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dmar: use spin_lock_irqsave() in qi_submit_sync()

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Next patch in the series will use queued invalidation interface
qi_submit_sync() for DMA-remapping aswell, which can be called from interrupt
context.

So use spin_lock_irqsave() instead of spin_lock() in qi_submit_sync().

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Suresh Siddha 2008-10-16 16:31:54 -07:00 committed by David Woodhouse
parent 2e532d68a2
commit f05810c996
1 changed files with 13 additions and 6 deletions
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19
drivers/pci/dmar.c
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@ -580,11 +580,11 @@ void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
hw = qi->desc; hw = qi->desc;
spin_lock(&qi->q_lock); spin_lock_irqsave(&qi->q_lock, flags);
while (qi->free_cnt < 3) { while (qi->free_cnt < 3) {
spin_unlock(&qi->q_lock); spin_unlock_irqrestore(&qi->q_lock, flags);
cpu_relax(); cpu_relax();
spin_lock(&qi->q_lock); spin_lock_irqsave(&qi->q_lock, flags);
} }
index = qi->free_head; index = qi->free_head;
@ -605,15 +605,22 @@ void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
qi->free_head = (qi->free_head + 2) % QI_LENGTH; qi->free_head = (qi->free_head + 2) % QI_LENGTH;
qi->free_cnt -= 2; qi->free_cnt -= 2;
spin_lock_irqsave(&iommu->register_lock, flags); spin_lock(&iommu->register_lock);
/* /*
* update the HW tail register indicating the presence of * update the HW tail register indicating the presence of
* new descriptors. * new descriptors.
*/ */
writel(qi->free_head << 4, iommu->reg + DMAR_IQT_REG); writel(qi->free_head << 4, iommu->reg + DMAR_IQT_REG);
spin_unlock_irqrestore(&iommu->register_lock, flags); spin_unlock(&iommu->register_lock);
while (qi->desc_status[wait_index] != QI_DONE) { while (qi->desc_status[wait_index] != QI_DONE) {
/*
* We will leave the interrupts disabled, to prevent interrupt
* context to queue another cmd while a cmd is already submitted
* and waiting for completion on this cpu. This is to avoid
* a deadlock where the interrupt context can wait indefinitely
* for free slots in the queue.
*/
spin_unlock(&qi->q_lock); spin_unlock(&qi->q_lock);
cpu_relax(); cpu_relax();
spin_lock(&qi->q_lock); spin_lock(&qi->q_lock);
@ -622,7 +629,7 @@ void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
qi->desc_status[index] = QI_DONE; qi->desc_status[index] = QI_DONE;
reclaim_free_desc(qi); reclaim_free_desc(qi);
spin_unlock(&qi->q_lock); spin_unlock_irqrestore(&qi->q_lock, flags);
} }
/* /*