iommu/tegra241-cmdqv: Fix warnings due to dmam_free_coherent()

Two WARNINGs are observed when SMMU driver rolls back upon failure:
 arm-smmu-v3.9.auto: Failed to register iommu
 arm-smmu-v3.9.auto: probe with driver arm-smmu-v3 failed with error -22
 ------------[ cut here ]------------
 WARNING: CPU: 5 PID: 1 at kernel/dma/mapping.c:74 dmam_free_coherent+0xc0/0xd8
 Call trace:
  dmam_free_coherent+0xc0/0xd8 (P)
  tegra241_vintf_free_lvcmdq+0x74/0x188
  tegra241_cmdqv_remove_vintf+0x60/0x148
  tegra241_cmdqv_remove+0x48/0xc8
  arm_smmu_impl_remove+0x28/0x60
  devm_action_release+0x1c/0x40
 ------------[ cut here ]------------
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 WARNING: CPU: 16 PID: 1 at mm/page_alloc.c:6902 free_contig_range+0x18c/0x1c8
 Call trace:
  free_contig_range+0x18c/0x1c8 (P)
  cma_release+0x154/0x2f0
  dma_free_contiguous+0x38/0xa0
  dma_direct_free+0x10c/0x248
  dma_free_attrs+0x100/0x290
  dmam_free_coherent+0x78/0xd8
  tegra241_vintf_free_lvcmdq+0x74/0x160
  tegra241_cmdqv_remove+0x98/0x198
  arm_smmu_impl_remove+0x28/0x60
  devm_action_release+0x1c/0x40

This is because the LVCMDQ queue memory are managed by devres, while that
dmam_free_coherent() is called in the context of devm_action_release().

Jason pointed out that "arm_smmu_impl_probe() has mis-ordered the devres
callbacks if ops->device_remove() is going to be manually freeing things
that probe allocated":
https://lore.kernel.org/linux-iommu/20250407174408.GB1722458@nvidia.com/

In fact, tegra241_cmdqv_init_structures() only allocates memory resources
which means any failure that it generates would be similar to -ENOMEM, so
there is no point in having that "falling back to standard SMMU" routine,
as the standard SMMU would likely fail to allocate memory too.

Remove the unwind part in tegra241_cmdqv_init_structures(), and return a
proper error code to ask SMMU driver to call tegra241_cmdqv_remove() via
impl_ops->device_remove(). Then, drop tegra241_vintf_free_lvcmdq() since
devres will take care of that.

Fixes: 483e0bd8883a ("iommu/tegra241-cmdqv: Do not allocate vcmdq until dma_set_mask_and_coherent")
Cc: stable@vger.kernel.org
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20250407201908.172225-1-nicolinc@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

0 files changed, 0 insertions, 0 deletions