Messages in this thread Patch in this message |  | | From | Nicolin Chen <> | Subject | [PATCH v2 2/3] iommufd/device: Make hwpt_list list_add/del symmetric | Date | Sat, 28 Jan 2023 13:18:10 -0800 |
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Since the list_del() of hwpt_item is done in iommufd_device_detach(), move its list_add_tail() to a similar place in iommufd_device_do_attach().
Also move and place the mutex outside the iommufd_device_auto_get_domain() and iommufd_device_do_attach() calls, to serialize attach/detach routines. This adds an additional locking protection so that the following patch can safely remove devices_lock.
Co-developed-by: Yi Liu <yi.l.liu@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> --- drivers/iommu/iommufd/device.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 208757c39c90..9375fcac884c 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -198,6 +198,8 @@ static int iommufd_device_do_attach(struct iommufd_device *idev, phys_addr_t sw_msi_start = PHYS_ADDR_MAX; int rc; + lockdep_assert_held(&hwpt->ioas->mutex); + mutex_lock(&hwpt->devices_lock); /* @@ -241,6 +243,7 @@ static int iommufd_device_do_attach(struct iommufd_device *idev, hwpt->domain); if (rc) goto out_detach; + list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list); } } @@ -271,12 +274,13 @@ static int iommufd_device_auto_get_domain(struct iommufd_device *idev, struct iommufd_hw_pagetable *hwpt; int rc; + lockdep_assert_held(&ioas->mutex); + /* * There is no differentiation when domains are allocated, so any domain * that is willing to attach to the device is interchangeable with any * other. */ - mutex_lock(&ioas->mutex); list_for_each_entry(hwpt, &ioas->hwpt_list, hwpt_item) { if (!hwpt->auto_domain) continue; @@ -290,29 +294,23 @@ static int iommufd_device_auto_get_domain(struct iommufd_device *idev, */ if (rc == -EINVAL) continue; - goto out_unlock; + return rc; } hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev->dev); - if (IS_ERR(hwpt)) { - rc = PTR_ERR(hwpt); - goto out_unlock; - } + if (IS_ERR(hwpt)) + return PTR_ERR(hwpt); hwpt->auto_domain = true; rc = iommufd_device_do_attach(idev, hwpt); if (rc) goto out_abort; - list_add_tail(&hwpt->hwpt_item, &ioas->hwpt_list); - mutex_unlock(&ioas->mutex); iommufd_object_finalize(idev->ictx, &hwpt->obj); return 0; out_abort: iommufd_object_abort_and_destroy(idev->ictx, &hwpt->obj); -out_unlock: - mutex_unlock(&ioas->mutex); return rc; } @@ -342,20 +340,20 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id) struct iommufd_hw_pagetable *hwpt = container_of(pt_obj, struct iommufd_hw_pagetable, obj); + mutex_lock(&hwpt->ioas->mutex); rc = iommufd_device_do_attach(idev, hwpt); + mutex_unlock(&hwpt->ioas->mutex); if (rc) goto out_put_pt_obj; - - mutex_lock(&hwpt->ioas->mutex); - list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list); - mutex_unlock(&hwpt->ioas->mutex); break; } case IOMMUFD_OBJ_IOAS: { struct iommufd_ioas *ioas = container_of(pt_obj, struct iommufd_ioas, obj); + mutex_lock(&ioas->mutex); rc = iommufd_device_auto_get_domain(idev, ioas); + mutex_unlock(&ioas->mutex); if (rc) goto out_put_pt_obj; break; -- 2.39.1
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