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iommu/arm-smmu-v3: Pre-allocate a per-master invalidation array

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When a master is attached from an old domain to a new domain, it needs to
build an invalidation array to delete and add the array entries from/onto
the invalidation arrays of those two domains, passed via the to_merge and
to_unref arguments into arm_smmu_invs_merge/unref() respectively.

Since the master->num_streams might differ across masters, a memory would
have to be allocated when building an to_merge/to_unref array which might
fail with -ENOMEM.

On the other hand, an attachment to arm_smmu_blocked_domain must not fail
so it's the best to avoid any memory allocation in that path.

Pre-allocate a fixed size invalidation array for every master. This array
will be used as a scratch to fill dynamically when building a to_merge or
to_unref invs array. Sort fwspec->ids in an ascending order to fit to the
arm_smmu_invs_merge() function.

Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Nicolin Chen 2026-03-17 00:59:20 -07:00 • committed by Will Deacon
commit e3a56b37bf
2 changed files with 45 additions and 4 deletions
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