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-rw-r--r--fs/9p/mux.c440
1 files changed, 440 insertions, 0 deletions
diff --git a/fs/9p/mux.c b/fs/9p/mux.c
new file mode 100644
index 000000000000..8ebc1af2c245
--- /dev/null
+++ b/fs/9p/mux.c
@@ -0,0 +1,440 @@
+/*
+ * linux/fs/9p/mux.c
+ *
+ * Protocol Multiplexer
+ *
+ * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ * Copyright (C) 2004 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 as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/kthread.h>
+#include <linux/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "transport.h"
+#include "conv.h"
+#include "mux.h"
+
+/**
+ * dprintcond - print condition of session info
+ * @v9ses: session info structure
+ * @req: RPC request structure
+ *
+ */
+
+static inline int
+dprintcond(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
+{
+ dprintk(DEBUG_MUX, "condition: %d, %p\n", v9ses->transport->status,
+ req->rcall);
+ return 0;
+}
+
+/**
+ * xread - force read of a certain number of bytes
+ * @v9ses: session info structure
+ * @ptr: pointer to buffer
+ * @sz: number of bytes to read
+ *
+ * Chuck Cranor CS-533 project1
+ */
+
+static int xread(struct v9fs_session_info *v9ses, void *ptr, unsigned long sz)
+{
+ int rd = 0;
+ int ret = 0;
+ while (rd < sz) {
+ ret = v9ses->transport->read(v9ses->transport, ptr, sz - rd);
+ if (ret <= 0) {
+ dprintk(DEBUG_ERROR, "xread errno %d\n", ret);
+ return ret;
+ }
+ rd += ret;
+ ptr += ret;
+ }
+ return (rd);
+}
+
+/**
+ * read_message - read a full 9P2000 fcall packet
+ * @v9ses: session info structure
+ * @rcall: fcall structure to read into
+ * @rcalllen: size of fcall buffer
+ *
+ */
+
+static int
+read_message(struct v9fs_session_info *v9ses,
+ struct v9fs_fcall *rcall, int rcalllen)
+{
+ unsigned char buf[4];
+ void *data;
+ int size = 0;
+ int res = 0;
+
+ res = xread(v9ses, buf, sizeof(buf));
+ if (res < 0) {
+ dprintk(DEBUG_ERROR,
+ "Reading of count field failed returned: %d\n", res);
+ return res;
+ }
+
+ if (res < 4) {
+ dprintk(DEBUG_ERROR,
+ "Reading of count field failed returned: %d\n", res);
+ return -EIO;
+ }
+
+ size = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
+ dprintk(DEBUG_MUX, "got a packet count: %d\n", size);
+
+ /* adjust for the four bytes of size */
+ size -= 4;
+
+ if (size > v9ses->maxdata) {
+ dprintk(DEBUG_ERROR, "packet too big: %d\n", size);
+ return -E2BIG;
+ }
+
+ data = kmalloc(size, GFP_KERNEL);
+ if (!data) {
+ eprintk(KERN_WARNING, "out of memory\n");
+ return -ENOMEM;
+ }
+
+ res = xread(v9ses, data, size);
+ if (res < size) {
+ dprintk(DEBUG_ERROR, "Reading of fcall failed returned: %d\n",
+ res);
+ kfree(data);
+ return res;
+ }
+
+ /* we now have an in-memory string that is the reply.
+ * deserialize it. There is very little to go wrong at this point
+ * save for v9fs_alloc errors.
+ */
+ res = v9fs_deserialize_fcall(v9ses, size, data, v9ses->maxdata,
+ rcall, rcalllen);
+
+ kfree(data);
+
+ if (res < 0)
+ return res;
+
+ return 0;
+}
+
+/**
+ * v9fs_recv - receive an RPC response for a particular tag
+ * @v9ses: session info structure
+ * @req: RPC request structure
+ *
+ */
+
+static int v9fs_recv(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
+{
+ int ret = 0;
+
+ dprintk(DEBUG_MUX, "waiting for response: %d\n", req->tcall->tag);
+ ret = wait_event_interruptible(v9ses->read_wait,
+ ((v9ses->transport->status != Connected) ||
+ (req->rcall != 0) || dprintcond(v9ses, req)));
+
+ dprintk(DEBUG_MUX, "got it: rcall %p\n", req->rcall);
+ if (v9ses->transport->status == Disconnected)
+ return -ECONNRESET;
+
+ if (ret == 0) {
+ spin_lock(&v9ses->muxlock);
+ list_del(&req->next);
+ spin_unlock(&v9ses->muxlock);
+ }
+
+ return ret;
+}
+
+/**
+ * v9fs_send - send a 9P request
+ * @v9ses: session info structure
+ * @req: RPC request to send
+ *
+ */
+
+static int v9fs_send(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
+{
+ int ret = -1;
+ void *data = NULL;
+ struct v9fs_fcall *tcall = req->tcall;
+
+ data = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ tcall->size = 0; /* enforce size recalculation */
+ ret =
+ v9fs_serialize_fcall(v9ses, tcall, data,
+ v9ses->maxdata + V9FS_IOHDRSZ);
+ if (ret < 0)
+ goto free_data;
+
+ spin_lock(&v9ses->muxlock);
+ list_add(&req->next, &v9ses->mux_fcalls);
+ spin_unlock(&v9ses->muxlock);
+
+ dprintk(DEBUG_MUX, "sending message: tag %d size %d\n", tcall->tag,
+ tcall->size);
+ ret = v9ses->transport->write(v9ses->transport, data, tcall->size);
+
+ if (ret != tcall->size) {
+ spin_lock(&v9ses->muxlock);
+ list_del(&req->next);
+ kfree(req->rcall);
+
+ spin_unlock(&v9ses->muxlock);
+ if (ret >= 0)
+ ret = -EREMOTEIO;
+ } else
+ ret = 0;
+
+ free_data:
+ kfree(data);
+ return ret;
+}
+
+/**
+ * v9fs_mux_rpc - send a request, receive a response
+ * @v9ses: session info structure
+ * @tcall: fcall to send
+ * @rcall: buffer to place response into
+ *
+ */
+
+long
+v9fs_mux_rpc(struct v9fs_session_info *v9ses, struct v9fs_fcall *tcall,
+ struct v9fs_fcall **rcall)
+{
+ int tid = -1;
+ struct v9fs_fcall *fcall = NULL;
+ struct v9fs_rpcreq req;
+ int ret = -1;
+
+ if (!v9ses)
+ return -EINVAL;
+
+ if (rcall)
+ *rcall = NULL;
+
+ if (tcall->id != TVERSION) {
+ tid = v9fs_get_idpool(&v9ses->tidpool);
+ if (tid < 0)
+ return -ENOMEM;
+ }
+
+ tcall->tag = tid;
+
+ req.tcall = tcall;
+ req.rcall = NULL;
+
+ ret = v9fs_send(v9ses, &req);
+
+ if (ret < 0) {
+ if (tcall->id != TVERSION)
+ v9fs_put_idpool(tid, &v9ses->tidpool);
+ dprintk(DEBUG_MUX, "error %d\n", ret);
+ return ret;
+ }
+
+ ret = v9fs_recv(v9ses, &req);
+
+ fcall = req.rcall;
+
+ dprintk(DEBUG_MUX, "received: tag=%x, ret=%d\n", tcall->tag, ret);
+ if (ret == -ERESTARTSYS) {
+ if (v9ses->transport->status != Disconnected
+ && tcall->id != TFLUSH) {
+ unsigned long flags;
+
+ dprintk(DEBUG_MUX, "flushing the tag: %d\n",
+ tcall->tag);
+ clear_thread_flag(TIF_SIGPENDING);
+ v9fs_t_flush(v9ses, tcall->tag);
+ spin_lock_irqsave(&current->sighand->siglock, flags);
+ recalc_sigpending();
+ spin_unlock_irqrestore(&current->sighand->siglock,
+ flags);
+ dprintk(DEBUG_MUX, "flushing done\n");
+ }
+
+ goto release_req;
+ } else if (ret < 0)
+ goto release_req;
+
+ if (!fcall)
+ ret = -EIO;
+ else {
+ if (fcall->id == RERROR) {
+ ret = v9fs_errstr2errno(fcall->params.rerror.error);
+ if (ret == 0) { /* string match failed */
+ if (fcall->params.rerror.errno)
+ ret = -(fcall->params.rerror.errno);
+ else
+ ret = -ESERVERFAULT;
+ }
+ } else if (fcall->id != tcall->id + 1) {
+ dprintk(DEBUG_ERROR,
+ "fcall mismatch: expected %d, got %d\n",
+ tcall->id + 1, fcall->id);
+ ret = -EIO;
+ }
+ }
+
+ release_req:
+ if (tcall->id != TVERSION)
+ v9fs_put_idpool(tid, &v9ses->tidpool);
+ if (rcall)
+ *rcall = fcall;
+ else
+ kfree(fcall);
+
+ return ret;
+}
+
+/**
+ * v9fs_recvproc - kproc to handle demultiplexing responses
+ * @data: session info structure
+ *
+ */
+
+static int v9fs_recvproc(void *data)
+{
+ struct v9fs_session_info *v9ses = (struct v9fs_session_info *)data;
+ struct v9fs_fcall *rcall = NULL;
+ struct v9fs_rpcreq *rptr;
+ struct v9fs_rpcreq *req;
+ struct v9fs_rpcreq *rreq;
+ int err = 0;
+
+ allow_signal(SIGKILL);
+ set_current_state(TASK_INTERRUPTIBLE);
+ complete(&v9ses->proccmpl);
+ while (!kthread_should_stop() && err >= 0) {
+ req = rptr = rreq = NULL;
+
+ rcall = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
+ if (!rcall) {
+ eprintk(KERN_ERR, "no memory for buffers\n");
+ break;
+ }
+
+ err = read_message(v9ses, rcall, v9ses->maxdata + V9FS_IOHDRSZ);
+ if (err < 0) {
+ kfree(rcall);
+ break;
+ }
+ spin_lock(&v9ses->muxlock);
+ list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
+ if (rreq->tcall->tag == rcall->tag) {
+ req = rreq;
+ req->rcall = rcall;
+ break;
+ }
+ }
+
+ if (req && (req->tcall->id == TFLUSH)) {
+ struct v9fs_rpcreq *treq = NULL;
+ list_for_each_entry_safe(treq, rptr, &v9ses->mux_fcalls, next) {
+ if (treq->tcall->tag ==
+ req->tcall->params.tflush.oldtag) {
+ list_del(&rptr->next);
+ kfree(treq->rcall);
+ break;
+ }
+ }
+ }
+
+ spin_unlock(&v9ses->muxlock);
+
+ if (!req) {
+ dprintk(DEBUG_ERROR,
+ "unexpected response: id %d tag %d\n",
+ rcall->id, rcall->tag);
+
+ kfree(rcall);
+ }
+
+ wake_up_all(&v9ses->read_wait);
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+
+ /* Inform all pending processes about the failure */
+ wake_up_all(&v9ses->read_wait);
+
+ if (signal_pending(current))
+ complete(&v9ses->proccmpl);
+
+ dprintk(DEBUG_MUX, "recvproc: end\n");
+ v9ses->recvproc = NULL;
+
+ return err >= 0;
+}
+
+/**
+ * v9fs_mux_init - initialize multiplexer (spawn kproc)
+ * @v9ses: session info structure
+ * @dev_name: mount device information (to create unique kproc)
+ *
+ */
+
+int v9fs_mux_init(struct v9fs_session_info *v9ses, const char *dev_name)
+{
+ char procname[60];
+
+ strncpy(procname, dev_name, sizeof(procname));
+ procname[sizeof(procname) - 1] = 0;
+
+ init_waitqueue_head(&v9ses->read_wait);
+ init_completion(&v9ses->fcread);
+ init_completion(&v9ses->proccmpl);
+ spin_lock_init(&v9ses->muxlock);
+ INIT_LIST_HEAD(&v9ses->mux_fcalls);
+ v9ses->recvproc = NULL;
+ v9ses->curfcall = NULL;
+
+ v9ses->recvproc = kthread_create(v9fs_recvproc, v9ses,
+ "v9fs_recvproc %s", procname);
+
+ if (IS_ERR(v9ses->recvproc)) {
+ eprintk(KERN_ERR, "cannot create receiving thread\n");
+ v9fs_session_close(v9ses);
+ return -ECONNABORTED;
+ }
+
+ wake_up_process(v9ses->recvproc);
+ wait_for_completion(&v9ses->proccmpl);
+
+ return 0;
+}
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