Re: [PATCH] iommu/arm-smmu-v3: Allow stream table to have nodes with the same ID

Jason Gunthorpe
2025-04-11T11:54:49Z

On Thu, Apr 10, 2025 at 09:47:06PM -0700, Nicolin Chen wrote:
> Change the arm_smmu_streams_cmp_node() to allow the stream table to hold
> multiple nodes with the same Stream ID. Meanwhile, the reverse lookup from
> the Stream ID to a device pointer will have to be broken, i.e. the eventq
> handler will no longer find the device with a Stream ID in such cases.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Tested-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 31 +++++++++++++++++++--
> 1 file changed, 29 insertions(+), 2 deletions(-)

This should go to rc, also a fixes line is probably something like:

Fixes: cdf315f907d4 ("iommu/arm-smmu-v3: Maintain a SID->device structure")

Since it has been broken for a while, it just didn't become critical
until probe started failing in v6.15-rc1

Jason