linux/net/9p/mux.c

1059 lines
23 KiB
C

/*
* net/9p/mux.c
*
* Protocol Multiplexer
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2004-2005 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/kthread.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <net/9p/transport.h>
#include <net/9p/conn.h>
#define ERREQFLUSH 1
#define SCHED_TIMEOUT 10
#define MAXPOLLWADDR 2
enum {
Rworksched = 1, /* read work scheduled or running */
Rpending = 2, /* can read */
Wworksched = 4, /* write work scheduled or running */
Wpending = 8, /* can write */
};
enum {
None,
Flushing,
Flushed,
};
struct p9_mux_poll_task;
struct p9_req {
spinlock_t lock; /* protect request structure */
int tag;
struct p9_fcall *tcall;
struct p9_fcall *rcall;
int err;
p9_conn_req_callback cb;
void *cba;
int flush;
struct list_head req_list;
};
struct p9_conn {
spinlock_t lock; /* protect lock structure */
struct list_head mux_list;
struct p9_mux_poll_task *poll_task;
int msize;
unsigned char *extended;
struct p9_trans *trans;
struct p9_idpool *tagpool;
int err;
wait_queue_head_t equeue;
struct list_head req_list;
struct list_head unsent_req_list;
struct p9_fcall *rcall;
int rpos;
char *rbuf;
int wpos;
int wsize;
char *wbuf;
wait_queue_t poll_wait[MAXPOLLWADDR];
wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
poll_table pt;
struct work_struct rq;
struct work_struct wq;
unsigned long wsched;
};
struct p9_mux_poll_task {
struct task_struct *task;
struct list_head mux_list;
int muxnum;
};
struct p9_mux_rpc {
struct p9_conn *m;
int err;
struct p9_fcall *tcall;
struct p9_fcall *rcall;
wait_queue_head_t wqueue;
};
static int p9_poll_proc(void *);
static void p9_read_work(struct work_struct *work);
static void p9_write_work(struct work_struct *work);
static void p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
poll_table * p);
static u16 p9_mux_get_tag(struct p9_conn *);
static void p9_mux_put_tag(struct p9_conn *, u16);
static DEFINE_MUTEX(p9_mux_task_lock);
static struct workqueue_struct *p9_mux_wq;
static int p9_mux_num;
static int p9_mux_poll_task_num;
static struct p9_mux_poll_task p9_mux_poll_tasks[100];
int p9_mux_global_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
p9_mux_poll_tasks[i].task = NULL;
p9_mux_wq = create_workqueue("v9fs");
if (!p9_mux_wq) {
printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
return -ENOMEM;
}
return 0;
}
void p9_mux_global_exit(void)
{
destroy_workqueue(p9_mux_wq);
}
/**
* p9_mux_calc_poll_procs - calculates the number of polling procs
* based on the number of mounted v9fs filesystems.
*
* The current implementation returns sqrt of the number of mounts.
*/
static int p9_mux_calc_poll_procs(int muxnum)
{
int n;
if (p9_mux_poll_task_num)
n = muxnum / p9_mux_poll_task_num +
(muxnum % p9_mux_poll_task_num ? 1 : 0);
else
n = 1;
if (n > ARRAY_SIZE(p9_mux_poll_tasks))
n = ARRAY_SIZE(p9_mux_poll_tasks);
return n;
}
static int p9_mux_poll_start(struct p9_conn *m)
{
int i, n;
struct p9_mux_poll_task *vpt, *vptlast;
struct task_struct *pproc;
P9_DPRINTK(P9_DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, p9_mux_num,
p9_mux_poll_task_num);
mutex_lock(&p9_mux_task_lock);
n = p9_mux_calc_poll_procs(p9_mux_num + 1);
if (n > p9_mux_poll_task_num) {
for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
if (p9_mux_poll_tasks[i].task == NULL) {
vpt = &p9_mux_poll_tasks[i];
P9_DPRINTK(P9_DEBUG_MUX, "create proc %p\n",
vpt);
pproc = kthread_create(p9_poll_proc, vpt,
"v9fs-poll");
if (!IS_ERR(pproc)) {
vpt->task = pproc;
INIT_LIST_HEAD(&vpt->mux_list);
vpt->muxnum = 0;
p9_mux_poll_task_num++;
wake_up_process(vpt->task);
}
break;
}
}
if (i >= ARRAY_SIZE(p9_mux_poll_tasks))
P9_DPRINTK(P9_DEBUG_ERROR,
"warning: no free poll slots\n");
}
n = (p9_mux_num + 1) / p9_mux_poll_task_num +
((p9_mux_num + 1) % p9_mux_poll_task_num ? 1 : 0);
vptlast = NULL;
for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
vpt = &p9_mux_poll_tasks[i];
if (vpt->task != NULL) {
vptlast = vpt;
if (vpt->muxnum < n) {
P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
list_add(&m->mux_list, &vpt->mux_list);
vpt->muxnum++;
m->poll_task = vpt;
memset(&m->poll_waddr, 0,
sizeof(m->poll_waddr));
init_poll_funcptr(&m->pt, p9_pollwait);
break;
}
}
}
if (i >= ARRAY_SIZE(p9_mux_poll_tasks)) {
if (vptlast == NULL)
return -ENOMEM;
P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
list_add(&m->mux_list, &vptlast->mux_list);
vptlast->muxnum++;
m->poll_task = vptlast;
memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
init_poll_funcptr(&m->pt, p9_pollwait);
}
p9_mux_num++;
mutex_unlock(&p9_mux_task_lock);
return 0;
}
static void p9_mux_poll_stop(struct p9_conn *m)
{
int i;
struct p9_mux_poll_task *vpt;
mutex_lock(&p9_mux_task_lock);
vpt = m->poll_task;
list_del(&m->mux_list);
for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
if (m->poll_waddr[i] != NULL) {
remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
m->poll_waddr[i] = NULL;
}
}
vpt->muxnum--;
if (!vpt->muxnum) {
P9_DPRINTK(P9_DEBUG_MUX, "destroy proc %p\n", vpt);
kthread_stop(vpt->task);
vpt->task = NULL;
p9_mux_poll_task_num--;
}
p9_mux_num--;
mutex_unlock(&p9_mux_task_lock);
}
/**
* p9_conn_create - allocate and initialize the per-session mux data
* Creates the polling task if this is the first session.
*
* @trans - transport structure
* @msize - maximum message size
* @extended - pointer to the extended flag
*/
struct p9_conn *p9_conn_create(struct p9_trans *trans, int msize,
unsigned char *extended)
{
int i, n;
struct p9_conn *m, *mtmp;
P9_DPRINTK(P9_DEBUG_MUX, "transport %p msize %d\n", trans, msize);
m = kmalloc(sizeof(struct p9_conn), GFP_KERNEL);
if (!m)
return ERR_PTR(-ENOMEM);
spin_lock_init(&m->lock);
INIT_LIST_HEAD(&m->mux_list);
m->msize = msize;
m->extended = extended;
m->trans = trans;
m->tagpool = p9_idpool_create();
if (IS_ERR(m->tagpool)) {
mtmp = ERR_PTR(-ENOMEM);
kfree(m);
return mtmp;
}
m->err = 0;
init_waitqueue_head(&m->equeue);
INIT_LIST_HEAD(&m->req_list);
INIT_LIST_HEAD(&m->unsent_req_list);
m->rcall = NULL;
m->rpos = 0;
m->rbuf = NULL;
m->wpos = m->wsize = 0;
m->wbuf = NULL;
INIT_WORK(&m->rq, p9_read_work);
INIT_WORK(&m->wq, p9_write_work);
m->wsched = 0;
memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
m->poll_task = NULL;
n = p9_mux_poll_start(m);
if (n) {
kfree(m);
return ERR_PTR(n);
}
n = trans->poll(trans, &m->pt);
if (n & POLLIN) {
P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
set_bit(Rpending, &m->wsched);
}
if (n & POLLOUT) {
P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
set_bit(Wpending, &m->wsched);
}
for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
if (IS_ERR(m->poll_waddr[i])) {
p9_mux_poll_stop(m);
mtmp = (void *)m->poll_waddr; /* the error code */
kfree(m);
m = mtmp;
break;
}
}
return m;
}
EXPORT_SYMBOL(p9_conn_create);
/**
* p9_mux_destroy - cancels all pending requests and frees mux resources
*/
void p9_conn_destroy(struct p9_conn *m)
{
P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
m->mux_list.prev, m->mux_list.next);
p9_conn_cancel(m, -ECONNRESET);
if (!list_empty(&m->req_list)) {
/* wait until all processes waiting on this session exit */
P9_DPRINTK(P9_DEBUG_MUX,
"mux %p waiting for empty request queue\n", m);
wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
P9_DPRINTK(P9_DEBUG_MUX, "mux %p request queue empty: %d\n", m,
list_empty(&m->req_list));
}
p9_mux_poll_stop(m);
m->trans = NULL;
p9_idpool_destroy(m->tagpool);
kfree(m);
}
EXPORT_SYMBOL(p9_conn_destroy);
/**
* p9_pollwait - 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)
{
int i;
struct p9_conn *m;
m = container_of(p, struct p9_conn, pt);
for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
if (m->poll_waddr[i] == NULL)
break;
if (i >= ARRAY_SIZE(m->poll_waddr)) {
P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
return;
}
m->poll_waddr[i] = wait_address;
if (!wait_address) {
P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
m->poll_waddr[i] = ERR_PTR(-EIO);
return;
}
init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
add_wait_queue(wait_address, &m->poll_wait[i]);
}
/**
* p9_poll_mux - polls a mux and schedules read or write works if necessary
*/
static void p9_poll_mux(struct p9_conn *m)
{
int n;
if (m->err < 0)
return;
n = m->trans->poll(m->trans, NULL);
if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
P9_DPRINTK(P9_DEBUG_MUX, "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_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
if (!test_and_set_bit(Rworksched, &m->wsched)) {
P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
queue_work(p9_mux_wq, &m->rq);
}
}
if (n & POLLOUT) {
set_bit(Wpending, &m->wsched);
P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
if ((m->wsize || !list_empty(&m->unsent_req_list))
&& !test_and_set_bit(Wworksched, &m->wsched)) {
P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
queue_work(p9_mux_wq, &m->wq);
}
}
}
/**
* p9_poll_proc - polls all v9fs transports for new events and queues
* the appropriate work to the work queue
*/
static int p9_poll_proc(void *a)
{
struct p9_conn *m, *mtmp;
struct p9_mux_poll_task *vpt;
vpt = a;
P9_DPRINTK(P9_DEBUG_MUX, "start %p %p\n", current, vpt);
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
p9_poll_mux(m);
}
P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
schedule_timeout(SCHED_TIMEOUT * HZ);
}
__set_current_state(TASK_RUNNING);
P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
return 0;
}
/**
* p9_write_work - called when a transport can send some data
*/
static void p9_write_work(struct work_struct *work)
{
int n, err;
struct p9_conn *m;
struct p9_req *req;
m = container_of(work, struct p9_conn, wq);
if (m->err < 0) {
clear_bit(Wworksched, &m->wsched);
return;
}
if (!m->wsize) {
if (list_empty(&m->unsent_req_list)) {
clear_bit(Wworksched, &m->wsched);
return;
}
spin_lock(&m->lock);
again:
req = list_entry(m->unsent_req_list.next, struct p9_req,
req_list);
list_move_tail(&req->req_list, &m->req_list);
if (req->err == ERREQFLUSH)
goto again;
m->wbuf = req->tcall->sdata;
m->wsize = req->tcall->size;
m->wpos = 0;
spin_unlock(&m->lock);
}
P9_DPRINTK(P9_DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos,
m->wsize);
clear_bit(Wpending, &m->wsched);
err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
P9_DPRINTK(P9_DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
if (err == -EAGAIN) {
clear_bit(Wworksched, &m->wsched);
return;
}
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;
if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
if (test_and_clear_bit(Wpending, &m->wsched))
n = POLLOUT;
else
n = m->trans->poll(m->trans, NULL);
if (n & POLLOUT) {
P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
queue_work(p9_mux_wq, &m->wq);
} else
clear_bit(Wworksched, &m->wsched);
} else
clear_bit(Wworksched, &m->wsched);
return;
error:
p9_conn_cancel(m, err);
clear_bit(Wworksched, &m->wsched);
}
static void process_request(struct p9_conn *m, struct p9_req *req)
{
int ecode;
struct p9_str *ename;
if (!req->err && req->rcall->id == P9_RERROR) {
ecode = req->rcall->params.rerror.errno;
ename = &req->rcall->params.rerror.error;
P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
ename->str);
if (*m->extended)
req->err = -ecode;
if (!req->err) {
req->err = p9_errstr2errno(ename->str, ename->len);
if (!req->err) { /* string match failed */
PRINT_FCALL_ERROR("unknown error", req->rcall);
}
if (!req->err)
req->err = -ESERVERFAULT;
}
} else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
P9_DPRINTK(P9_DEBUG_ERROR,
"fcall mismatch: expected %d, got %d\n",
req->tcall->id + 1, req->rcall->id);
if (!req->err)
req->err = -EIO;
}
}
/**
* p9_read_work - called when there is some data to be read from a transport
*/
static void p9_read_work(struct work_struct *work)
{
int n, err;
struct p9_conn *m;
struct p9_req *req, *rptr, *rreq;
struct p9_fcall *rcall;
char *rbuf;
m = container_of(work, struct p9_conn, rq);
if (m->err < 0)
return;
rcall = NULL;
P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
if (!m->rcall) {
m->rcall =
kmalloc(sizeof(struct p9_fcall) + m->msize, GFP_KERNEL);
if (!m->rcall) {
err = -ENOMEM;
goto error;
}
m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
m->rpos = 0;
}
clear_bit(Rpending, &m->wsched);
err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
if (err == -EAGAIN) {
clear_bit(Rworksched, &m->wsched);
return;
}
if (err <= 0)
goto error;
m->rpos += err;
while (m->rpos > 4) {
n = le32_to_cpu(*(__le32 *) m->rbuf);
if (n >= m->msize) {
P9_DPRINTK(P9_DEBUG_ERROR,
"requested packet size too big: %d\n", n);
err = -EIO;
goto error;
}
if (m->rpos < n)
break;
err =
p9_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
if (err < 0) {
goto error;
}
#ifdef CONFIG_NET_9P_DEBUG
if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
char buf[150];
p9_printfcall(buf, sizeof(buf), m->rcall,
*m->extended);
printk(KERN_NOTICE ">>> %p %s\n", m, buf);
}
#endif
rcall = m->rcall;
rbuf = m->rbuf;
if (m->rpos > n) {
m->rcall = kmalloc(sizeof(struct p9_fcall) + m->msize,
GFP_KERNEL);
if (!m->rcall) {
err = -ENOMEM;
goto error;
}
m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
memmove(m->rbuf, rbuf + n, m->rpos - n);
m->rpos -= n;
} else {
m->rcall = NULL;
m->rbuf = NULL;
m->rpos = 0;
}
P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
rcall->id, rcall->tag);
req = NULL;
spin_lock(&m->lock);
list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
if (rreq->tag == rcall->tag) {
req = rreq;
if (req->flush != Flushing)
list_del(&req->req_list);
break;
}
}
spin_unlock(&m->lock);
if (req) {
req->rcall = rcall;
process_request(m, req);
if (req->flush != Flushing) {
if (req->cb)
(*req->cb) (req, req->cba);
else
kfree(req->rcall);
wake_up(&m->equeue);
}
} else {
if (err >= 0 && rcall->id != P9_RFLUSH)
P9_DPRINTK(P9_DEBUG_ERROR,
"unexpected response mux %p id %d tag %d\n",
m, rcall->id, rcall->tag);
kfree(rcall);
}
}
if (!list_empty(&m->req_list)) {
if (test_and_clear_bit(Rpending, &m->wsched))
n = POLLIN;
else
n = m->trans->poll(m->trans, NULL);
if (n & POLLIN) {
P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
queue_work(p9_mux_wq, &m->rq);
} else
clear_bit(Rworksched, &m->wsched);
} else
clear_bit(Rworksched, &m->wsched);
return;
error:
p9_conn_cancel(m, err);
clear_bit(Rworksched, &m->wsched);
}
/**
* p9_send_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. Can return errors
* that can be retrieved by PTR_ERR macros.
*
* @m: mux data
* @tc: request to be sent
* @cb: callback function to call when response is received
* @cba: parameter to pass to the callback function
*/
static struct p9_req *p9_send_request(struct p9_conn *m,
struct p9_fcall *tc,
p9_conn_req_callback cb, void *cba)
{
int n;
struct p9_req *req;
P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
tc, tc->id);
if (m->err < 0)
return ERR_PTR(m->err);
req = kmalloc(sizeof(struct p9_req), GFP_KERNEL);
if (!req)
return ERR_PTR(-ENOMEM);
if (tc->id == P9_TVERSION)
n = P9_NOTAG;
else
n = p9_mux_get_tag(m);
if (n < 0)
return ERR_PTR(-ENOMEM);
p9_set_tag(tc, n);
#ifdef CONFIG_NET_9P_DEBUG
if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
char buf[150];
p9_printfcall(buf, sizeof(buf), tc, *m->extended);
printk(KERN_NOTICE "<<< %p %s\n", m, buf);
}
#endif
spin_lock_init(&req->lock);
req->tag = n;
req->tcall = tc;
req->rcall = NULL;
req->err = 0;
req->cb = cb;
req->cba = cba;
req->flush = None;
spin_lock(&m->lock);
list_add_tail(&req->req_list, &m->unsent_req_list);
spin_unlock(&m->lock);
if (test_and_clear_bit(Wpending, &m->wsched))
n = POLLOUT;
else
n = m->trans->poll(m->trans, NULL);
if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
queue_work(p9_mux_wq, &m->wq);
return req;
}
static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
{
p9_mux_put_tag(m, req->tag);
kfree(req);
}
static void p9_mux_flush_cb(struct p9_req *freq, void *a)
{
p9_conn_req_callback cb;
int tag;
struct p9_conn *m;
struct p9_req *req, *rreq, *rptr;
m = a;
P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
freq->tcall, freq->rcall, freq->err,
freq->tcall->params.tflush.oldtag);
spin_lock(&m->lock);
cb = NULL;
tag = freq->tcall->params.tflush.oldtag;
req = NULL;
list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
if (rreq->tag == tag) {
req = rreq;
list_del(&req->req_list);
break;
}
}
spin_unlock(&m->lock);
if (req) {
spin_lock(&req->lock);
req->flush = Flushed;
spin_unlock(&req->lock);
if (req->cb)
(*req->cb) (req, req->cba);
else
kfree(req->rcall);
wake_up(&m->equeue);
}
kfree(freq->tcall);
kfree(freq->rcall);
p9_mux_free_request(m, freq);
}
static int
p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
{
struct p9_fcall *fc;
struct p9_req *rreq, *rptr;
P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
/* if a response was received for a request, do nothing */
spin_lock(&req->lock);
if (req->rcall || req->err) {
spin_unlock(&req->lock);
P9_DPRINTK(P9_DEBUG_MUX,
"mux %p req %p response already received\n", m, req);
return 0;
}
req->flush = Flushing;
spin_unlock(&req->lock);
spin_lock(&m->lock);
/* if the request is not sent yet, just remove it from the list */
list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
if (rreq->tag == req->tag) {
P9_DPRINTK(P9_DEBUG_MUX,
"mux %p req %p request is not sent yet\n", m, req);
list_del(&rreq->req_list);
req->flush = Flushed;
spin_unlock(&m->lock);
if (req->cb)
(*req->cb) (req, req->cba);
return 0;
}
}
spin_unlock(&m->lock);
clear_thread_flag(TIF_SIGPENDING);
fc = p9_create_tflush(req->tag);
p9_send_request(m, fc, p9_mux_flush_cb, m);
return 1;
}
static void
p9_conn_rpc_cb(struct p9_req *req, void *a)
{
struct p9_mux_rpc *r;
P9_DPRINTK(P9_DEBUG_MUX, "req %p r %p\n", req, a);
r = a;
r->rcall = req->rcall;
r->err = req->err;
if (req->flush != None && !req->err)
r->err = -ERESTARTSYS;
wake_up(&r->wqueue);
}
/**
* p9_mux_rpc - sends 9P request and waits until a response is available.
* The function can be interrupted.
* @m: mux data
* @tc: request to be sent
* @rc: pointer where a pointer to the response is stored
*/
int
p9_conn_rpc(struct p9_conn *m, struct p9_fcall *tc,
struct p9_fcall **rc)
{
int err, sigpending;
unsigned long flags;
struct p9_req *req;
struct p9_mux_rpc r;
r.err = 0;
r.tcall = tc;
r.rcall = NULL;
r.m = m;
init_waitqueue_head(&r.wqueue);
if (rc)
*rc = NULL;
sigpending = 0;
if (signal_pending(current)) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
}
req = p9_send_request(m, tc, p9_conn_rpc_cb, &r);
if (IS_ERR(req)) {
err = PTR_ERR(req);
P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
return err;
}
err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
if (r.err < 0)
err = r.err;
if (err == -ERESTARTSYS && m->trans->status == Connected
&& m->err == 0) {
if (p9_mux_flush_request(m, req)) {
/* wait until we get response of the flush message */
do {
clear_thread_flag(TIF_SIGPENDING);
err = wait_event_interruptible(r.wqueue,
r.rcall || r.err);
} while (!r.rcall && !r.err && err == -ERESTARTSYS &&
m->trans->status == Connected && !m->err);
err = -ERESTARTSYS;
}
sigpending = 1;
}
if (sigpending) {
spin_lock_irqsave(&current->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(&current->sighand->siglock, flags);
}
if (rc)
*rc = r.rcall;
else
kfree(r.rcall);
p9_mux_free_request(m, req);
if (err > 0)
err = -EIO;
return err;
}
EXPORT_SYMBOL(p9_conn_rpc);
#ifdef P9_NONBLOCK
/**
* p9_conn_rpcnb - sends 9P request without waiting for response.
* @m: mux data
* @tc: request to be sent
* @cb: callback function to be called when response arrives
* @cba: value to pass to the callback function
*/
int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
p9_conn_req_callback cb, void *a)
{
int err;
struct p9_req *req;
req = p9_send_request(m, tc, cb, a);
if (IS_ERR(req)) {
err = PTR_ERR(req);
P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
return PTR_ERR(req);
}
P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
return 0;
}
EXPORT_SYMBOL(p9_conn_rpcnb);
#endif /* P9_NONBLOCK */
/**
* p9_conn_cancel - cancel all pending requests with error
* @m: mux data
* @err: error code
*/
void p9_conn_cancel(struct p9_conn *m, int err)
{
struct p9_req *req, *rtmp;
LIST_HEAD(cancel_list);
P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
m->err = err;
spin_lock(&m->lock);
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(&m->lock);
list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
list_del(&req->req_list);
if (!req->err)
req->err = err;
if (req->cb)
(*req->cb) (req, req->cba);
else
kfree(req->rcall);
}
wake_up(&m->equeue);
}
EXPORT_SYMBOL(p9_conn_cancel);
static u16 p9_mux_get_tag(struct p9_conn *m)
{
int tag;
tag = p9_idpool_get(m->tagpool);
if (tag < 0)
return P9_NOTAG;
else
return (u16) tag;
}
static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
{
if (tag != P9_NOTAG && p9_idpool_check(tag, m->tagpool))
p9_idpool_put(tag, m->tagpool);
}