vfio iommu: Remove atomicity of ref_count of pinned pages (65817085) · Commits · 戴 / test

vfio_pfn.ref_count is always updated while holding iommu->lock, using atomic variable is overkill. Signed-off-by:

drivers/vfio/vfio_iommu_type1.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -112,7 +112,7 @@ struct vfio_pfn {
		struct rb_node node;
		dma_addr_t iova; /* Device address */
		unsigned long pfn; /* Host pfn */
		atomic_t ref_count;
		unsigned int ref_count;
		};

		struct vfio_regions {
		@@ -233,7 +233,7 @@ static int vfio_add_to_pfn_list(struct vfio_dma *dma, dma_addr_t iova,

		vpfn->iova = iova;
		vpfn->pfn = pfn;
		atomic_set(&vpfn->ref_count, 1);
		vpfn->ref_count = 1;
		vfio_link_pfn(dma, vpfn);
		return 0;
		}
		@@ -251,7 +251,7 @@ static struct vfio_pfn vfio_iova_get_vfio_pfn(struct vfio_dma dma,
		struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);

		if (vpfn)
		atomic_inc(&vpfn->ref_count);
		vpfn->ref_count++;
		return vpfn;
		}

		@@ -259,7 +259,8 @@ static int vfio_iova_put_vfio_pfn(struct vfio_dma dma, struct vfio_pfn vpfn)
		{
		int ret = 0;

		if (atomic_dec_and_test(&vpfn->ref_count)) {
		vpfn->ref_count--;
		if (!vpfn->ref_count) {
		ret = put_pfn(vpfn->pfn, dma->prot);
		vfio_remove_from_pfn_list(dma, vpfn);
		}