// SPDX-License-Identifier: GPL-2.0-only /* * The Virtio 9p transport driver * * This is a block based transport driver based on the lguest block driver * code. * * Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation * * Based on virtio console driver * Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation */ #define pr_fmt(fmt) … #include <linux/in.h> #include <linux/module.h> #include <linux/net.h> #include <linux/ipv6.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/un.h> #include <linux/uaccess.h> #include <linux/inet.h> #include <linux/file.h> #include <linux/highmem.h> #include <linux/slab.h> #include <net/9p/9p.h> #include <linux/parser.h> #include <net/9p/client.h> #include <net/9p/transport.h> #include <linux/scatterlist.h> #include <linux/swap.h> #include <linux/virtio.h> #include <linux/virtio_9p.h> #include "trans_common.h" #define VIRTQUEUE_NUM … /* a single mutex to manage channel initialization and attachment */ static DEFINE_MUTEX(virtio_9p_lock); static DECLARE_WAIT_QUEUE_HEAD(vp_wq); static atomic_t vp_pinned = …; /** * struct virtio_chan - per-instance transport information * @inuse: whether the channel is in use * @lock: protects multiple elements within this structure * @client: client instance * @vdev: virtio dev associated with this channel * @vq: virtio queue associated with this channel * @ring_bufs_avail: flag to indicate there is some available in the ring buf * @vc_wq: wait queue for waiting for thing to be added to ring buf * @p9_max_pages: maximum number of pinned pages * @sg: scatter gather list which is used to pack a request (protected?) * @chan_list: linked list of channels * * We keep all per-channel information in a structure. * This structure is allocated within the devices dev->mem space. * A pointer to the structure will get put in the transport private. * */ struct virtio_chan { … }; static struct list_head virtio_chan_list; /* How many bytes left in this page. */ static unsigned int rest_of_page(void *data) { … } /** * p9_virtio_close - reclaim resources of a channel * @client: client instance * * This reclaims a channel by freeing its resources and * resetting its inuse flag. * */ static void p9_virtio_close(struct p9_client *client) { … } /** * req_done - callback which signals activity from the server * @vq: virtio queue activity was received on * * This notifies us that the server has triggered some activity * on the virtio channel - most likely a response to request we * sent. Figure out which requests now have responses and wake up * those threads. * * Bugs: could do with some additional sanity checking, but appears to work. * */ static void req_done(struct virtqueue *vq) { … } /** * pack_sg_list - pack a scatter gather list from a linear buffer * @sg: scatter/gather list to pack into * @start: which segment of the sg_list to start at * @limit: maximum segment to pack data to * @data: data to pack into scatter/gather list * @count: amount of data to pack into the scatter/gather list * * sg_lists have multiple segments of various sizes. This will pack * arbitrary data into an existing scatter gather list, segmenting the * data as necessary within constraints. * */ static int pack_sg_list(struct scatterlist *sg, int start, int limit, char *data, int count) { … } /* We don't currently allow canceling of virtio requests */ static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) { … } /* Reply won't come, so drop req ref */ static int p9_virtio_cancelled(struct p9_client *client, struct p9_req_t *req) { … } /** * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, * this takes a list of pages. * @sg: scatter/gather list to pack into * @start: which segment of the sg_list to start at * @limit: maximum number of pages in sg list. * @pdata: a list of pages to add into sg. * @nr_pages: number of pages to pack into the scatter/gather list * @offs: amount of data in the beginning of first page _not_ to pack * @count: amount of data to pack into the scatter/gather list */ static int pack_sg_list_p(struct scatterlist *sg, int start, int limit, struct page **pdata, int nr_pages, size_t offs, int count) { … } /** * p9_virtio_request - issue a request * @client: client instance issuing the request * @req: request to be issued * */ static int p9_virtio_request(struct p9_client *client, struct p9_req_t *req) { … } static int p9_get_mapped_pages(struct virtio_chan *chan, struct page ***pages, struct iov_iter *data, int count, size_t *offs, int *need_drop) { … } static void handle_rerror(struct p9_req_t *req, int in_hdr_len, size_t offs, struct page **pages) { … } /** * p9_virtio_zc_request - issue a zero copy request * @client: client instance issuing the request * @req: request to be issued * @uidata: user buffer that should be used for zero copy read * @uodata: user buffer that should be used for zero copy write * @inlen: read buffer size * @outlen: write buffer size * @in_hdr_len: reader header size, This is the size of response protocol data * */ static int p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, struct iov_iter *uidata, struct iov_iter *uodata, int inlen, int outlen, int in_hdr_len) { … } static ssize_t p9_mount_tag_show(struct device *dev, struct device_attribute *attr, char *buf) { … } static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); /** * p9_virtio_probe - probe for existence of 9P virtio channels * @vdev: virtio device to probe * * This probes for existing virtio channels. * */ static int p9_virtio_probe(struct virtio_device *vdev) { … } /** * p9_virtio_create - allocate a new virtio channel * @client: client instance invoking this transport * @devname: string identifying the channel to connect to (unused) * @args: args passed from sys_mount() for per-transport options (unused) * * This sets up a transport channel for 9p communication. Right now * we only match the first available channel, but eventually we could look up * alternate channels by matching devname versus a virtio_config entry. * We use a simple reference count mechanism to ensure that only a single * mount has a channel open at a time. * */ static int p9_virtio_create(struct p9_client *client, const char *devname, char *args) { … } /** * p9_virtio_remove - clean up resources associated with a virtio device * @vdev: virtio device to remove * */ static void p9_virtio_remove(struct virtio_device *vdev) { … } static struct virtio_device_id id_table[] = …; static unsigned int features[] = …; /* The standard "struct lguest_driver": */ static struct virtio_driver p9_virtio_drv = …; static struct p9_trans_module p9_virtio_trans = …; /* The standard init function */ static int __init p9_virtio_init(void) { … } static void __exit p9_virtio_cleanup(void) { … } module_init(…) …; module_exit(p9_virtio_cleanup); MODULE_ALIAS_9P(…) …; MODULE_DEVICE_TABLE(virtio, id_table); MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
Codebase Browser
linux