From c0d498a1b99d5417f19c35ecd98ac0ff73c351a4 Mon Sep 17 00:00:00 2001 From: Nicolin Chen Date: Fri, 13 Jun 2025 23:35:25 -0700 Subject: [PATCH] iommufd: Introduce iommufd_object_alloc_ucmd helper An object allocator needs to call either iommufd_object_finalize() upon a success or iommufd_object_abort_and_destroy() upon an error code. To reduce duplication, store a new_obj in the struct iommufd_ucmd and call iommufd_object_finalize/iommufd_object_abort_and_destroy() accordingly in the main function. Similar to iommufd_object_alloc() and __iommufd_object_alloc(), add a pair of helpers: __iommufd_object_alloc_ucmd() and iommufd_object_alloc_ucmd(). Link: https://patch.msgid.link/r/e7206d4227844887cc8dbf0cc7b0242580fafd9d.1749882255.git.nicolinc@nvidia.com Suggested-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Signed-off-by: Nicolin Chen Reviewed-by: Lu Baolu Acked-by: Pranjal Shrivastava Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommufd/iommufd_private.h | 26 +++++++++++++++++++++++++ drivers/iommu/iommufd/main.c | 25 ++++++++++++++++++++++++ 2 files changed, 51 insertions(+) diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index ec5b499d139cd..4f5e8cd99c965 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -135,6 +135,7 @@ struct iommufd_ucmd { void __user *ubuffer; u32 user_size; void *cmd; + struct iommufd_object *new_obj; }; int iommufd_vfio_ioctl(struct iommufd_ctx *ictx, unsigned int cmd, @@ -230,6 +231,11 @@ iommufd_object_put_and_try_destroy(struct iommufd_ctx *ictx, iommufd_object_remove(ictx, obj, obj->id, 0); } +/* + * Callers of these normal object allocators must call iommufd_object_finalize() + * to finalize the object, or call iommufd_object_abort_and_destroy() to revert + * the allocation. + */ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx, size_t size, enum iommufd_object_type type); @@ -246,6 +252,26 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx, #define iommufd_object_alloc(ictx, ptr, type) \ __iommufd_object_alloc(ictx, ptr, type, obj) +/* + * Callers of these _ucmd allocators should not call iommufd_object_finalize() + * or iommufd_object_abort_and_destroy(), as the core automatically does that. + */ +struct iommufd_object * +_iommufd_object_alloc_ucmd(struct iommufd_ucmd *ucmd, size_t size, + enum iommufd_object_type type); + +#define __iommufd_object_alloc_ucmd(ucmd, ptr, type, obj) \ + container_of(_iommufd_object_alloc_ucmd( \ + ucmd, \ + sizeof(*(ptr)) + BUILD_BUG_ON_ZERO( \ + offsetof(typeof(*(ptr)), \ + obj) != 0), \ + type), \ + typeof(*(ptr)), obj) + +#define iommufd_object_alloc_ucmd(ucmd, ptr, type) \ + __iommufd_object_alloc_ucmd(ucmd, ptr, type, obj) + /* * The IO Address Space (IOAS) pagetable is a virtual page table backed by the * io_pagetable object. It is a user controlled mapping of IOVA -> PFNs. The diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 85ad2853da0b7..778694d7c2075 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -61,6 +61,24 @@ out_free: return ERR_PTR(rc); } +struct iommufd_object *_iommufd_object_alloc_ucmd(struct iommufd_ucmd *ucmd, + size_t size, + enum iommufd_object_type type) +{ + struct iommufd_object *new_obj; + + /* Something is coded wrong if this is hit */ + if (WARN_ON(ucmd->new_obj)) + return ERR_PTR(-EBUSY); + + new_obj = _iommufd_object_alloc(ucmd->ictx, size, type); + if (IS_ERR(new_obj)) + return new_obj; + + ucmd->new_obj = new_obj; + return new_obj; +} + /* * Allow concurrent access to the object. * @@ -448,6 +466,13 @@ static long iommufd_fops_ioctl(struct file *filp, unsigned int cmd, if (ret) return ret; ret = op->execute(&ucmd); + + if (ucmd.new_obj) { + if (ret) + iommufd_object_abort_and_destroy(ictx, ucmd.new_obj); + else + iommufd_object_finalize(ictx, ucmd.new_obj); + } return ret; } -- 2.47.2