Re: [PATCH v7 11/12] vduse: Introduce VDUSE - vDPA Device in Userspace
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From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-05-31 04:56:32
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kvm, linux-fsdevel, linux-iommu, lkml, virtualization
On Mon, May 17, 2021 at 05:55:12PM +0800, Xie Yongji wrote:
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+struct vduse_dev { + struct vduse_vdpa *vdev; + struct device dev; + struct cdev cdev;
You now have 2 reference counted devices controling the lifespace of a single structure. A mess that is guaranteed to go wrong. Please never do this.
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+ struct vduse_virtqueue *vqs; + struct vduse_iova_domain *domain; + char *name; + struct mutex lock; + spinlock_t msg_lock; + atomic64_t msg_unique;
Why do you need an atomic and a lock?
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+ wait_queue_head_t waitq; + struct list_head send_list; + struct list_head recv_list; + struct list_head list; + struct vdpa_callback config_cb; + struct work_struct inject; + spinlock_t irq_lock; + unsigned long api_version; + bool connected; + int minor; + u16 vq_size_max; + u32 vq_num; + u32 vq_align; + u32 config_size; + u32 device_id; + u32 vendor_id; +}; + +struct vduse_dev_msg { + struct vduse_dev_request req; + struct vduse_dev_response resp; + struct list_head list; + wait_queue_head_t waitq; + bool completed; +}; + +struct vduse_control { + unsigned long api_version;
u64?
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+}; + +static unsigned long max_bounce_size = (64 * 1024 * 1024); +module_param(max_bounce_size, ulong, 0444); +MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)"); + +static unsigned long max_iova_size = (128 * 1024 * 1024); +module_param(max_iova_size, ulong, 0444); +MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)"); + +static bool allow_unsafe_device_emulation; +module_param(allow_unsafe_device_emulation, bool, 0444); +MODULE_PARM_DESC(allow_unsafe_device_emulation, "Allow emulating unsafe device." + " We must make sure the userspace device emulation process is trusted." + " Otherwise, don't enable this option. (default: false)"); +
This is not the 1990's anymore, please never use module parameters, make these per-device attributes if you really need them.
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+static int vduse_init(void) +{ + int ret; + + if (max_bounce_size >= max_iova_size) + return -EINVAL; + + ret = misc_register(&vduse_misc); + if (ret) + return ret; + + vduse_class = class_create(THIS_MODULE, "vduse");
If you have a misc device, you do not need to create a class at the same time. Why are you doing both here? Just stick with the misc device, no need for anything else.
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+ if (IS_ERR(vduse_class)) { + ret = PTR_ERR(vduse_class); + goto err_class; + } + vduse_class->devnode = vduse_devnode; + + ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
Wait, you want a whole major? What is the misc device for?
+MODULE_VERSION(DRV_VERSION);
MODULE_VERSION() makes no sense when the code is merged into the kernel tree, so you can just drop that. thanks, greg k-h