From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org
Cc: fenghua.yu@intel.com,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
catalin.marinas@arm.com, robin.murphy@arm.com,
zhengxiang9@huawei.com, zhangfei.gao@linaro.org, will@kernel.org
Subject: [PATCH RESEND v9 02/13] iommu/ioasid: Add ioasid references
Date: Mon, 17 Aug 2020 19:15:48 +0200 [thread overview]
Message-ID: <20200817171558.325917-3-jean-philippe@linaro.org> (raw)
In-Reply-To: <20200817171558.325917-1-jean-philippe@linaro.org>
Let IOASID users take references to existing ioasids with ioasid_get().
ioasid_put() drops a reference and only frees the ioasid when its
reference number is zero. It returns true if the ioasid was freed.
For drivers that don't call ioasid_get(), ioasid_put() is the same as
ioasid_free().
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
include/linux/ioasid.h | 10 ++++++++--
drivers/iommu/intel/iommu.c | 4 ++--
drivers/iommu/intel/svm.c | 6 +++---
drivers/iommu/ioasid.c | 38 +++++++++++++++++++++++++++++++++----
4 files changed, 47 insertions(+), 11 deletions(-)
diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
index 6f000d7a0ddc..e9dacd4b9f6b 100644
--- a/include/linux/ioasid.h
+++ b/include/linux/ioasid.h
@@ -34,7 +34,8 @@ struct ioasid_allocator_ops {
#if IS_ENABLED(CONFIG_IOASID)
ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
void *private);
-void ioasid_free(ioasid_t ioasid);
+void ioasid_get(ioasid_t ioasid);
+bool ioasid_put(ioasid_t ioasid);
void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
bool (*getter)(void *));
int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
@@ -48,10 +49,15 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min,
return INVALID_IOASID;
}
-static inline void ioasid_free(ioasid_t ioasid)
+static inline void ioasid_get(ioasid_t ioasid)
{
}
+static inline bool ioasid_put(ioasid_t ioasid)
+{
+ return false;
+}
+
static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
bool (*getter)(void *))
{
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index e9864e52b0e9..152fc2dc17e0 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5149,7 +5149,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
domain->auxd_refcnt--;
if (!domain->auxd_refcnt && domain->default_pasid > 0)
- ioasid_free(domain->default_pasid);
+ ioasid_put(domain->default_pasid);
}
static int aux_domain_add_dev(struct dmar_domain *domain,
@@ -5210,7 +5210,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
spin_unlock(&iommu->lock);
spin_unlock_irqrestore(&device_domain_lock, flags);
if (!domain->auxd_refcnt && domain->default_pasid > 0)
- ioasid_free(domain->default_pasid);
+ ioasid_put(domain->default_pasid);
return ret;
}
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 95c3164a2302..50897a2bd1da 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -565,7 +565,7 @@ intel_svm_bind_mm(struct device *dev, int flags, struct svm_dev_ops *ops,
if (mm) {
ret = mmu_notifier_register(&svm->notifier, mm);
if (ret) {
- ioasid_free(svm->pasid);
+ ioasid_put(svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
@@ -583,7 +583,7 @@ intel_svm_bind_mm(struct device *dev, int flags, struct svm_dev_ops *ops,
if (ret) {
if (mm)
mmu_notifier_unregister(&svm->notifier, mm);
- ioasid_free(svm->pasid);
+ ioasid_put(svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
@@ -652,7 +652,7 @@ static int intel_svm_unbind_mm(struct device *dev, int pasid)
kfree_rcu(sdev, rcu);
if (list_empty(&svm->devs)) {
- ioasid_free(svm->pasid);
+ ioasid_put(svm->pasid);
if (svm->mm)
mmu_notifier_unregister(&svm->notifier, svm->mm);
list_del(&svm->list);
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
index 0f8dd377aada..50ee27bbd04e 100644
--- a/drivers/iommu/ioasid.c
+++ b/drivers/iommu/ioasid.c
@@ -2,7 +2,7 @@
/*
* I/O Address Space ID allocator. There is one global IOASID space, split into
* subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and
- * free IOASIDs with ioasid_alloc and ioasid_free.
+ * free IOASIDs with ioasid_alloc and ioasid_put.
*/
#include <linux/ioasid.h>
#include <linux/module.h>
@@ -15,6 +15,7 @@ struct ioasid_data {
struct ioasid_set *set;
void *private;
struct rcu_head rcu;
+ refcount_t refs;
};
/*
@@ -314,6 +315,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
data->set = set;
data->private = private;
+ refcount_set(&data->refs, 1);
/*
* Custom allocator needs allocator data to perform platform specific
@@ -346,11 +348,34 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
EXPORT_SYMBOL_GPL(ioasid_alloc);
/**
- * ioasid_free - Free an IOASID
+ * ioasid_get - obtain a reference to the IOASID
+ */
+void ioasid_get(ioasid_t ioasid)
+{
+ struct ioasid_data *ioasid_data;
+
+ spin_lock(&ioasid_allocator_lock);
+ ioasid_data = xa_load(&active_allocator->xa, ioasid);
+ if (ioasid_data)
+ refcount_inc(&ioasid_data->refs);
+ else
+ WARN_ON(1);
+ spin_unlock(&ioasid_allocator_lock);
+}
+EXPORT_SYMBOL_GPL(ioasid_get);
+
+/**
+ * ioasid_put - Release a reference to an ioasid
* @ioasid: the ID to remove
+ *
+ * Put a reference to the IOASID, free it when the number of references drops to
+ * zero.
+ *
+ * Return: %true if the IOASID was freed, %false otherwise.
*/
-void ioasid_free(ioasid_t ioasid)
+bool ioasid_put(ioasid_t ioasid)
{
+ bool free = false;
struct ioasid_data *ioasid_data;
spin_lock(&ioasid_allocator_lock);
@@ -360,6 +385,10 @@ void ioasid_free(ioasid_t ioasid)
goto exit_unlock;
}
+ free = refcount_dec_and_test(&ioasid_data->refs);
+ if (!free)
+ goto exit_unlock;
+
active_allocator->ops->free(ioasid, active_allocator->ops->pdata);
/* Custom allocator needs additional steps to free the xa element */
if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) {
@@ -369,8 +398,9 @@ void ioasid_free(ioasid_t ioasid)
exit_unlock:
spin_unlock(&ioasid_allocator_lock);
+ return free;
}
-EXPORT_SYMBOL_GPL(ioasid_free);
+EXPORT_SYMBOL_GPL(ioasid_put);
/**
* ioasid_find - Find IOASID data
--
2.28.0
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next prev parent reply other threads:[~2020-08-17 17:18 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-17 17:15 [PATCH RESEND v9 00/13] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part) Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 01/13] mm: Define pasid in mm Jean-Philippe Brucker
2020-08-17 17:15 ` Jean-Philippe Brucker [this message]
2020-09-08 9:52 ` [PATCH RESEND v9 02/13] iommu/ioasid: Add ioasid references Auger Eric
2020-08-17 17:15 ` [PATCH RESEND v9 03/13] iommu/sva: Add PASID helpers Jean-Philippe Brucker
2020-09-08 7:45 ` Auger Eric
2020-09-17 14:36 ` Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 04/13] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 05/13] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 06/13] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 07/13] iommu/arm-smmu-v3: Move definitions to a header Jean-Philippe Brucker
2020-09-08 9:16 ` Auger Eric
2020-08-17 17:15 ` [PATCH RESEND v9 08/13] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-09-08 7:41 ` Auger Eric
2020-09-17 14:37 ` Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 09/13] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-09-07 16:41 ` Auger Eric
2020-09-17 14:38 ` Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 10/13] iommu/arm-smmu-v3: Check for SVA features Jean-Philippe Brucker
2020-09-08 9:38 ` Auger Eric
2020-09-17 14:39 ` Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 11/13] iommu/arm-smmu-v3: Add SVA device feature Jean-Philippe Brucker
2020-09-08 9:46 ` Auger Eric
2020-09-17 14:40 ` Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 12/13] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() Jean-Philippe Brucker
2020-08-17 17:15 ` [PATCH RESEND v9 13/13] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-09-04 9:08 ` [PATCH RESEND v9 00/13] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part) Joerg Roedel
2020-09-17 14:36 ` Jean-Philippe Brucker
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