cregit-Linux how code gets into the kernel

Release 4.8 net/9p/trans_fd.c

Directory: net/9p
/*
 * linux/fs/9p/trans_fd.c
 *
 * Fd transport layer.  Includes deprecated socket layer.
 *
 *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
 *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
 *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/in.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/ipv6.h>
#include <linux/kthread.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/un.h>
#include <linux/uaccess.h>
#include <linux/inet.h>
#include <linux/idr.h>
#include <linux/file.h>
#include <linux/parser.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>

#include <linux/syscalls.h> /* killme */


#define P9_PORT 564

#define MAX_SOCK_BUF (64*1024)

#define MAXPOLLWADDR	2

/**
 * struct p9_fd_opts - per-transport options
 * @rfd: file descriptor for reading (trans=fd)
 * @wfd: file descriptor for writing (trans=fd)
 * @port: port to connect to (trans=tcp)
 *
 */


struct p9_fd_opts {
	
int rfd;
	
int wfd;
	
u16 port;
	
int privport;
};

/*
  * Option Parsing (code inspired by NFS code)
  *  - a little lazy - parse all fd-transport options
  */

enum {
	/* Options that take integer arguments */
	



Opt_port, Opt_rfdno, Opt_wfdno, Opt_err,
	/* Options that take no arguments */
	
Opt_privport,
};


static const match_table_t tokens = {
	{Opt_port, "port=%u"},
	{Opt_rfdno, "rfdno=%u"},
	{Opt_wfdno, "wfdno=%u"},
	{Opt_privport, "privport"},
	{Opt_err, NULL},
};

enum {
	
Rworksched = 1,		/* read work scheduled or running */
	
Rpending = 2,		/* can read */
	
Wworksched = 4,		/* write work scheduled or running */
	
Wpending = 8,		/* can write */
};


struct p9_poll_wait {
	
struct p9_conn *conn;
	
wait_queue_t wait;
	
wait_queue_head_t *wait_addr;
};

/**
 * struct p9_conn - fd mux connection state information
 * @mux_list: list link for mux to manage multiple connections (?)
 * @client: reference to client instance for this connection
 * @err: error state
 * @req_list: accounting for requests which have been sent
 * @unsent_req_list: accounting for requests that haven't been sent
 * @req: current request being processed (if any)
 * @tmp_buf: temporary buffer to read in header
 * @rc: temporary fcall for reading current frame
 * @wpos: write position for current frame
 * @wsize: amount of data to write for current frame
 * @wbuf: current write buffer
 * @poll_pending_link: pending links to be polled per conn
 * @poll_wait: array of wait_q's for various worker threads
 * @pt: poll state
 * @rq: current read work
 * @wq: current write work
 * @wsched: ????
 *
 */


struct p9_conn {
	
struct list_head mux_list;
	
struct p9_client *client;
	
int err;
	
struct list_head req_list;
	
struct list_head unsent_req_list;
	
struct p9_req_t *req;
	
char tmp_buf[7];
	
struct p9_fcall rc;
	
int wpos;
	
int wsize;
	
char *wbuf;
	
struct list_head poll_pending_link;
	
struct p9_poll_wait poll_wait[MAXPOLLWADDR];
	
poll_table pt;
	
struct work_struct rq;
	
struct work_struct wq;
	
unsigned long wsched;
};

/**
 * struct p9_trans_fd - transport state
 * @rd: reference to file to read from
 * @wr: reference of file to write to
 * @conn: connection state reference
 *
 */


struct p9_trans_fd {
	
struct file *rd;
	
struct file *wr;
	
struct p9_conn conn;
};

static void p9_poll_workfn(struct work_struct *work);

static DEFINE_SPINLOCK(p9_poll_lock);
static LIST_HEAD(p9_poll_pending_list);
static DECLARE_WORK(p9_poll_work, p9_poll_workfn);


static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT;

static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT;


static void p9_mux_poll_stop(struct p9_conn *m) { unsigned long flags; int i; for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { struct p9_poll_wait *pwait = &m->poll_wait[i]; if (pwait->wait_addr) { remove_wait_queue(pwait->wait_addr, &pwait->wait); pwait->wait_addr = NULL; } } spin_lock_irqsave(&p9_poll_lock, flags); list_del_init(&m->poll_pending_link); spin_unlock_irqrestore(&p9_poll_lock, flags); }

Contributors

PersonTokensPropCommitsCommitProp
tejun heotejun heo8382.18%150.00%
eric van hensbergeneric van hensbergen1817.82%150.00%
Total101100.00%2100.00%

/** * p9_conn_cancel - cancel all pending requests with error * @m: mux data * @err: error code * */
static void p9_conn_cancel(struct p9_conn *m, int err) { struct p9_req_t *req, *rtmp; unsigned long flags; LIST_HEAD(cancel_list); p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err); spin_lock_irqsave(&m->client->lock, flags); if (m->err) { spin_unlock_irqrestore(&m->client->lock, flags); return; } m->err = err; list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) { list_move(&req->req_list, &cancel_list); } list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { list_move(&req->req_list, &cancel_list); } spin_unlock_irqrestore(&m->client->lock, flags); list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); list_del(&req->req_list); if (!req->t_err) req->t_err = err; p9_client_cb(m->client, req, REQ_STATUS_ERROR); } }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen16786.98%562.50%
dominique martinetdominique martinet157.81%112.50%
latchesar ionkovlatchesar ionkov84.17%112.50%
joe perchesjoe perches21.04%112.50%
Total192100.00%8100.00%


static int p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt) { int ret, n; struct p9_trans_fd *ts = NULL; if (client && client->status == Connected) ts = client->trans; if (!ts) return -EREMOTEIO; if (!ts->rd->f_op->poll) return -EIO; if (!ts->wr->f_op->poll) return -EIO; ret = ts->rd->f_op->poll(ts->rd, pt); if (ret < 0) return ret; if (ts->rd != ts->wr) { n = ts->wr->f_op->poll(ts->wr, pt); if (n < 0) return n; ret = (ret & ~POLLOUT) | (n & ~POLLIN); } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen15090.36%480.00%
tejun heotejun heo169.64%120.00%
Total166100.00%5100.00%

/** * p9_fd_read- read from a fd * @client: client instance * @v: buffer to receive data into * @len: size of receive buffer * */
static int p9_fd_read(struct p9_client *client, void *v, int len) { int ret; struct p9_trans_fd *ts = NULL; if (client && client->status != Disconnected) ts = client->trans; if (!ts) return -EREMOTEIO; if (!(ts->rd->f_flags & O_NONBLOCK)) p9_debug(P9_DEBUG_ERROR, "blocking read ...\n"); ret = kernel_read(ts->rd, ts->rd->f_pos, v, len); if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) client->status = Disconnected; return ret; }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen10589.74%250.00%
tejun heotejun heo119.40%125.00%
joe perchesjoe perches10.85%125.00%
Total117100.00%4100.00%

/** * p9_read_work - called when there is some data to be read from a transport * @work: container of work to be done * */
static void p9_read_work(struct work_struct *work) { int n, err; struct p9_conn *m; int status = REQ_STATUS_ERROR; m = container_of(work, struct p9_conn, rq); if (m->err < 0) return; p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset); if (!m->rc.sdata) { m->rc.sdata = m->tmp_buf; m->rc.offset = 0; m->rc.capacity = 7; /* start by reading header */ } clear_bit(Rpending, &m->wsched); p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n", m, m->rc.offset, m->rc.capacity, m->rc.capacity - m->rc.offset); err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset, m->rc.capacity - m->rc.offset); p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err); if (err == -EAGAIN) goto end_clear; if (err <= 0) goto error; m->rc.offset += err; /* header read in */ if ((!m->req) && (m->rc.offset == m->rc.capacity)) { p9_debug(P9_DEBUG_TRANS, "got new header\n"); err = p9_parse_header(&m->rc, NULL, NULL, NULL, 0); if (err) { p9_debug(P9_DEBUG_ERROR, "error parsing header: %d\n", err); goto error; } if (m->rc.size >= m->client->msize) { p9_debug(P9_DEBUG_ERROR, "requested packet size too big: %d\n", m->rc.size); err = -EIO; goto error; } p9_debug(P9_DEBUG_TRANS, "mux %p pkt: size: %d bytes tag: %d\n", m, m->rc.size, m->rc.tag); m->req = p9_tag_lookup(m->client, m->rc.tag); if (!m->req || (m->req->status != REQ_STATUS_SENT)) { p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", m->rc.tag); err = -EIO; goto error; } if (m->req->rc == NULL) { p9_debug(P9_DEBUG_ERROR, "No recv fcall for tag %d (req %p), disconnecting!\n", m->rc.tag, m->req); m->req = NULL; err = -EIO; goto error; } m->rc.sdata = (char *)m->req->rc + sizeof(struct p9_fcall); memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity); m->rc.capacity = m->rc.size; } /* packet is read in * not an else because some packets (like clunk) have no payload */ if ((m->req) && (m->rc.offset == m->rc.capacity)) { p9_debug(P9_DEBUG_TRANS, "got new packet\n"); spin_lock(&m->client->lock); if (m->req->status != REQ_STATUS_ERROR) status = REQ_STATUS_RCVD; list_del(&m->req->req_list); spin_unlock(&m->client->lock); p9_client_cb(m->client, m->req, status); m->rc.sdata = NULL; m->rc.offset = 0; m->rc.capacity = 0; m->req = NULL; } end_clear: clear_bit(Rworksched, &m->wsched); if (!list_empty(&m->req_list)) { if (test_and_clear_bit(Rpending, &m->wsched)) n = POLLIN; else n = p9_fd_poll(m->client, NULL); if ((n & POLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) { p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); schedule_work(&m->rq); } } return; error: p9_conn_cancel(m, err); clear_bit(Rworksched, &m->wsched); }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen48767.27%746.67%
dominique martinetdominique martinet15921.96%320.00%
simon derrsimon derr283.87%16.67%
latchesar ionkovlatchesar ionkov243.31%16.67%
tejun heotejun heo172.35%213.33%
joe perchesjoe perches91.24%16.67%
Total724100.00%15100.00%

/** * p9_fd_write - write to a socket * @client: client instance * @v: buffer to send data from * @len: size of send buffer * */
static int p9_fd_write(struct p9_client *client, void *v, int len) { int ret; mm_segment_t oldfs; struct p9_trans_fd *ts = NULL; if (client && client->status != Disconnected) ts = client->trans; if (!ts) return -EREMOTEIO; if (!(ts->wr->f_flags & O_NONBLOCK)) p9_debug(P9_DEBUG_ERROR, "blocking write ...\n"); oldfs = get_fs(); set_fs(get_ds()); /* The cast to a user pointer is valid due to the set_fs() */ ret = vfs_write(ts->wr, (__force void __user *)v, len, &ts->wr->f_pos); set_fs(oldfs); if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) client->status = Disconnected; return ret; }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen14298.61%360.00%
joe perchesjoe perches10.69%120.00%
hannes ederhannes eder10.69%120.00%
Total144100.00%5100.00%

/** * p9_write_work - called when a transport can send some data * @work: container for work to be done * */
static void p9_write_work(struct work_struct *work) { int n, err; struct p9_conn *m; struct p9_req_t *req; m = container_of(work, struct p9_conn, wq); if (m->err < 0) { clear_bit(Wworksched, &m->wsched); return; } if (!m->wsize) { spin_lock(&m->client->lock); if (list_empty(&m->unsent_req_list)) { clear_bit(Wworksched, &m->wsched); spin_unlock(&m->client->lock); return; } req = list_entry(m->unsent_req_list.next, struct p9_req_t, req_list); req->status = REQ_STATUS_SENT; p9_debug(P9_DEBUG_TRANS, "move req %p\n", req); list_move_tail(&req->req_list, &m->req_list); m->wbuf = req->tc->sdata; m->wsize = req->tc->size; m->wpos = 0; spin_unlock(&m->client->lock); } p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n", m, m->wpos, m->wsize); clear_bit(Wpending, &m->wsched); err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos); p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err); if (err == -EAGAIN) goto end_clear; if (err < 0) goto error; else if (err == 0) { err = -EREMOTEIO; goto error; } m->wpos += err; if (m->wpos == m->wsize) m->wpos = m->wsize = 0; end_clear: clear_bit(Wworksched, &m->wsched); if (m->wsize || !list_empty(&m->unsent_req_list)) { if (test_and_clear_bit(Wpending, &m->wsched)) n = POLLOUT; else n = p9_fd_poll(m->client, NULL); if ((n & POLLOUT) && !test_and_set_bit(Wworksched, &m->wsched)) { p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); schedule_work(&m->wq); } } return; error: p9_conn_cancel(m, err); clear_bit(Wworksched, &m->wsched); }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen37687.24%545.45%
simon derrsimon derr429.74%327.27%
latchesar ionkovlatchesar ionkov81.86%19.09%
joe perchesjoe perches40.93%19.09%
tejun heotejun heo10.23%19.09%
Total431100.00%11100.00%


static int p9_pollwake(wait_queue_t *wait, unsigned int mode, int sync, void *key) { struct p9_poll_wait *pwait = container_of(wait, struct p9_poll_wait, wait); struct p9_conn *m = pwait->conn; unsigned long flags; spin_lock_irqsave(&p9_poll_lock, flags); if (list_empty(&m->poll_pending_link)) list_add_tail(&m->poll_pending_link, &p9_poll_pending_list); spin_unlock_irqrestore(&p9_poll_lock, flags); schedule_work(&p9_poll_work); return 1; }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen8993.68%250.00%
tejun heotejun heo55.26%125.00%
eric dumazeteric dumazet11.05%125.00%
Total95100.00%4100.00%

/** * p9_pollwait - add poll task to the wait queue * @filp: file pointer being polled * @wait_address: wait_q to block on * @p: poll state * * called by files poll operation to add v9fs-poll task to files wait queue */
static void p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p) { struct p9_conn *m = container_of(p, struct p9_conn, pt); struct p9_poll_wait *pwait = NULL; int i; for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { if (m->poll_wait[i].wait_addr == NULL) { pwait = &m->poll_wait[i]; break; } } if (!pwait) { p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n"); return; } pwait->conn = m; pwait->wait_addr = wait_address; init_waitqueue_func_entry(&pwait->wait, p9_pollwake); add_wait_queue(wait_address, &pwait->wait); }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen13699.27%266.67%
joe perchesjoe perches10.73%133.33%
Total137100.00%3100.00%

/** * p9_conn_create - initialize the per-session mux data * @client: client instance * * Note: Creates the polling task if this is the first session. */
static void p9_conn_create(struct p9_client *client) { int n; struct p9_trans_fd *ts = client->trans; struct p9_conn *m = &ts->conn; p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize); INIT_LIST_HEAD(&m->mux_list); m->client = client; INIT_LIST_HEAD(&m->req_list); INIT_LIST_HEAD(&m->unsent_req_list); INIT_WORK(&m->rq, p9_read_work); INIT_WORK(&m->wq, p9_write_work); INIT_LIST_HEAD(&m->poll_pending_link); init_poll_funcptr(&m->pt, p9_pollwait); n = p9_fd_poll(client, &m->pt); if (n & POLLIN) { p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); set_bit(Rpending, &m->wsched); } if (n & POLLOUT) { p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); set_bit(Wpending, &m->wsched); } }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen16290.00%360.00%
simon derrsimon derr158.33%120.00%
joe perchesjoe perches31.67%120.00%
Total180100.00%5100.00%

/** * p9_poll_mux - polls a mux and schedules read or write works if necessary * @m: connection to poll * */
static void p9_poll_mux(struct p9_conn *m) { int n; if (m->err < 0) return; n = p9_fd_poll(m->client, NULL); if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) { p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n); if (n >= 0) n = -ECONNRESET; p9_conn_cancel(m, n); } if (n & POLLIN) { set_bit(Rpending, &m->wsched); p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); if (!test_and_set_bit(Rworksched, &m->wsched)) { p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); schedule_work(&m->rq); } } if (n & POLLOUT) { set_bit(Wpending, &m->wsched); p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); if ((m->wsize || !list_empty(&m->unsent_req_list)) && !test_and_set_bit(Wworksched, &m->wsched)) { p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); schedule_work(&m->wq); } } }

Contributors

PersonTokensPropCommitsCommitProp
eric van hensbergeneric van hensbergen20796.73%360.00%
joe perchesjoe perches52.34%120.00%
tejun heotejun heo20.93%120.00%
Total214100.00%5100.00%

/** * p9_fd_request - send 9P request * The function can sleep until the request is scheduled for sending. * The function can be interrupted. Return from the function is not * a guarantee that the request is sent successfully. * * @client: client instance * @req: request to be sent * */
static int p9_fd_request(struct p9_client *client, struct p9_req_t *req) { int n; struct p9_trans_fd *ts = client->trans; struct p9_conn *m = &ts->conn; p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n", m, current, req->tc, req->tc->id); if (m->err < 0) return m->err; spin_lock(&client->lock); req->status = REQ_STATUS_UNSENT; list_add_tail(&req->req_list, &m->unsent_req_list); spin_unlock(&client->lock); if (test_and_clear_bit(Wpending, &m->