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Commit 26fc8775 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
Browse files

mmc: fix a race between card-detect rescan and clock-gate work instances 



Currently there is a race in the MMC core between a card-detect
rescan work and the clock-gating work, scheduled from a command
completion. Fix it by removing the dedicated clock-gating mutex
and using the MMC standard locking mechanism instead.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <damm@opensource.se>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Cc: <stable@kernel.org>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent f6947514

drivers/mmc/core/host.c

+4 −5
Original line number Diff line number Diff line
@@ -94,7 +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);

	mmc_claim_host(host);

	spin_lock_irqsave(&host->clk_lock, flags);

	if (!host->clk_requests) {

		spin_unlock_irqrestore(&host->clk_lock, flags);
@@ -104,7 +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);

	mmc_release_host(host);

}



/*
@@ -130,7 +130,7 @@ void mmc_host_clk_ungate(struct mmc_host *host) 
{

	unsigned long flags;



	mutex_lock(&host->clk_gate_mutex);

	mmc_claim_host(host);

	spin_lock_irqsave(&host->clk_lock, flags);

	if (host->clk_gated) {

		spin_unlock_irqrestore(&host->clk_lock, flags);
@@ -140,7 +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);

	mmc_release_host(host);

}



/**
@@ -215,7 +215,6 @@ 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);

}



/**

include/linux/mmc/host.h

+0 −1
Original line number Diff line number Diff line
@@ -183,7 +183,6 @@ 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 */