Hello Liakhovetski, Right now I am facing some problem during kernel booting which indicate caused by MMC driver. So I think I encountered the race condition you mentioned below. I have gone through MMC stack code, seems sdhci_set_ios already wrapped by spin lock/unlock, so I am a little not understanding why there is still a race condition? Is this race condition caused by sdhci_set_ios function reenter or something else? Thanks for your help on this. BR Chuanxiao -----Original Message----- From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc-owner@xxxxxxxxxxxxxxx] On Behalf Of Guennadi Liakhovetski Sent: Saturday, April 16, 2011 2:08 AM To: linux-sh@xxxxxxxxxxxxxxx Cc: linux-mmc@xxxxxxxxxxxxxxx; Magnus Damm; Simon Horman; Linus Walleij Subject: [PATCH] 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: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> Cc: Simon Horman <horms@xxxxxxxxxxxx> Cc: Magnus Damm <damm@xxxxxxxxxxxxx> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> --- drivers/mmc/core/host.c | 9 ++++----- include/linux/mmc/host.h | 1 - 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 461e6a1..2b200c1 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -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); } /** diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index bcb793e..eb792cb 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -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 */ -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
