path: root/net/9p/client.c

/*
 * net/9p/clnt.c
 *
 * 9P Client
 *
 *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
 *
 *  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
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "protocol.h"

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

enum {
	Opt_msize,
	Opt_trans,
	Opt_legacy,
	Opt_err,
};

static const match_table_t tokens = {
	{Opt_msize, "msize=%u"},
	{Opt_legacy, "noextend"},
	{Opt_trans, "trans=%s"},
	{Opt_err, NULL},
};

static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);

/**
 * parse_options - parse mount options into client structure
 * @opts: options string passed from mount
 * @clnt: existing v9fs client information
 *
 * Return 0 upon success, -ERRNO upon failure
 */

static int parse_opts(char *opts, struct p9_client *clnt)
{
	char *options;
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	int ret = 0;

	clnt->dotu = 1;
	clnt->msize = 8192;

	if (!opts)
		return 0;

	options = kstrdup(opts, GFP_KERNEL);
	if (!options) {
		P9_DPRINTK(P9_DEBUG_ERROR,
				"failed to allocate copy of option string\n");
		return -ENOMEM;
	}

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		if (!*p)
			continue;
		token = match_token(p, tokens, args);
		if (token < Opt_trans) {
			int r = match_int(&args[0], &option);
			if (r < 0) {
				P9_DPRINTK(P9_DEBUG_ERROR,
					"integer field, but no integer?\n");
				ret = r;
				continue;
			}
		}
		switch (token) {
		case Opt_msize:
			clnt->msize = option;
			break;
		case Opt_trans:
			clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
			break;
		case Opt_legacy:
			clnt->dotu = 0;
			break;
		default:
			continue;
		}
	}

	kfree(options);
	return ret;
}

/**
 * p9_tag_alloc - lookup/allocate a request by tag
 * @c: client session to lookup tag within
 * @tag: numeric id for transaction
 *
 * this is a simple array lookup, but will grow the
 * request_slots as necessary to accomodate transaction
 * ids which did not previously have a slot.
 *
 * this code relies on the client spinlock to manage locks, its
 * possible we should switch to something else, but I'd rather
 * stick with something low-overhead for the common case.
 *
 */

static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
{
	unsigned long flags;
	int row, col;
	struct p9_req_t *req;

	/* This looks up the original request by tag so we know which
	 * buffer to read the data into */
	tag++;

	if (tag >= c->max_tag) {
		spin_lock_irqsave(&c->lock, flags);
		/* check again since original check was outside of lock */
		while (tag >= c->max_tag) {
			row = (tag / P9_ROW_MAXTAG);
			c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
					sizeof(struct p9_req_t), GFP_ATOMIC);

			if (!c->reqs[row]) {
				printk(KERN_ERR "Couldn't grow tag array\n");
				spin_unlock_irqrestore(&c->lock, flags);
				return ERR_PTR(-ENOMEM);
			}
			for (col = 0; col < P9_ROW_MAXTAG; col++) {
				c->reqs[row][col].status = REQ_STATUS_IDLE;
				c->reqs[row][col].tc = NULL;
			}
			c->max_tag += P9_ROW_MAXTAG;
		}
		spin_unlock_irqrestore(&c->lock, flags);
	}
	row = tag / P9_ROW_MAXTAG;
	col = tag % P9_ROW_MAXTAG;

	req = &c->reqs[row][col];
	if (!req->tc) {
		req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
		if (!req->wq) {
			printk(KERN_ERR "Couldn't grow tag array\n");
			return ERR_PTR(-ENOMEM);
		}
		init_waitqueue_head(req->wq);
		req->tc = kmalloc(sizeof(struct p9_fcall)+c->msize,
								GFP_KERNEL);
		req->rc = kmalloc(sizeof(struct p9_fcall)+c->msize,
								GFP_KERNEL);
		if ((!req->tc) || (!req->rc)) {
			printk(KERN_ERR "Couldn't grow tag array\n");
			kfree(req->tc);
			kfree(req->rc);
			kfree