[PATCH v4 09/27] iommu/arm-smmu-v3: Allocate the CD table entry in advance
From: Jason Gunthorpe <jgg@nvidia.com>
Date: 2024-01-26 18:16:31
Also in:
linux-iommu, linux-patches
Subsystem:
arm smmu drivers, iommu subsystem, the rest · Maintainers:
Will Deacon, Joerg Roedel, Linus Torvalds
Avoid arm_smmu_attach_dev() having to undo the changes to the smmu_domain->devices list, acquire the cdptr earlier so we don't need to handle that error. Now there is a clear break in arm_smmu_attach_dev() where all the prep-work has been done non-disruptively and we commit to making the HW change, which cannot fail. This completes transforming arm_smmu_attach_dev() so that it does not disturb the HW if it fails. Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 24 +++++++-------------- 1 file changed, 8 insertions(+), 16 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 7562d7577f3940..79d80de4c0a60f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c@@ -2665,6 +2665,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) struct arm_smmu_device *smmu; struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); struct arm_smmu_master *master; + struct arm_smmu_cd *cdptr; if (!fwspec) return -ENOENT;
@@ -2693,6 +2694,12 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) if (ret) return ret; + if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) { + cdptr = arm_smmu_get_cd_ptr(master, IOMMU_NO_PASID); + if (!cdptr) + return -ENOMEM; + } + /* * Prevent arm_smmu_share_asid() from trying to change the ASID * of either the old or new domain while we are working on it.
@@ -2712,13 +2719,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) switch (smmu_domain->stage) { case ARM_SMMU_DOMAIN_S1: { struct arm_smmu_cd target_cd; - struct arm_smmu_cd *cdptr; - - cdptr = arm_smmu_get_cd_ptr(master, IOMMU_NO_PASID); - if (!cdptr) { - ret = -ENOMEM; - goto out_list_del; - } arm_smmu_make_s1_cd(&target_cd, master, smmu_domain); arm_smmu_write_cd_entry(master, IOMMU_NO_PASID, cdptr,
@@ -2735,16 +2735,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) } arm_smmu_enable_ats(master, smmu_domain); - goto out_unlock; - -out_list_del: - spin_lock_irqsave(&smmu_domain->devices_lock, flags); - list_del_init(&master->domain_head); - spin_unlock_irqrestore(&smmu_domain->devices_lock, flags); - -out_unlock: mutex_unlock(&arm_smmu_asid_lock); - return ret; + return 0; } static int arm_smmu_attach_dev_ste(struct device *dev,
--
2.43.0
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