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Commit 3b8f4048 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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locking, x86, iommu: Annotate qi->q_lock as raw 



The qi->q_lock lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 96f8e98b

drivers/iommu/dmar.c

+7 −7
Original line number Diff line number Diff line
@@ -921,11 +921,11 @@ int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu) 
restart:

	rc = 0;



	spin_lock_irqsave(&qi->q_lock, flags);

	raw_spin_lock_irqsave(&qi->q_lock, flags);

	while (qi->free_cnt < 3) {

		spin_unlock_irqrestore(&qi->q_lock, flags);

		raw_spin_unlock_irqrestore(&qi->q_lock, flags);

		cpu_relax();

		spin_lock_irqsave(&qi->q_lock, flags);

		raw_spin_lock_irqsave(&qi->q_lock, flags);

	}



	index = qi->free_head;
@@ -965,15 +965,15 @@ int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu) 
		if (rc)

			break;



		spin_unlock(&qi->q_lock);

		raw_spin_unlock(&qi->q_lock);

		cpu_relax();

		spin_lock(&qi->q_lock);

		raw_spin_lock(&qi->q_lock);

	}



	qi->desc_status[index] = QI_DONE;



	reclaim_free_desc(qi);

	spin_unlock_irqrestore(&qi->q_lock, flags);

	raw_spin_unlock_irqrestore(&qi->q_lock, flags);



	if (rc == -EAGAIN)

		goto restart;
@@ -1159,7 +1159,7 @@ int dmar_enable_qi(struct intel_iommu *iommu) 
	qi->free_head = qi->free_tail = 0;

	qi->free_cnt = QI_LENGTH;



	spin_lock_init(&qi->q_lock);

	raw_spin_lock_init(&qi->q_lock);



	__dmar_enable_qi(iommu);

include/linux/intel-iommu.h

+1 −1
Original line number Diff line number Diff line
@@ -271,7 +271,7 @@ struct qi_desc { 
};



struct q_inval {

	spinlock_t      q_lock;

	raw_spinlock_t  q_lock;

	struct qi_desc  *desc;          /* invalidation queue */

	int             *desc_status;   /* desc status */

	int             free_head;      /* first free entry */