Hi Linus,
Please pull from:
git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc.git for-linus
to revert mainline commit 26fc8775b51484 ("mmc: fix a race between
card-detect rescan and clock-gate work instances"), merged in .39-rc6.
We've received reports from Archlinux users that this patch causes
a boot time crash when probing MMC cards with CONFIG_MMC_CLKGATE=y.
I can't reproduce this myself, but I'd be more comfortable releasing
.39 with the previous behavior while we investigate. Thanks.
The following changes since commit eed631e0d741d1a1067cfc6d709fdf2363126f9c:
Linus Torvalds (1):
Merge git://git.kernel.org/.../mason/btrfs-unstable
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc.git for-linus
Chris Ball (1):
Revert "mmc: fix a race between card-detect rescan and clock-gate work instances"
drivers/mmc/core/host.c | 9 +++++----
include/linux/mmc/host.h | 1 +
2 files changed, 6 insertions(+), 4 deletions(-)
From: Chris Ball <cjb@xxxxxxxxxx>
Date: Mon, 16 May 2011 11:32:26 -0400
Subject: [PATCH] Revert "mmc: fix a race between card-detect rescan and clock-gate work instances"
This reverts commit 26fc8775b51484d8c0a671198639c6d5ae60533e, which has
been reported to cause boot/resume-time crashes for some users:
https://bbs.archlinux.org/viewtopic.php?id=118751.
Signed-off-by: Chris Ball <cjb@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
---
drivers/mmc/core/host.c | 9 +++++----
include/linux/mmc/host.h | 1 +
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 2b200c1..461e6a1 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;
}
- mmc_claim_host(host);
+ mutex_lock(&host->clk_gate_mutex);
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);
- mmc_release_host(host);
+ mutex_unlock(&host->clk_gate_mutex);
}
/*
@@ -130,7 +130,7 @@ void mmc_host_clk_ungate(struct mmc_host *host)
{
unsigned long flags;
- mmc_claim_host(host);
+ mutex_lock(&host->clk_gate_mutex);
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);
- mmc_release_host(host);
+ mutex_unlock(&host->clk_gate_mutex);
}
/**
@@ -215,6 +215,7 @@ 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 eb792cb..bcb793e 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -183,6 +183,7 @@ 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 */
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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