linux-kernel - [PATCH RT 11/12 rc3] ACPI: Convert embedded controller lock to raw spinlock

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Date:	Mon, 05 Dec 2011 18:00:57 -0500
From:	Steven Rostedt <rostedt@...dmis.org>
To:	linux-kernel@...r.kernel.org,
	linux-rt-users <linux-rt-users@...r.kernel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Carsten Emde <C.Emde@...dl.org>,
	John Kacur <jkacur@...hat.com>,
	Clark Williams <williams@...hat.com>, stable-rt@...r.kernel.org
Subject: [PATCH RT 11/12 rc3] ACPI: Convert embedded controller lock to raw spinlock

From: Clark Williams <williams@...hat.com>

Was seeing multiple "scheduling while atomic" backtraces on the
3.2-rc2-rt5 realtime kernel. This patch converts the spinlock in
the ACPI embedded controller structure (curr_lock) to be a raw
spinlock.

Signed-off-by: Clark Williams <williams@...hat.com>
Link: http://lkml.kernel.org/r/20111203093537.7d805f64@redhat.com
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable-rt@...r.kernel.org
Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
---
 drivers/acpi/ec.c       |   22 +++++++++++-----------
 drivers/acpi/internal.h |    2 +-
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index b19a18d..5812e01 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -152,10 +152,10 @@ static int ec_transaction_done(struct acpi_ec *ec)
 {
 	unsigned long flags;
 	int ret = 0;
-	spin_lock_irqsave(&ec->curr_lock, flags);
+	raw_spin_lock_irqsave(&ec->curr_lock, flags);
 	if (!ec->curr || ec->curr->done)
 		ret = 1;
-	spin_unlock_irqrestore(&ec->curr_lock, flags);
+	raw_spin_unlock_irqrestore(&ec->curr_lock, flags);
 	return ret;
 }
 
@@ -169,7 +169,7 @@ static void start_transaction(struct acpi_ec *ec)
 static void advance_transaction(struct acpi_ec *ec, u8 status)
 {
 	unsigned long flags;
-	spin_lock_irqsave(&ec->curr_lock, flags);
+	raw_spin_lock_irqsave(&ec->curr_lock, flags);
 	if (!ec->curr)
 		goto unlock;
 	if (ec->curr->wlen > ec->curr->wi) {
@@ -194,7 +194,7 @@ err:
 	if (in_interrupt())
 		++ec->curr->irq_count;
 unlock:
-	spin_unlock_irqrestore(&ec->curr_lock, flags);
+	raw_spin_unlock_irqrestore(&ec->curr_lock, flags);
 }
 
 static int acpi_ec_sync_query(struct acpi_ec *ec);
@@ -232,9 +232,9 @@ static int ec_poll(struct acpi_ec *ec)
 		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
 			break;
 		pr_debug(PREFIX "controller reset, restart transaction\n");
-		spin_lock_irqsave(&ec->curr_lock, flags);
+		raw_spin_lock_irqsave(&ec->curr_lock, flags);
 		start_transaction(ec);
-		spin_unlock_irqrestore(&ec->curr_lock, flags);
+		raw_spin_unlock_irqrestore(&ec->curr_lock, flags);
 	}
 	return -ETIME;
 }
@@ -247,17 +247,17 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 	if (EC_FLAGS_MSI)
 		udelay(ACPI_EC_MSI_UDELAY);
 	/* start transaction */
-	spin_lock_irqsave(&ec->curr_lock, tmp);
+	raw_spin_lock_irqsave(&ec->curr_lock, tmp);
 	/* following two actions should be kept atomic */
 	ec->curr = t;
 	start_transaction(ec);
 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
-	spin_unlock_irqrestore(&ec->curr_lock, tmp);
+	raw_spin_unlock_irqrestore(&ec->curr_lock, tmp);
 	ret = ec_poll(ec);
-	spin_lock_irqsave(&ec->curr_lock, tmp);
+	raw_spin_lock_irqsave(&ec->curr_lock, tmp);
 	ec->curr = NULL;
-	spin_unlock_irqrestore(&ec->curr_lock, tmp);
+	raw_spin_unlock_irqrestore(&ec->curr_lock, tmp);
 	return ret;
 }
 
@@ -678,7 +678,7 @@ static struct acpi_ec *make_acpi_ec(void)
 	mutex_init(&ec->lock);
 	init_waitqueue_head(&ec->wait);
 	INIT_LIST_HEAD(&ec->list);
-	spin_lock_init(&ec->curr_lock);
+	raw_spin_lock_init(&ec->curr_lock);
 	return ec;
 }
 
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index ca75b9c..68ed95f 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -62,7 +62,7 @@ struct acpi_ec {
 	wait_queue_head_t wait;
 	struct list_head list;
 	struct transaction *curr;
-	spinlock_t curr_lock;
+	raw_spinlock_t curr_lock;
 };
 
 extern struct acpi_ec *first_ec;
-- 
1.7.7.1



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