From bf8aff2945ba4091f503df673b9df33002546e6a Mon Sep 17 00:00:00 2001 From: Vasant Hegde Date: Mon, 5 Feb 2024 11:56:07 +0000 Subject: [PATCH] iommu: Introduce iommu_group_mutex_assert() Add function to check iommu group mutex lock. So that device drivers can rely on group mutex lock instead of adding another driver level lock before modifying driver specific device data structure. Suggested-by: Jason Gunthorpe Signed-off-by: Vasant Hegde Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20240205115615.6053-10-vasant.hegde@amd.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 19 +++++++++++++++++++ include/linux/iommu.h | 8 ++++++++ 2 files changed, 27 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index d14413916f93a..8309e634977e2 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -1248,6 +1248,25 @@ void iommu_group_remove_device(struct device *dev) } EXPORT_SYMBOL_GPL(iommu_group_remove_device); +#if IS_ENABLED(CONFIG_LOCKDEP) && IS_ENABLED(CONFIG_IOMMU_API) +/** + * iommu_group_mutex_assert - Check device group mutex lock + * @dev: the device that has group param set + * + * This function is called by an iommu driver to check whether it holds + * group mutex lock for the given device or not. + * + * Note that this function must be called after device group param is set. + */ +void iommu_group_mutex_assert(struct device *dev) +{ + struct iommu_group *group = dev->iommu_group; + + lockdep_assert_held(&group->mutex); +} +EXPORT_SYMBOL_GPL(iommu_group_mutex_assert); +#endif + static struct device *iommu_group_first_dev(struct iommu_group *group) { lockdep_assert_held(&group->mutex); diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 32bb121e8032c..8141a37556d5f 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -1356,6 +1356,14 @@ static inline ioasid_t iommu_alloc_global_pasid(struct device *dev) static inline void iommu_free_global_pasid(ioasid_t pasid) {} #endif /* CONFIG_IOMMU_API */ +#if IS_ENABLED(CONFIG_LOCKDEP) && IS_ENABLED(CONFIG_IOMMU_API) +void iommu_group_mutex_assert(struct device *dev); +#else +static inline void iommu_group_mutex_assert(struct device *dev) +{ +} +#endif + /** * iommu_map_sgtable - Map the given buffer to the IOMMU domain * @domain: The IOMMU domain to perform the mapping -- 2.30.2