This adds a mutex to protect from races between gate and ungate
calls colliding.
Cc: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
---
This should fix the race observed by Ohad earlier.
---
drivers/mmc/core/host.c | 11 ++++++++---
include/linux/mmc/host.h | 1 +
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index f74b386..92e3370 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -68,9 +68,9 @@ static void mmc_host_clk_gate_delayed(struct mmc_host *host)
unsigned long flags;
if (!freq) {
- pr_err("%s: frequency set to 0 in disable function, "
- "this means the clock is already disabled.\n",
- mmc_hostname(host));
+ pr_debug("%s: frequency set to 0 in disable function, "
+ "this means the clock is already disabled.\n",
+ mmc_hostname(host));
return;
}
/*
@@ -94,6 +94,7 @@ static void mmc_host_clk_gate_delayed(struct mmc_host *host)
spin_unlock_irqrestore(&host->clk_lock, flags);
return;
}
+ mutex_lock(&host->clk_gate_mutex);
spin_lock_irqsave(&host->clk_lock, flags);
if (!host->clk_requests) {
spin_unlock_irqrestore(&host->clk_lock, flags);
@@ -103,6 +104,7 @@ static void mmc_host_clk_gate_delayed(struct mmc_host *host)
pr_debug("%s: gated MCI clock\n", mmc_hostname(host));
}
spin_unlock_irqrestore(&host->clk_lock, flags);
+ mutex_unlock(&host->clk_gate_mutex);
}
/*
@@ -128,6 +130,7 @@ void mmc_host_clk_ungate(struct mmc_host *host)
{
unsigned long flags;
+ mutex_lock(&host->clk_gate_mutex);
spin_lock_irqsave(&host->clk_lock, flags);
if (host->clk_gated) {
spin_unlock_irqrestore(&host->clk_lock, flags);
@@ -137,6 +140,7 @@ void mmc_host_clk_ungate(struct mmc_host *host)
}
host->clk_requests++;
spin_unlock_irqrestore(&host->clk_lock, flags);
+ mutex_unlock(&host->clk_gate_mutex);
}
/**
@@ -214,6 +218,7 @@ static inline void mmc_host_clk_init(struct mmc_host *host)
host->clk_gated = false;
INIT_WORK(&host->clk_gate_work, mmc_host_clk_gate_work);
spin_lock_init(&host->clk_lock);
+ mutex_init(&host->clk_gate_mutex);
}
/**
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 955bc10..53496bb 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -178,6 +178,7 @@ struct mmc_host {
struct work_struct clk_gate_work; /* delayed clock gate */
unsigned int clk_old; /* old clock value cache */
spinlock_t clk_lock; /* lock for clk fields */
+ struct mutex clk_gate_mutex; /* mutex for clock gating */
#endif
/* host specific block data */
--
1.6.3.3
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