From 599bec2e07cb46367788e4dcdc90700ded19a508 Mon Sep 17 00:00:00 2001 From: Naman Padhiar Date: Tue, 17 Nov 2020 16:00:54 +0530 Subject: [PATCH] icnss2: Avoid race between soc wake release threads Avoid race condition between soc wake release from queue context and host driver context. Change-Id: I6e20a9a8781f65447e89160ff4e362a04ec4ec5c Signed-off-by: Naman Padhiar --- drivers/soc/qcom/icnss2/main.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/soc/qcom/icnss2/main.c b/drivers/soc/qcom/icnss2/main.c index eec972a1bb34..35e6501242f4 100644 --- a/drivers/soc/qcom/icnss2/main.c +++ b/drivers/soc/qcom/icnss2/main.c @@ -986,6 +986,19 @@ static int icnss_qdss_trace_save_hdlr(struct icnss_priv *priv, return ret; } +static inline int icnss_atomic_dec_if_greater_one(atomic_t *v) +{ + int dec, c = atomic_read(v); + + do { + dec = c - 1; + if (unlikely(dec < 1)) + break; + } while (!atomic_try_cmpxchg(v, &c, dec)); + + return dec; +} + static int icnss_event_soc_wake_request(struct icnss_priv *priv, void *data) { int ret = 0; @@ -2365,7 +2378,6 @@ EXPORT_SYMBOL(icnss_force_wake_request); int icnss_force_wake_release(struct device *dev) { struct icnss_priv *priv = dev_get_drvdata(dev); - int count = 0; if (!dev) return -ENODEV; @@ -2375,15 +2387,14 @@ int icnss_force_wake_release(struct device *dev) return -EINVAL; } - if (atomic_read(&priv->soc_wake_ref_count) > 1) { - count = atomic_dec_return(&priv->soc_wake_ref_count); + icnss_pr_dbg("Calling SOC Wake response"); + + if (icnss_atomic_dec_if_greater_one(&priv->soc_wake_ref_count)) { icnss_pr_dbg("SOC previous release pending, Ref count: %d", - count); + atomic_read(&priv->soc_wake_ref_count)); return 0; } - icnss_pr_dbg("Calling SOC Wake response"); - icnss_soc_wake_event_post(priv, ICNSS_SOC_WAKE_RELEASE_EVENT, 0, NULL);