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-rw-r--r--net/9p/mux.c1050
1 files changed, 1050 insertions, 0 deletions
diff --git a/net/9p/mux.c b/net/9p/mux.c
new file mode 100644
index 000000000000..c3aa87bc8b97
--- /dev/null
+++ b/net/9p/mux.c
@@ -0,0 +1,1050 @@
+/*
+ * 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 <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_transport *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_transport *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 (!m->tagpool) {
+ kfree(m);
+ return ERR_PTR(PTR_ERR(m->tagpool));
+ }
+
+ 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)
+ 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;
+
+ 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);
+}
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-18 19:23:12 +0000