76_mcu_send_and_get_msg(&dev->mt76, MCU_EXT_CMD(GET_MIB_INFO),
@@ -3013,7 +3017,7 @@ int mt7915_mcu_get_chan_mib_info(struct mt7915_phy *phy, bool chan_switch)
if (ret)
return ret;

- res = (struct mt7915_mcu_mib *)(skb->data + ofs);
+ res = (struct mt7915_mcu_mib *)(skb->data + offs_cc);

#define __res_u64(s) le64_to_cpu(res[s].data)
/* subtract Tx backoff time from Tx duration */
--
2.18.0

2022-12-05 14:31:12

by AngeloGioacchino Del Regno

Subject: Re: [PATCH] wifi: mt76: mt7915: split mcu chan_mib array up

Il 03/12/22 08:37, Ryder Lee ha scritto:
> The current flow confuses coverity check that leads to false reporting,
> so split the offs[] into two pieces according to chipset revision to
> silence coverity tool.
>
> Signed-off-by: Ryder Lee <[email protected]>
> ---
> .../net/wireless/mediatek/mt76/mt7915/mcu.c | 50 ++++++++++---------
> 1 file changed, 27 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> index b2652de082ba..ca315af3905b 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> @@ -2974,38 +2974,42 @@ int mt7915_mcu_apply_tx_dpd(struct mt7915_phy *phy)
>
> int mt7915_mcu_get_chan_mib_info(struct mt7915_phy *phy, bool chan_switch)
> {
> - /* strict order */
> - static const u32 offs[] = {
> - MIB_NON_WIFI_TIME,
> - MIB_TX_TIME,
> - MIB_RX_TIME,
> - MIB_OBSS_AIRTIME,
> - MIB_TXOP_INIT_COUNT,
> - /* v2 */
> - MIB_NON_WIFI_TIME_V2,
> - MIB_TX_TIME_V2,
> - MIB_RX_TIME_V2,
> - MIB_OBSS_AIRTIME_V2
> - };
> struct mt76_channel_state *state = phy->mt76->chan_state;
> struct mt76_channel_state *state_ts = &phy->state_ts;
> struct mt7915_dev *dev = phy->dev;
> struct mt7915_mcu_mib *res, req[5];
> struct sk_buff *skb;
> - int i, ret, start = 0, ofs = 20;
> + static const u32 *offs;
> + int i, ret, len, offs_cc;
> u64 cc_tx;
>

A more readable option would be

/* strict order */
static const u32 chip_offs_v1[] = {
MIB_NON_WIFI_TIME,
MIB_TX_TIME,
MIB_RX_TIME,
MIB_OBSS_AIRTIME,
MIB_TXOP_INIT_COUNT,
};

static const u32 chip_offs_v2[] = {
MIB_NON_WIFI_TIME_V2,
MIB_TX_TIME_V2,
MIB_RX_TIME_V2,
MIB_OBSS_AIRTIME_V2
};

if (is_mt7915(&dev->mt76)) {
len = ARRAY_SIZE(chip_offs_v1);
offs = chip_offs_v1;
offs_cc = 20;
} else {
len = ARRAY_SIZE(chip_offs_v2);
offs = chip_offs_v2;
offs_cc = 20;
}

Regards,
Angelo