[PATCH v4 04/18] iommu: add kernel-doc for iommu_unmap and iommu_unmap_fast

[Leon Romanovsky <leon@kernel.org>]

From: Leon Romanovsky <leonro@nvidia.com>

Add kernel-doc section for iommu_unmap and iommu_unmap_fast to document
existing limitation of underlying functions which can't split individual
ranges.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/iommu/iommu.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ec75d14497bf..9eb7c7d7aa70 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2590,6 +2590,24 @@ size_t iommu_unmap(struct iommu_domain *domain,
 }
 EXPORT_SYMBOL_GPL(iommu_unmap);
 
+/**
+ * iommu_unmap_fast() - Remove mappings from a range of IOVA without IOTLB sync
+ * @domain: Domain to manipulate
+ * @iova: IO virtual address to start
+ * @size: Length of the range starting from @iova
+ * @iotlb_gather: range information for a pending IOTLB flush
+ *
+ * iommu_unmap_fast() will remove a translation created by iommu_map(). It cannot
+ * subdivide a mapping created by iommu_map(), so it should be called with IOVA
+ * ranges that match what was passed to iommu_map(). The range can aggregate
+ * contiguous iommu_map() calls so long as no individual range is split.
+ *
+ * Basicly iommu_unmap_fast() as the same as iommu_unmap() but for callers
+ * which manage IOTLB flush range externaly to perform batched sync.
+ *
+ * Returns: Number of bytes of IOVA unmapped. iova + res will be the point
+ * unmapping stopped.
+ */
 size_t iommu_unmap_fast(struct iommu_domain *domain,
 			unsigned long iova, size_t size,
 			struct iommu_iotlb_gather *iotlb_gather)
-- 
2.47.0