iommu/arm-smmu-v3: Fix smmu_domain->nr_ats_masters decrement

The arm_smmu_attach_commit() updates master->ats_enabled before calling
arm_smmu_remove_master_domain() that is supposed to clean up everything
in the old domain, including the old domain's nr_ats_masters. So, it is
supposed to use the old ats_enabled state of the device, not an updated
state.

This isn't a problem if switching between two domains where:
 - old ats_enabled = false; new ats_enabled = false
 - old ats_enabled = true;  new ats_enabled = true
but can fail cases where:
 - old ats_enabled = false; new ats_enabled = true
   (old domain should keep the counter but incorrectly decreased it)
 - old ats_enabled = true;  new ats_enabled = false
   (old domain needed to decrease the counter but incorrectly missed it)

Update master->ats_enabled after arm_smmu_remove_master_domain() to fix
this.

Fixes: 7497f4211f4f ("iommu/arm-smmu-v3: Make changing domains be hitless for ATS")
Cc: [email protected]
Signed-off-by: Nicolin Chen <[email protected]>
Acked-by: Will Deacon <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Pranjal Shrivastava <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

0 files changed, 0 insertions, 0 deletions