ath10k: sdio: Add missing BH locking around napi_schdule()
authorFabio Estevam <festevam@denx.de>
Tue, 28 Sep 2021 11:00:47 +0000 (14:00 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 18 Nov 2021 18:16:27 +0000 (19:16 +0100)
commit092e6cb650ebeae4540fd3844d25a8688566bf32
treeab2d99de9e77bddf9955a13b7e3201afe13c3d67
parent63287a77b1382bfbc9f9ce57fcf64534bb31a273
ath10k: sdio: Add missing BH locking around napi_schdule()

[ Upstream commit 019edd01d174ce4bb2e517dd332922514d176601 ]

On a i.MX-based board with a QCA9377 Wifi chip, the following errors
are seen after launching the 'hostapd' application:

hostapd /etc/wifi.conf
Configuration file: /etc/wifi.conf
wlan0: interface state UNINITIALIZED->COUNTRY_UPDATE
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
Using interface wlan0 with hwaddr 00:1f:7b:31:04:a0 and ssid "thessid"
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
wlan0: interface state COUNTRY_UPDATE->ENABLED
wlan0: AP-ENABLED
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
...

Fix this problem by adding the BH locking around napi-schedule(),
in the same way it was done in commit e63052a5dd3c ("mlx5e: add
add missing BH locking around napi_schdule()").

Its commit log provides the following explanation:

"It's not correct to call napi_schedule() in pure process
context. Because we use __raise_softirq_irqoff() we require
callers to be in a context which will eventually lead to
softirq handling (hardirq, bh disabled, etc.).

With code as is users will see:

NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
"

Fixes: cfee8793a74d ("ath10k: enable napi on RX path for sdio")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210824144339.2796122-1-festevam@denx.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/wireless/ath/ath10k/sdio.c