drivers/iommu/iommufd/driver.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES
   3  */
   4 #include "iommufd_private.h"
   5
   6 struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
   7                                              size_t size,
   8                                              enum iommufd_object_type type)
   9 {
  10         struct iommufd_object *obj;
  11         int rc;
  12
  13         obj = kzalloc(size, GFP_KERNEL_ACCOUNT);
  14         if (!obj)
  15                 return ERR_PTR(-ENOMEM);
  16         obj->type = type;
  17         /* Starts out bias'd by 1 until it is removed from the xarray */
  18         refcount_set(&obj->shortterm_users, 1);
  19         refcount_set(&obj->users, 1);
  20
  21         /*
  22          * Reserve an ID in the xarray but do not publish the pointer yet since
  23          * the caller hasn't initialized it yet. Once the pointer is published
  24          * in the xarray and visible to other threads we can't reliably destroy
  25          * it anymore, so the caller must complete all errorable operations
  26          * before calling iommufd_object_finalize().
  27          */
  28         rc = xa_alloc(&ictx->objects, &obj->id, XA_ZERO_ENTRY, xa_limit_31b,
  29                       GFP_KERNEL_ACCOUNT);
  30         if (rc)
  31                 goto out_free;
  32         return obj;
  33 out_free:
  34         kfree(obj);
  35         return ERR_PTR(rc);
  36 }
  37 EXPORT_SYMBOL_NS_GPL(_iommufd_object_alloc, "IOMMUFD");
  38
  39 /* Caller should xa_lock(&viommu->vdevs) to protect the return value */
  40 struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
  41                                        unsigned long vdev_id)
  42 {
  43         struct iommufd_vdevice *vdev;
  44
  45         lockdep_assert_held(&viommu->vdevs.xa_lock);
  46
  47         vdev = xa_load(&viommu->vdevs, vdev_id);
  48         return vdev ? vdev->dev : NULL;
  49 }
  50 EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, "IOMMUFD");
  51
  52 MODULE_DESCRIPTION("iommufd code shared with builtin modules");
  53 MODULE_LICENSE("GPL");