Re: [PATCH rc v7 2/6] iommu: Replace per-group resetting_domain with per-gdev blocked flag

[Baolu Lu <baolu.lu@linux.intel.com>]

On 4/19/26 07:41, Nicolin Chen wrote:
> The core tracks device resetting states with a per-group resetting_domain,
> while a reset is actually per group-device. Such a mismatch might lead to
> confusion and even difficulty to untangle per-gdev handling requirement.
> 
> Shuai found that cxl_reset_bus_function() calls pci_reset_bus_function()
> internally while both are calling pci_dev_reset_iommu_prepare/done(). And
> the solution requires the core to track at the group_device level as well.
> 
> Introduce a 'blocked' flag to struct group_device, to allow a multi-device
> group to isolate concurrent device resets independently.
> 
> As the reset routine is per gdev, it cannot clear group->resetting_domain
> without iterating over the device list to ensure no other device is being
> reset. Simplify it by replacing the resetting_domain with a 'recovery_cnt'
> in the struct iommu_group.
> 
> No functional change. But this is essential to apply following bug fixes.
> 
> Fixes: c279e83953d9 ("iommu: Introduce pci_dev_reset_iommu_prepare/done()")
> Cc:stable@vger.kernel.org
> Reported-by: Shuai Xue<xueshuai@linux.alibaba.com>
> Closes:https://lore.kernel.org/all/absKsk7qQOwzhpzv@Asurada-Nvidia/
> Reviewed-by: Shuai Xue<xueshuai@linux.alibaba.com>
> Reviewed-by: Jason Gunthorpe<jgg@nvidia.com>
> Reviewed-by: Kevin Tian<kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen<nicolinc@nvidia.com>
> ---
>   drivers/iommu/iommu.c | 104 ++++++++++++++++++++++++++++++++----------
>   1 file changed, 79 insertions(+), 25 deletions(-)

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>