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

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commit 767e22001dfce64cc03b7def1562338591ab6031 upstream.

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 ]------------
 128 pages are still in use!
 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: 483e0bd888 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicolin Chen
2025-04-07 13:19:08 -07:00
committed by Greg Kroah-Hartman
parent b8b41eac70
commit e5dd974d6e
1 changed files with 5 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
View File

@@ -487,17 +487,6 @@ static int tegra241_cmdqv_hw_reset(struct arm_smmu_device *smmu)
/* VCMDQ Resource Helpers */
static void tegra241_vcmdq_free_smmu_cmdq(struct tegra241_vcmdq *vcmdq)
{
struct arm_smmu_queue *q = &vcmdq->cmdq.q;
size_t nents = 1 << q->llq.max_n_shift;
size_t qsz = nents << CMDQ_ENT_SZ_SHIFT;
if (!q->base)
return;
dmam_free_coherent(vcmdq->cmdqv->smmu.dev, qsz, q->base, q->base_dma);
}
static int tegra241_vcmdq_alloc_smmu_cmdq(struct tegra241_vcmdq *vcmdq)
{
struct arm_smmu_device *smmu = &vcmdq->cmdqv->smmu;
@@ -560,7 +549,8 @@ static void tegra241_vintf_free_lvcmdq(struct tegra241_vintf *vintf, u16 lidx)
struct tegra241_vcmdq *vcmdq = vintf->lvcmdqs[lidx];
char header[64];
tegra241_vcmdq_free_smmu_cmdq(vcmdq);
/* Note that the lvcmdq queue memory space is managed by devres */
tegra241_vintf_deinit_lvcmdq(vintf, lidx);
dev_dbg(vintf->cmdqv->dev,
@@ -768,13 +758,13 @@ static int tegra241_cmdqv_init_structures(struct arm_smmu_device *smmu)
vintf = kzalloc(sizeof(*vintf), GFP_KERNEL);
if (!vintf)
goto out_fallback;
return -ENOMEM;
/* Init VINTF0 for in-kernel use */
ret = tegra241_cmdqv_init_vintf(cmdqv, 0, vintf);
if (ret) {
dev_err(cmdqv->dev, "failed to init vintf0: %d\n", ret);
goto free_vintf;
return ret;
}
/* Preallocate logical VCMDQs to VINTF0 */
@@ -783,24 +773,12 @@ static int tegra241_cmdqv_init_structures(struct arm_smmu_device *smmu)
vcmdq = tegra241_vintf_alloc_lvcmdq(vintf, lidx);
if (IS_ERR(vcmdq))
goto free_lvcmdq;
return PTR_ERR(vcmdq);
}
/* Now, we are ready to run all the impl ops */
smmu->impl_ops = &tegra241_cmdqv_impl_ops;
return 0;
free_lvcmdq:
for (lidx--; lidx >= 0; lidx--)
tegra241_vintf_free_lvcmdq(vintf, lidx);
tegra241_cmdqv_deinit_vintf(cmdqv, vintf->idx);
free_vintf:
kfree(vintf);
out_fallback:
dev_info(smmu->impl_dev, "Falling back to standard SMMU CMDQ\n");
smmu->options &= ~ARM_SMMU_OPT_TEGRA241_CMDQV;
tegra241_cmdqv_remove(smmu);
return 0;
}
#ifdef CONFIG_IOMMU_DEBUGFS