From: Clark Williams Date: Sat Dec 3 09:15:46 2011 -0600 Subject: ACPI: Convert embedded controller lock to raw spinlock 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 Link: http://lkml.kernel.org/r/20111203093537.7d805f64@redhat.com Signed-off-by: Thomas Gleixner Cc: stable-rt@vger.kernel.org --- drivers/acpi/ec.c | 22 +++++++++++----------- drivers/acpi/internal.h | 2 +- 2 files changed, 12 insertions(+), 12 deletions(-) Index: linux-3.2/drivers/acpi/ec.c =================================================================== --- linux-3.2.orig/drivers/acpi/ec.c +++ linux-3.2/drivers/acpi/ec.c @@ -152,10 +152,10 @@ static int ec_transaction_done(struct ac { 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 acp 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( 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; } Index: linux-3.2/drivers/acpi/internal.h =================================================================== --- linux-3.2.orig/drivers/acpi/internal.h +++ linux-3.2/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;