diff options
Diffstat (limited to 'drivers/iommu/iommufd/main.c')
| -rw-r--r-- | drivers/iommu/iommufd/main.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 649fe79d0f0c..6add737a6708 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -23,6 +23,7 @@ #include "iommufd_test.h" struct iommufd_object_ops { + size_t file_offset; void (*destroy)(struct iommufd_object *obj); void (*abort)(struct iommufd_object *obj); }; @@ -97,10 +98,30 @@ void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj) void iommufd_object_abort_and_destroy(struct iommufd_ctx *ictx, struct iommufd_object *obj) { - if (iommufd_object_ops[obj->type].abort) - iommufd_object_ops[obj->type].abort(obj); + const struct iommufd_object_ops *ops = &iommufd_object_ops[obj->type]; + + if (ops->file_offset) { + struct file **filep = ((void *)obj) + ops->file_offset; + + /* + * A file should hold a users refcount while the file is open + * and put it back in its release. The file should hold a + * pointer to obj in their private data. Normal fput() is + * deferred to a workqueue and can get out of order with the + * following kfree(obj). Using the sync version ensures the + * release happens immediately. During abort we require the file + * refcount is one at this point - meaning the object alloc + * function cannot do anything to allow another thread to take a + * refcount prior to a guaranteed success. + */ + if (*filep) + __fput_sync(*filep); + } + + if (ops->abort) + ops->abort(obj); else - iommufd_object_ops[obj->type].destroy(obj); + ops->destroy(obj); iommufd_object_abort(ictx, obj); } @@ -498,6 +519,12 @@ void iommufd_ctx_put(struct iommufd_ctx *ictx) } EXPORT_SYMBOL_NS_GPL(iommufd_ctx_put, IOMMUFD); +#define IOMMUFD_FILE_OFFSET(_struct, _filep, _obj) \ + .file_offset = (offsetof(_struct, _filep) + \ + BUILD_BUG_ON_ZERO(!__same_type( \ + struct file *, ((_struct *)NULL)->_filep)) + \ + BUILD_BUG_ON_ZERO(offsetof(_struct, _obj))) + static const struct iommufd_object_ops iommufd_object_ops[] = { [IOMMUFD_OBJ_ACCESS] = { .destroy = iommufd_access_destroy_object, @@ -518,6 +545,7 @@ static const struct iommufd_object_ops iommufd_object_ops[] = { }, [IOMMUFD_OBJ_FAULT] = { .destroy = iommufd_fault_destroy, + IOMMUFD_FILE_OFFSET(struct iommufd_fault, filep, obj), }, #ifdef CONFIG_IOMMUFD_TEST [IOMMUFD_OBJ_SELFTEST] = { |