[PATCH] iommu-common: Do not try to deref a null iommu->lazy_flush() pointer when n < pool->hint

[Sowmini Varadhan]

The check for invoking iommu->lazy_flush() from iommu_tbl_range_alloc()
has to be refactored so that we only call ->lazy_flush() if it is non-null.

Signed-off-by: Sowmini Varadhan <sowmini.varad...@oracle.com>
---
 lib/iommu-common.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/iommu-common.c b/lib/iommu-common.c
index ff19f66..b1c93e9 100644
--- a/lib/iommu-common.c
+++ b/lib/iommu-common.c
@@ -21,8 +21,7 @@ static        DEFINE_PER_CPU(unsigned int, iommu_hash_common);
 
 static inline bool need_flush(struct iommu_map_table *iommu)
 {
-       return (iommu->lazy_flush != NULL &&
-               (iommu->flags & IOMMU_NEED_FLUSH) != 0);
+       return ((iommu->flags & IOMMU_NEED_FLUSH) != 0);
 }
 
 static inline void set_flush(struct iommu_map_table *iommu)
@@ -211,7 +210,8 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
                        goto bail;
                }
        }
-       if (n < pool->hint || need_flush(iommu)) {
+       if (iommu->lazy_flush &&
+           (n < pool->hint || need_flush(iommu))) {
                clear_flush(iommu);
                iommu->lazy_flush(iommu);
        }
-- 
1.7.1

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