brcmfmac: Change vif_event_lock to spinlock

Change vif_event_lock to spinlock from mutex, since this lock is
used in wait_event_timeout() via vif_event_equals(). This caused
a warning report as below.

As far as I can see, this lock protects regions where updating
structure members, not function calls. Also, since those
regions are not called from interrupt handlers (of course, it
was a mutex), spin_lock is used instead of spin_lock_irqsave.

[  186.678550] ------------[ cut here ]------------
[  186.678556] WARNING: CPU: 2 PID: 7140 at /home/mhiramat/ksrc/linux/kernel/sched/core.c:7545 __might_sleep+0x7c/0x80
[  186.678560] do not call blocking ops when !TASK_RUNNING; state=2 set at [<ffffffff980d9090>] prepare_to_wait_event+0x60/0x100
[  186.678560] Modules linked in: brcmfmac xt_CHECKSUM rfcomm ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_addrtype br_netfilter xt_tcpudp ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_raw ip6table_security ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_filter ip6_tables iptable_raw iptable_security iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_filter ip_tables x_tables bnep nls_iso8859_1 i2c_designware_platform i2c_designware_core snd_hda_codec_hdmi snd_hda_codec_realtek dcdbas snd_hda_codec_generic snd_hda_intel snd_hda_codec intel_rapl snd_hda_core x86_pkg_temp_thermal intel_powerclamp coretemp
[  186.678594]  snd_pcm crct10dif_pclmul crc32_pclmul aesni_intel aes_x86_64 joydev glue_helper snd_hwdep lrw gf128mul uvcvideo ablk_helper snd_seq_midi cryptd snd_seq_midi_event snd_rawmidi videobuf2_vmalloc videobuf2_memops snd_seq input_leds videobuf2_v4l2 cfg80211 videobuf2_core snd_timer videodev serio_raw btusb snd_seq_device media btrtl rtsx_pci_ms snd mei_me memstick hid_multitouch mei soundcore brcmutil idma64 virt_dma intel_lpss_pci processor_thermal_device intel_soc_dts_iosf hci_uart btbcm btqca btintel bluetooth int3403_thermal dell_smo8800 intel_lpss_acpi intel_lpss int3402_thermal int340x_thermal_zone intel_hid mac_hid int3400_thermal shpchp sparse_keymap acpi_pad acpi_thermal_rel acpi_als kfifo_buf industrialio kvm_intel kvm irqbypass parport_pc ppdev lp parport autofs4 btrfs xor raid6_pq
[  186.678631]  usbhid nouveau ttm i915 rtsx_pci_sdmmc mxm_wmi i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops psmouse drm ahci rtsx_pci nvme nvme_core libahci i2c_hid hid pinctrl_sunrisepoint video wmi pinctrl_intel fjes [last unloaded: brcmfmac]
[  186.678646] CPU: 2 PID: 7140 Comm: wpa_supplicant Not tainted 4.8.0-rc1+ #8
[  186.678647] Hardware name: Dell Inc. XPS 15 9550/0N7TVV, BIOS 01.02.00 04/07/2016
[  186.678648]  0000000000000000 ffff9d8c64b5b900 ffffffff98442f23 ffff9d8c64b5b950
[  186.678651]  0000000000000000 ffff9d8c64b5b940 ffffffff9808b22b 00001d790000000d
[  186.678653]  ffffffff98c75e78 000000000000026c 0000000000000000 ffff9d8c2706d058
[  186.678655] Call Trace:
[  186.678659]  [<ffffffff98442f23>] dump_stack+0x85/0xc2
[  186.678666]  [<ffffffff9808b22b>] __warn+0xcb/0xf0
[  186.678668]  [<ffffffff9808b29f>] warn_slowpath_fmt+0x4f/0x60
[  186.678671]  [<ffffffff980d9090>] ? prepare_to_wait_event+0x60/0x100
[  186.678672]  [<ffffffff980d9090>] ? prepare_to_wait_event+0x60/0x100
[  186.678674]  [<ffffffff980b922c>] __might_sleep+0x7c/0x80
[  186.678680]  [<ffffffff988b0853>] mutex_lock_nested+0x33/0x3b0
[  186.678682]  [<ffffffff980e5d8d>] ? trace_hardirqs_on+0xd/0x10
[  186.678689]  [<ffffffffc0c57d2d>] brcmf_cfg80211_wait_vif_event+0xcd/0x130 [brcmfmac]
[  186.678691]  [<ffffffff980d9190>] ? wake_atomic_t_function+0x60/0x60
[  186.678697]  [<ffffffffc0c628e9>] brcmf_p2p_del_vif+0xf9/0x220 [brcmfmac]
[  186.678702]  [<ffffffffc0c57fab>] brcmf_cfg80211_del_iface+0x21b/0x270 [brcmfmac]
[  186.678716]  [<ffffffffc0b0539e>] nl80211_del_interface+0xfe/0x3a0 [cfg80211]
[  186.678718]  [<ffffffff987ca335>] genl_family_rcv_msg+0x1b5/0x370
[  186.678720]  [<ffffffff980e5d8d>] ? trace_hardirqs_on+0xd/0x10
[  186.678721]  [<ffffffff987ca56d>] genl_rcv_msg+0x7d/0xb0
[  186.678722]  [<ffffffff987ca4f0>] ? genl_family_rcv_msg+0x370/0x370
[  186.678724]  [<ffffffff987c9a47>] netlink_rcv_skb+0x97/0xb0
[  186.678726]  [<ffffffff987ca168>] genl_rcv+0x28/0x40
[  186.678727]  [<ffffffff987c93c3>] netlink_unicast+0x1d3/0x2f0
[  186.678729]  [<ffffffff987c933b>] ? netlink_unicast+0x14b/0x2f0
[  186.678731]  [<ffffffff987c97cb>] netlink_sendmsg+0x2eb/0x3a0
[  186.678733]  [<ffffffff9876dad8>] sock_sendmsg+0x38/0x50
[  186.678734]  [<ffffffff9876e4df>] ___sys_sendmsg+0x27f/0x290
[  186.678737]  [<ffffffff9828b935>] ? mntput_no_expire+0x5/0x3f0
[  186.678739]  [<ffffffff9828b9be>] ? mntput_no_expire+0x8e/0x3f0
[  186.678741]  [<ffffffff9828b935>] ? mntput_no_expire+0x5/0x3f0
[  186.678743]  [<ffffffff9828bd44>] ? mntput+0x24/0x40
[  186.678744]  [<ffffffff98267830>] ? __fput+0x190/0x200
[  186.678746]  [<ffffffff9876f125>] __sys_sendmsg+0x45/0x80
[  186.678748]  [<ffffffff9876f172>] SyS_sendmsg+0x12/0x20
[  186.678749]  [<ffffffff988b5680>] entry_SYSCALL_64_fastpath+0x23/0xc1
[  186.678751]  [<ffffffff980e2b8f>] ? trace_hardirqs_off_caller+0x1f/0xc0
[  186.678752] ---[ end trace e224d66c5d8408b5 ]---
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c

@@ -5635,7 +5635,7 @@ static s32 brcmf_notify_vif_event(struct brcmf_if *ifp,
 		  ifevent->action, ifevent->flags, ifevent->ifidx,
 		  ifevent->bsscfgidx);
 
-	mutex_lock(&event->vif_event_lock);
+	spin_lock(&event->vif_event_lock);
 	event->action = ifevent->action;
 	vif = event->vif;
 
@@ -5643,7 +5643,7 @@ static s32 brcmf_notify_vif_event(struct brcmf_if *ifp,
 	case BRCMF_E_IF_ADD:
 		/* waiting process may have timed out */
 		if (!cfg->vif_event.vif) {
-			mutex_unlock(&event->vif_event_lock);
+			spin_unlock(&event->vif_event_lock);
 			return -EBADF;
 		}
 
@@ -5654,24 +5654,24 @@ static s32 brcmf_notify_vif_event(struct brcmf_if *ifp,
 			ifp->ndev->ieee80211_ptr = &vif->wdev;
 			SET_NETDEV_DEV(ifp->ndev, wiphy_dev(cfg->wiphy));
 		}
-		mutex_unlock(&event->vif_event_lock);
+		spin_unlock(&event->vif_event_lock);
 		wake_up(&event->vif_wq);
 		return 0;
 
 	case BRCMF_E_IF_DEL:
-		mutex_unlock(&event->vif_event_lock);
+		spin_unlock(&event->vif_event_lock);
 		/* event may not be upon user request */
 		if (brcmf_cfg80211_vif_event_armed(cfg))
 			wake_up(&event->vif_wq);
 		return 0;
 
 	case BRCMF_E_IF_CHANGE:
-		mutex_unlock(&event->vif_event_lock);
+		spin_unlock(&event->vif_event_lock);
 		wake_up(&event->vif_wq);
 		return 0;
 
 	default:
-		mutex_unlock(&event->vif_event_lock);
+		spin_unlock(&event->vif_event_lock);
 		break;
 	}
 	return -EINVAL;
@@ -5792,7 +5792,7 @@ static void wl_deinit_priv(struct brcmf_cfg80211_info *cfg)
 static void init_vif_event(struct brcmf_cfg80211_vif_event *event)
 {
 	init_waitqueue_head(&event->vif_wq);
-	mutex_init(&event->vif_event_lock);
+	spin_lock_init(&event->vif_event_lock);
 }
 
 static s32 brcmf_dongle_roam(struct brcmf_if *ifp)
@@ -6691,9 +6691,9 @@ static inline bool vif_event_equals(struct brcmf_cfg80211_vif_event *event,
 {
 	u8 evt_action;
 
-	mutex_lock(&event->vif_event_lock);
+	spin_lock(&event->vif_event_lock);
 	evt_action = event->action;
-	mutex_unlock(&event->vif_event_lock);
+	spin_unlock(&event->vif_event_lock);
 	return evt_action == action;
 }
 
@@ -6702,10 +6702,10 @@ void brcmf_cfg80211_arm_vif_event(struct brcmf_cfg80211_info *cfg,
 {
 	struct brcmf_cfg80211_vif_event *event = &cfg->vif_event;
 
-	mutex_lock(&event->vif_event_lock);
+	spin_lock(&event->vif_event_lock);
 	event->vif = vif;
 	event->action = 0;
-	mutex_unlock(&event->vif_event_lock);
+	spin_unlock(&event->vif_event_lock);
 }
 
 bool brcmf_cfg80211_vif_event_armed(struct brcmf_cfg80211_info *cfg)
@@ -6713,9 +6713,9 @@ bool brcmf_cfg80211_vif_event_armed(struct brcmf_cfg80211_info *cfg)
 	struct brcmf_cfg80211_vif_event *event = &cfg->vif_event;
 	bool armed;
 
-	mutex_lock(&event->vif_event_lock);
+	spin_lock(&event->vif_event_lock);
 	armed = event->vif != NULL;
-	mutex_unlock(&event->vif_event_lock);
+	spin_unlock(&event->vif_event_lock);
 
 	return armed;
 }

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.h

@@ -227,7 +227,7 @@ struct escan_info {
  */
 struct brcmf_cfg80211_vif_event {
 	wait_queue_head_t vif_wq;
-	struct mutex vif_event_lock;
+	spinlock_t vif_event_lock;
 	u8 action;
 	struct brcmf_cfg80211_vif *vif;
 };