From: Jason Gunthorpe Date: Mon, 16 May 2022 20:41:19 -0300 Subject: vfio: Split up vfio_group_get_device_fd() Git-commit: 805bb6c1bd9009e389f884fa30ec5f5e5079376d Patch-mainline: v5.19-rc1 References: bsc#1205701 The split follows the pairing with the destroy functions: - vfio_group_get_device_fd() destroyed by close() - vfio_device_open() destroyed by vfio_device_fops_release() - vfio_device_assign_container() destroyed by vfio_group_try_dissolve_container() The next patch will put a lock around vfio_device_assign_container(). Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe Tested-by: Nicolin Chen Tested-by: Matthew Rosato Link: https://lore.kernel.org/r/3-v2-d035a1842d81+1bf-vfio_group_locking_jgg@nvidia.com Signed-off-by: Alex Williamson Acked-by: Joerg Roedel --- drivers/vfio/vfio.c | 79 +++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 56 insertions(+), 23 deletions(-) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 12d4b3efd463..21db0e8d0d40 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1064,12 +1064,9 @@ static bool vfio_assert_device_open(struct vfio_device *device) return !WARN_ON_ONCE(!READ_ONCE(device->open_count)); } -static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) +static int vfio_device_assign_container(struct vfio_device *device) { - struct vfio_device *device; - struct file *filep; - int fdno; - int ret = 0; + struct vfio_group *group = device->group; if (0 == atomic_read(&group->container_users) || !group->container->iommu_driver) @@ -1078,13 +1075,22 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) return -EPERM; - device = vfio_device_get_from_name(group, buf); - if (IS_ERR(device)) - return PTR_ERR(device); + atomic_inc(&group->container_users); + return 0; +} + +static struct file *vfio_device_open(struct vfio_device *device) +{ + struct file *filep; + int ret; + + ret = vfio_device_assign_container(device); + if (ret) + return ERR_PTR(ret); if (!try_module_get(device->dev->driver->owner)) { ret = -ENODEV; - goto err_device_put; + goto err_unassign_container; } mutex_lock(&device->dev_set->lock); @@ -1100,15 +1106,11 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) * We can't use anon_inode_getfd() because we need to modify * the f_mode flags directly to allow more than just ioctls */ - fdno = ret = get_unused_fd_flags(O_CLOEXEC); - if (ret < 0) - goto err_close_device; - filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops, device, O_RDWR); if (IS_ERR(filep)) { ret = PTR_ERR(filep); - goto err_fd; + goto err_close_device; } /* @@ -1118,17 +1120,15 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) */ filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); - atomic_inc(&group->container_users); - - fd_install(fdno, filep); - - if (group->type == VFIO_NO_IOMMU) + if (device->group->type == VFIO_NO_IOMMU) dev_warn(device->dev, "vfio-noiommu device opened by user " "(%s:%d)\n", current->comm, task_pid_nr(current)); - return fdno; + /* + * On success the ref of device is moved to the file and + * put in vfio_device_fops_release() + */ + return filep; -err_fd: - put_unused_fd(fdno); err_close_device: mutex_lock(&device->dev_set->lock); if (device->open_count == 1 && device->ops->close_device) @@ -1137,7 +1137,40 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) device->open_count--; mutex_unlock(&device->dev_set->lock); module_put(device->dev->driver->owner); -err_device_put: +err_unassign_container: + vfio_group_try_dissolve_container(device->group); + return ERR_PTR(ret); +} + +static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) +{ + struct vfio_device *device; + struct file *filep; + int fdno; + int ret; + + device = vfio_device_get_from_name(group, buf); + if (IS_ERR(device)) + return PTR_ERR(device); + + fdno = get_unused_fd_flags(O_CLOEXEC); + if (fdno < 0) { + ret = fdno; + goto err_put_device; + } + + filep = vfio_device_open(device); + if (IS_ERR(filep)) { + ret = PTR_ERR(filep); + goto err_put_fdno; + } + + fd_install(fdno, filep); + return fdno; + +err_put_fdno: + put_unused_fd(fdno); +err_put_device: vfio_device_put(device); return ret; }