linux-kernel - [PATCH v1] vfio/type1: Remove the almost unused check in vfio_iommu_type1_unpin

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Date:   Tue, 6 Apr 2021 21:50:09 +0800
From:   Shenming Lu <lushenming@...wei.com>
To:     Alex Williamson <alex.williamson@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     <wanghaibin.wang@...wei.com>, <yuzenghui@...wei.com>,
        <lushenming@...wei.com>
Subject: [PATCH v1] vfio/type1: Remove the almost unused check in vfio_iommu_type1_unpin_pages

The check i > npage at the end of vfio_iommu_type1_unpin_pages is unused
unless npage < 0, but if npage < 0, this function will return npage, which
should return -EINVAL instead. So let's just check the parameter npage at
the start of the function. By the way, replace unpin_exit with break.

Signed-off-by: Shenming Lu <lushenming@...wei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 45cbfd4879a5..fd4213c41743 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -960,7 +960,7 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data,
 	bool do_accounting;
 	int i;
 
-	if (!iommu || !user_pfn)
+	if (!iommu || !user_pfn || npage <= 0)
 		return -EINVAL;
 
 	/* Supported for v2 version only */
@@ -977,13 +977,13 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data,
 		iova = user_pfn[i] << PAGE_SHIFT;
 		dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
 		if (!dma)
-			goto unpin_exit;
+			break;
+
 		vfio_unpin_page_external(dma, iova, do_accounting);
 	}
 
-unpin_exit:
 	mutex_unlock(&iommu->lock);
-	return i > npage ? npage : (i > 0 ? i : -EINVAL);
+	return i > 0 ? i : -EINVAL;
 }
 
 static long vfio_sync_unpin(struct vfio_dma *dma, struct vfio_domain *domain,
-- 
2.19.1