On 8/23/21 7:58 AM, Steven Sistare wrote:
> 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>
Thank, Steve. I'll send out a v3 with the updated commit message.
Anthony
>
> - 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;
>> }
>>
