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| author |   CQ Tang <cq.tang@intel.com> | 2017-05-10 11:39:03 -0700 |
|---|---|---|
| committer |   Joerg Roedel <jroedel@suse.de> | 2017-05-17 14:57:56 +0200 |
| commit | 15060aba717115dc9f204c02213a7c6bf341163e (patch) | |
| tree | 7ecaa7018f3cf6259a8b0344f63d727dbfccbab2 /include/linux/intel-svm.h | |
| parent | Linux 4.12-rc1 (diff) | |
| download | linux-dev-15060aba717115dc9f204c02213a7c6bf341163e.tar.xz linux-dev-15060aba717115dc9f204c02213a7c6bf341163e.zip | |
iommu/vt-d: Helper function to query if a pasid has any active users
A driver would need to know if there are any active references to a
a PASID before cleaning up its resources. This function helps check
if there are any active users of a PASID before it can perform any
recovery on that device.
To: Joerg Roedel <joro@8bytes.org>
To: linux-kernel@vger.kernel.org
To: David Woodhouse <dwmw2@infradead.org>
Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
Cc: iommu@lists.linux-foundation.org
Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'include/linux/intel-svm.h')
| -rw-r--r-- | include/linux/intel-svm.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h index 3c25794042f9..99bc5b3ae26e 100644 --- a/include/linux/intel-svm.h +++ b/include/linux/intel-svm.h @@ -102,6 +102,21 @@ extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, */ extern int intel_svm_unbind_mm(struct device *dev, int pasid); +/** + * intel_svm_is_pasid_valid() - check if pasid is valid + * @dev: Device for which PASID was allocated + * @pasid: PASID value to be checked + * + * This function checks if the specified pasid is still valid. A + * valid pasid means the backing mm is still having a valid user. + * For kernel callers init_mm is always valid. for other mm, if mm->mm_users + * is non-zero, it is valid. + * + * returns -EINVAL if invalid pasid, 0 if pasid ref count is invalid + * 1 if pasid is valid. + */ +extern int intel_svm_is_pasid_valid(struct device *dev, int pasid); + #else /* CONFIG_INTEL_IOMMU_SVM */ static inline int intel_svm_bind_mm(struct device *dev, int *pasid, @@ -114,6 +129,11 @@ static inline int intel_svm_unbind_mm(struct device *dev, int pasid) { BUG(); } + +static int intel_svm_is_pasid_valid(struct device *dev, int pasid) +{ + return -EINVAL; +} #endif /* CONFIG_INTEL_IOMMU_SVM */ #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) |