netdev - [PATCH v3 04/10] iommu/dma: Use the gfp parameter in __iommu_dma_alloc

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Message-Id: <4-v3-76b587fe28df+6e3-iommu_map_gfp_jgg@nvidia.com>
Date:   Mon, 23 Jan 2023 16:35:57 -0400
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Lu Baolu <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        Kevin Tian <kevin.tian@...el.com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Robin Murphy <robin.murphy@....com>
Cc:     Alex Williamson <alex.williamson@...hat.com>,
        ath10k@...ts.infradead.org, ath11k@...ts.infradead.org,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        dri-devel@...ts.freedesktop.org, iommu@...ts.linux.dev,
        kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-media@...r.kernel.org,
        linux-rdma@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-s390@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-tegra@...r.kernel.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org, nouveau@...ts.freedesktop.org,
        Niklas Schnelle <schnelle@...ux.ibm.com>,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH v3 04/10] iommu/dma: Use the gfp parameter in __iommu_dma_alloc_noncontiguous()

This function does an allocation of a buffer to return to the caller and
then goes on to allocate some internal memory, eg the scatterlist and
IOPTEs.

Instead of hard wiring GFP_KERNEL and a wrong GFP_ATOMIC, continue to use
the passed in gfp flags for all of the allocations. Clear the zone and
policy bits that are only relevant for the buffer allocation before
re-using them for internal allocations.

Auditing says this is never called from an atomic context, so the
GFP_ATOMIC is the incorrect flag.

Reviewed-by: Kevin Tian <kevin.tian@...el.com>
Signed-off-by: Jason Gunthorpe <jgg@...dia.com>
---
 drivers/iommu/dma-iommu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 72cfa24503b8bc..c99e4bc55d8cb0 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -822,7 +822,14 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
 	if (!iova)
 		goto out_free_pages;
 
-	if (sg_alloc_table_from_pages(sgt, pages, count, 0, size, GFP_KERNEL))
+	/*
+	 * Remove the zone/policy flags from the GFP - these are applied to the
+	 * __iommu_dma_alloc_pages() but are not used for the supporting
+	 * internal allocations that follow.
+	 */
+	gfp &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM | __GFP_COMP);
+
+	if (sg_alloc_table_from_pages(sgt, pages, count, 0, size, gfp))
 		goto out_free_iova;
 
 	if (!(ioprot & IOMMU_CACHE)) {
@@ -834,7 +841,7 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
 	}
 
 	ret = iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, ioprot,
-			   GFP_ATOMIC);
+			   gfp);
 	if (ret < 0 || ret < size)
 		goto out_free_sg;
 
-- 
2.39.0