iommu/vt-d: Remove pasid_mutex

The pasid_mutex was used to protect the paths of set/remove_dev_pasid().
It's duplicate with iommu_sva_lock. Remove it to avoid duplicate code.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230802212427.1497170-5-jacob.jun.pan@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index e95b339e9cdc08fad49c4080a7bac48894fd65e3..2a82864e9d5784edce0de7e3f247d2f815ddb236 100644 (file)
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -259,8 +259,6 @@ static const struct mmu_notifier_ops intel_mmuops = {
        .invalidate_range = intel_invalidate_range,
 };
 
-static DEFINE_MUTEX(pasid_mutex);
-
 static int pasid_to_svm_sdev(struct device *dev, unsigned int pasid,
                             struct intel_svm **rsvm,
                             struct intel_svm_dev **rsdev)
@@ -268,10 +266,6 @@ static int pasid_to_svm_sdev(struct device *dev, unsigned int pasid,
        struct intel_svm_dev *sdev = NULL;
        struct intel_svm *svm;
 
-       /* The caller should hold the pasid_mutex lock */
-       if (WARN_ON(!mutex_is_locked(&pasid_mutex)))
-               return -EINVAL;
-
        if (pasid == IOMMU_PASID_INVALID || pasid >= PASID_MAX)
                return -EINVAL;
 
@@ -371,22 +365,19 @@ free_svm:
        return ret;
 }
 
-/* Caller must hold pasid_mutex */
-static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
+void intel_svm_remove_dev_pasid(struct device *dev, u32 pasid)
 {
        struct intel_svm_dev *sdev;
        struct intel_iommu *iommu;
        struct intel_svm *svm;
        struct mm_struct *mm;
-       int ret = -EINVAL;
 
        iommu = device_to_iommu(dev, NULL, NULL);
        if (!iommu)
-               goto out;
+               return;
 
-       ret = pasid_to_svm_sdev(dev, pasid, &svm, &sdev);
-       if (ret)
-               goto out;
+       if (pasid_to_svm_sdev(dev, pasid, &svm, &sdev))
+               return;
        mm = svm->mm;
 
        if (sdev) {
@@ -418,8 +409,6 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
                        kfree(svm);
                }
        }
-out:
-       return ret;
 }
 
 /* Page request queue descriptor */
@@ -520,19 +509,7 @@ prq_retry:
                goto prq_retry;
        }
 
-       /*
-        * A work in IO page fault workqueue may try to lock pasid_mutex now.
-        * Holding pasid_mutex while waiting in iopf_queue_flush_dev() for
-        * all works in the workqueue to finish may cause deadlock.
-        *
-        * It's unnecessary to hold pasid_mutex in iopf_queue_flush_dev().
-        * Unlock it to allow the works to be handled while waiting for
-        * them to finish.
-        */
-       lockdep_assert_held(&pasid_mutex);
-       mutex_unlock(&pasid_mutex);
        iopf_queue_flush_dev(dev);
-       mutex_lock(&pasid_mutex);
 
        /*
         * Perform steps described in VT-d spec CH7.10 to drain page
@@ -827,26 +804,14 @@ out:
        return ret;
 }
 
-void intel_svm_remove_dev_pasid(struct device *dev, ioasid_t pasid)
-{
-       mutex_lock(&pasid_mutex);
-       intel_svm_unbind_mm(dev, pasid);
-       mutex_unlock(&pasid_mutex);
-}
-
 static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
                                   struct device *dev, ioasid_t pasid)
 {
        struct device_domain_info *info = dev_iommu_priv_get(dev);
        struct intel_iommu *iommu = info->iommu;
        struct mm_struct *mm = domain->mm;
-       int ret;
 
-       mutex_lock(&pasid_mutex);
-       ret = intel_svm_bind_mm(iommu, dev, mm);
-       mutex_unlock(&pasid_mutex);
-
-       return ret;
+       return intel_svm_bind_mm(iommu, dev, mm);
 }
 
 static void intel_svm_domain_free(struct iommu_domain *domain)