iommu/amd: Split irq_lookup_table out of the amd_iommu_devtable_lock

The function get_irq_table() reads/writes irq_lookup_table while holding
the amd_iommu_devtable_lock. It also modifies
amd_iommu_dev_table[].data[2].
set_dte_entry() is using amd_iommu_dev_table[].data[0|1] (under the
domain->lock) so it should be okay. The access to the iommu is
serialized with its own (iommu's) lock.

So split out get_irq_table() out of amd_iommu_devtable_lock's lock.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index fcfdce7..a87d2fe 100644 (file)
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -82,6 +82,7 @@
 
 static DEFINE_RWLOCK(amd_iommu_devtable_lock);
 static DEFINE_SPINLOCK(pd_bitmap_lock);
+static DEFINE_SPINLOCK(iommu_table_lock);
 
 /* List of all available dev_data structures */
 static LLIST_HEAD(dev_data_list);
@@ -3623,7 +3624,7 @@ static struct irq_remap_table *alloc_irq_table(u16 devid, bool ioapic)
        unsigned long flags;
        u16 alias;
 
-       write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+       spin_lock_irqsave(&iommu_table_lock, flags);
 
        iommu = amd_iommu_rlookup_table[devid];
        if (!iommu)
@@ -3688,7 +3689,7 @@ out:
        iommu_completion_wait(iommu);
 
 out_unlock:
-       write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+       spin_unlock_irqrestore(&iommu_table_lock, flags);
 
        return table;
 }