[PATCH] vfio/type1: Fix vfio_find_dma_valid return

[Anthony Yznaga <anthony.yznaga@oracle.com>]

Fix vfio_find_dma_valid to return WAITED on success if it was necessary
to wait which mean iommu lock was dropped and reacquired.  This allows
vfio_iommu_type1_pin_pages to recheck vaddr_invalid_count and possibly
avoid the checking the validity of every vaddr in its list.

Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
---
 drivers/vfio/vfio_iommu_type1.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index a3e925a41b0d..7ca8c4e95da4 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -612,6 +612,7 @@ static int vfio_find_dma_valid(struct vfio_iommu *iommu, dma_addr_t start,
 			       size_t size, struct vfio_dma **dma_p)
 {
 	int ret;
+	int waited = 0;
 
 	do {
 		*dma_p = vfio_find_dma(iommu, start, size);
@@ -620,10 +621,10 @@ static int vfio_find_dma_valid(struct vfio_iommu *iommu, dma_addr_t start,
 		else if (!(*dma_p)->vaddr_invalid)
 			ret = 0;
 		else
-			ret = vfio_wait(iommu);
+			ret = waited = vfio_wait(iommu);
 	} while (ret > 0);
 
-	return ret;
+	return ret ? ret : waited;
 }
 
 /*
-- 
1.8.3.1