On 8/20/2021 4:39 PM, Anthony Yznaga wrote:
> 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@xxxxxxxxxx>
> ---
> v2:
> use Alex Williamson's simplified fix
Hi Anthony, thanks for finding and fixing this. I suggest you modify the commit
message to describe the bug. Something like:
vfio_find_dma_valid is defined to return WAITED on success if it was
necessary to wait. However, the loop forgets the WAITED value returned
by vfio_wait() and returns 0 in a later iteration. Fix it.
With that,
Reviewed-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
- Steve
> 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 0b4f7c174c7a..0e9217687f5c 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -612,17 +612,17 @@ static int vfio_wait(struct vfio_iommu *iommu)
> 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 ret = 0;
>
> do {
> *dma_p = vfio_find_dma(iommu, start, size);
> if (!*dma_p)
> - ret = -EINVAL;
> + return -EINVAL;
> else if (!(*dma_p)->vaddr_invalid)
> - ret = 0;
> + return ret;
> else
> ret = vfio_wait(iommu);
> - } while (ret > 0);
> + } while (ret == WAITED);
>
> return ret;
> }
>
