This is a note to let you know that I've just added the patch titled
dma-iommu: add iommu_dma_opt_mapping_size()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dma-iommu-add-iommu_dma_opt_mapping_size.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5616f15ddd367a2ddb3a67ecdb4fa352ccdc57de
Author: John Garry <john.garry@xxxxxxxxxx>
Date: Thu Jul 14 19:15:25 2022 +0800
dma-iommu: add iommu_dma_opt_mapping_size()
[ Upstream commit 6d9870b7e5def2450e21316515b9efc0529204dd ]
Add the IOMMU callback for DMA mapping API dma_opt_mapping_size(), which
allows the drivers to know the optimal mapping limit and thus limit the
requested IOVA lengths.
This value is based on the IOVA rcache range limit, as IOVAs allocated
above this limit must always be newly allocated, which may be quite slow.
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
Acked-by: Robin Murphy <robin.murphy@xxxxxxx>
Acked-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Stable-dep-of: afc5aa46ed56 ("iommu/dma: Force swiotlb_max_mapping_size on an untrusted device")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8cd63e6ccd2cf..a76a46e94a606 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1291,6 +1291,11 @@ static unsigned long iommu_dma_get_merge_boundary(struct device *dev)
return (1UL << __ffs(domain->pgsize_bitmap)) - 1;
}
+static size_t iommu_dma_opt_mapping_size(void)
+{
+ return iova_rcache_range();
+}
+
static const struct dma_map_ops iommu_dma_ops = {
.alloc = iommu_dma_alloc,
.free = iommu_dma_free,
@@ -1313,6 +1318,7 @@ static const struct dma_map_ops iommu_dma_ops = {
.map_resource = iommu_dma_map_resource,
.unmap_resource = iommu_dma_unmap_resource,
.get_merge_boundary = iommu_dma_get_merge_boundary,
+ .opt_mapping_size = iommu_dma_opt_mapping_size,
};
/*
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 0835f32e040ad..f6dfb9e45e953 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -27,6 +27,11 @@ static void free_iova_rcaches(struct iova_domain *iovad);
static void fq_destroy_all_entries(struct iova_domain *iovad);
static void fq_flush_timeout(struct timer_list *t);
+unsigned long iova_rcache_range(void)
+{
+ return PAGE_SIZE << (IOVA_RANGE_CACHE_MAX_SIZE - 1);
+}
+
static int iova_cpuhp_dead(unsigned int cpu, struct hlist_node *node)
{
struct iova_domain *iovad;
diff --git a/include/linux/iova.h b/include/linux/iova.h
index 6b6cc104e300d..9aa0acf9820af 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -137,6 +137,8 @@ static inline unsigned long iova_pfn(struct iova_domain *iovad, dma_addr_t iova)
int iova_cache_get(void);
void iova_cache_put(void);
+unsigned long iova_rcache_range(void);
+
void free_iova(struct iova_domain *iovad, unsigned long pfn);
void __free_iova(struct iova_domain *iovad, struct iova *iova);
struct iova *alloc_iova(struct iova_domain *iovad, unsigned long size,
