linux-kernel - [PATCH v6 04/17] iommu: add kernel-doc for iommu_unmap and iommu_unmap

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Message-ID: <0ae577f8b99f7e03c679729434c87ea7daf78955.1737106761.git.leon@kernel.org>
Date: Fri, 17 Jan 2025 12:03:35 +0200
From: Leon Romanovsky <leon@...nel.org>
To: Christoph Hellwig <hch@....de>,
	Jason Gunthorpe <jgg@...pe.ca>,
	Robin Murphy <robin.murphy@....com>
Cc: Leon Romanovsky <leonro@...dia.com>,
	Jens Axboe <axboe@...nel.dk>,
	Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>,
	Sagi Grimberg <sagi@...mberg.me>,
	"Keith Busch" <kbusch@...nel.org>,
	"Bjorn Helgaas" <bhelgaas@...gle.com>,
	"Logan Gunthorpe" <logang@...tatee.com>,
	"Yishai Hadas" <yishaih@...dia.com>,
	"Shameer Kolothum" <shameerali.kolothum.thodi@...wei.com>,
	"Kevin Tian" <kevin.tian@...el.com>,
	"Alex Williamson" <alex.williamson@...hat.com>,
	"Marek Szyprowski" <m.szyprowski@...sung.com>,
	Jérôme Glisse <jglisse@...hat.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Jonathan Corbet" <corbet@....net>,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-block@...r.kernel.org,
	linux-rdma@...r.kernel.org,
	iommu@...ts.linux.dev,
	linux-nvme@...ts.infradead.org,
	linux-pci@...r.kernel.org,
	kvm@...r.kernel.org,
	linux-mm@...ck.org,
	"Randy Dunlap" <rdunlap@...radead.org>,
	Jason Gunthorpe <jgg@...dia.com>
Subject: [PATCH v6 04/17] iommu: add kernel-doc for iommu_unmap and iommu_unmap_fast

From: Leon Romanovsky <leonro@...dia.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@...dia.com>
Acked-by: Will Deacon <will@...nel.org>
Reviewed-by: Christoph Hellwig <hch@....de>
Signed-off-by: Leon Romanovsky <leonro@...dia.com>
---
 drivers/iommu/iommu.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ec75d14497bf..c86a57abe292 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2590,6 +2590,25 @@ 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 can't 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.
+ *
+ * Basically iommu_unmap_fast() is the same as iommu_unmap() but for callers
+ * which manage the IOTLB flushing externally to perform a 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)
-- 
2.47.1