On Sat, Dec 05, 2020 at 04:29:57PM +0800, Keqian Zhu wrote:
> ... then we have more chance to detect wrong code logic.
This could do with being a bit more explicit. Something like:
Although handling a mapping request with no permissions is a
trivial no-op, defer the early return until after the size/range
checks so that we are consistent with other mapping requests.
> Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
> ---
> drivers/iommu/io-pgtable-arm.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index a7a9bc08dcd1..8ade72adab31 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -444,10 +444,6 @@ static int arm_lpae_map(struct io_pgtable_ops *ops,
> unsigned long iova,
> arm_lpae_iopte prot;
> long iaext = (s64)iova >> cfg->ias;
>
> - /* If no access, then nothing to do */
> - if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
> - return 0;
> -
> if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
> return -EINVAL;
>
> @@ -456,6 +452,10 @@ static int arm_lpae_map(struct io_pgtable_ops *ops,
> unsigned long iova,
> if (WARN_ON(iaext || paddr >> cfg->oas))
> return -ERANGE;
>
> + /* If no access, then nothing to do */
> + if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
> + return 0;
This looks sensible to me, but please can you make the same change for
io-pgtable-arm-v7s.c so that the behaviour is consistent across the two
formats?
Thanks,
Will
