... to avoid having multiple spin_unlock_irqrestore() calls.
Signed-off-by: Andrew Cooper <[email protected]>
---
CC: Jan Beulich <[email protected]>
CC: Wei Liu <[email protected]>
CC: Roger Pau Monné <[email protected]>
CC: Boris Ostrovsky <[email protected]>
CC: Suravee Suthikulpanit <[email protected]>
CC: Brian Woods <[email protected]>
Interestingly GCC 6.3 managed to fold disable_iommu() automatically. There is
some partial folding for enable_iommu() (insofar as there is only a single
call to _spin_unlock_irqrestore emitted), but this delta yeilds
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-20 (-20)
Function old new delta
enable_iommu 1844 1824 -20
Total: Before=3340299, After=3340279, chg -0.00%
which means that something wasn't done automatically.
Noticed while investigating the S3 regression.
---
xen/drivers/passthrough/amd/iommu_init.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/xen/drivers/passthrough/amd/iommu_init.c
b/xen/drivers/passthrough/amd/iommu_init.c
index bb9f33e264..bb5a3e57c9 100644
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -899,11 +899,8 @@ static void enable_iommu(struct amd_iommu *iommu)
spin_lock_irqsave(&iommu->lock, flags);
- if ( iommu->enabled )
- {
- spin_unlock_irqrestore(&iommu->lock, flags);
- return;
- }
+ if ( unlikely(iommu->enabled) )
+ goto out;
amd_iommu_erratum_746_workaround(iommu);
@@ -957,6 +954,8 @@ static void enable_iommu(struct amd_iommu *iommu)
amd_iommu_flush_all_caches(iommu);
iommu->enabled = 1;
+
+ out:
spin_unlock_irqrestore(&iommu->lock, flags);
}
@@ -966,11 +965,8 @@ static void disable_iommu(struct amd_iommu *iommu)
spin_lock_irqsave(&iommu->lock, flags);
- if ( !iommu->enabled )
- {
- spin_unlock_irqrestore(&iommu->lock, flags);
- return;
- }
+ if ( unlikely(!iommu->enabled) )
+ goto out;
if ( !iommu->ctrl.int_cap_xt_en )
amd_iommu_msi_enable(iommu, IOMMU_CONTROL_DISABLED);
@@ -988,6 +984,7 @@ static void disable_iommu(struct amd_iommu *iommu)
iommu->enabled = 0;
+ out:
spin_unlock_irqrestore(&iommu->lock, flags);
}
--
2.11.0
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