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

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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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <damm@opensource.se>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <stable@kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Guennadi Liakhovetski 2011-04-15 20:08:19 +02:00 committed by Chris Ball
parent f694751421
commit 26fc8775b5
2 changed files with 4 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/mmc/core/host.c
View File

@ -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);
}
/**

1
include/linux/mmc/host.h
View File

@ -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 */