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If it's NULL then there is no need to add page for syncing >> the TLB. > > But that's only because __arm_lpae_unmap() is now choosing to > over-invalidate the table entries for simplicity. I think it would make > more sense to handle that at the callsite, e.g. "if (gather && > !iommu_iotlb_gather_queued(gather))". > > Also doesn't this mean that bisection is broken as-is since patch #1 on > its own is going to blow up dereferencing NULL->pgsize when it gets here? > > Thanks, > Robin. > Yes, gather can be NULL because of patch #1 only. I will fix it at callsite only with a single patch rather than splitting. >> Signed-off-by: Ashish Mhetre >> --- >>   include/linux/iommu.h | 3 +++ >>   1 file changed, 3 insertions(+) >> >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index 4d47f2c33311..2a28c1ef8517 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -928,6 +928,9 @@ static inline void >> iommu_iotlb_gather_add_page(struct iommu_domain *domain, >>                                              struct >> iommu_iotlb_gather *gather, >>                                              unsigned long iova, >> size_t size) >>   { >> +     if (!gather) >> +             return; >> + >>       /* >>        * If the new page is disjoint from the current range or is >> mapped at >>        * a different granularity, then sync the TLB so that the gather