The current IOVA allocation code stores a cached copy of the first allocated IOVA address node, and all the subsequent allocations have no way to get past(higher than) the first allocated IOVA range.
This causes issue when dma_mask for the master device is changed. Though the DMA window is increased, the allocation code unaware of the change, goes ahead allocating IOVA address lower than the first allocated IOVA address. This patch adds a check for dma_mask change in the IOVA allocation function and resets the cached IOVA node to anchor node everytime the dma_mask change is observed. NOTE: This patch is needed to address the issue discussed in below thread: https://www.spinics.net/lists/iommu/msg43586.html Signed-off-by: Ajay Kumar <ajaykumar...@samsung.com> Signed-off-by: Sathyam Panda <sathya.pa...@samsung.com> --- drivers/iommu/iova.c | 17 ++++++++++++++++- include/linux/iova.h | 1 + 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 41c605b0058f..0e99975036ae 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -44,6 +44,7 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule, iovad->granule = granule; iovad->start_pfn = start_pfn; iovad->dma_32bit_pfn = 1UL << (32 - iova_shift(iovad)); + iovad->curr_limit_pfn = iovad->dma_32bit_pfn; iovad->max32_alloc_size = iovad->dma_32bit_pfn; iovad->flush_cb = NULL; iovad->fq = NULL; @@ -116,9 +117,20 @@ EXPORT_SYMBOL_GPL(init_iova_flush_queue); static struct rb_node * __get_cached_rbnode(struct iova_domain *iovad, unsigned long limit_pfn) { - if (limit_pfn <= iovad->dma_32bit_pfn) + if (limit_pfn <= iovad->dma_32bit_pfn) { + /* re-init cached node if DMA limit has changed */ + if (limit_pfn != iovad->curr_limit_pfn) { + iovad->cached32_node = &iovad->anchor.node; + iovad->curr_limit_pfn = limit_pfn; + } return iovad->cached32_node; + } + /* re-init cached node if DMA limit has changed */ + if (limit_pfn != iovad->curr_limit_pfn) { + iovad->cached_node = &iovad->anchor.node; + iovad->curr_limit_pfn = limit_pfn; + } return iovad->cached_node; } @@ -190,6 +202,9 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, if (size_aligned) align_mask <<= fls_long(size - 1); + if (limit_pfn != iovad->curr_limit_pfn) + iovad->max32_alloc_size = iovad->dma_32bit_pfn; + /* Walk the tree backwards */ spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); if (limit_pfn <= iovad->dma_32bit_pfn && diff --git a/include/linux/iova.h b/include/linux/iova.h index a0637abffee8..be2220c096ef 100644 --- a/include/linux/iova.h +++ b/include/linux/iova.h @@ -73,6 +73,7 @@ struct iova_domain { unsigned long granule; /* pfn granularity for this domain */ unsigned long start_pfn; /* Lower limit for this domain */ unsigned long dma_32bit_pfn; + unsigned long curr_limit_pfn; /* Current max limit for this domain */ unsigned long max32_alloc_size; /* Size of last failed allocation */ struct iova_fq __percpu *fq; /* Flush Queue */ -- 2.17.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
