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Subject[PATCH 03/10] iommu/amd: split domain id out of amd_iommu_devtable_lock
Date
domain_id_alloc() and domain_id_free() is used for id management. Those
two function share a bitmap (amd_iommu_pd_alloc_bitmap) and set/clear
bits based on id allocation. There is no need to share this with
amd_iommu_devtable_lock, it can use its own lock for this operation.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/iommu/amd_iommu.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 0e57ce2c258b..692b2e3b9af1 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -81,6 +81,7 @@
#define AMD_IOMMU_PGSIZES ((~0xFFFUL) & ~(2ULL << 38))

static DEFINE_RWLOCK(amd_iommu_devtable_lock);
+static DEFINE_SPINLOCK(pd_bitmap_lock);

/* List of all available dev_data structures */
static LLIST_HEAD(dev_data_list);
@@ -1600,29 +1601,26 @@ static void del_domain_from_list(struct protection_domain *domain)

static u16 domain_id_alloc(void)
{
- unsigned long flags;
int id;

- write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+ spin_lock(&pd_bitmap_lock);
id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID);
BUG_ON(id == 0);
if (id > 0 && id < MAX_DOMAIN_ID)
__set_bit(id, amd_iommu_pd_alloc_bitmap);
else
id = 0;
- write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+ spin_unlock(&pd_bitmap_lock);

return id;
}

static void domain_id_free(int id)
{
- unsigned long flags;
-
- write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+ spin_lock(&pd_bitmap_lock);
if (id > 0 && id < MAX_DOMAIN_ID)
__clear_bit(id, amd_iommu_pd_alloc_bitmap);
- write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+ spin_unlock(&pd_bitmap_lock);
}

#define DEFINE_FREE_PT_FN(LVL, FN) \
--
2.16.2
\
 
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