/* * 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) { mutex_unlock(&p9_mux_task_lock); 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(¤t->sighand->siglock, flags); recalc_sigpending(); spin_unlock_irqrestore(¤t->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); }