fs/cifs/transport.c - linux/kernel/git/torvalds/linux - Git at Google

 /*
  *   fs/cifs/transport.c
  *
  *   Copyright (C) International Business Machines  Corp., 2002,2005
  *   Author(s): Steve French (sfrench@us.ibm.com)
  *
  *   This library is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU Lesser General Public License as published
  *   by the Free Software Foundation; either version 2.1 of the License, or
  *   (at your option) any later version.
  *
  *   This library 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 Lesser General Public License for more details.
  *
  *   You should have received a copy of the GNU Lesser General Public License
  *   along with this library; if not, write to the Free Software
  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */

 #include <linux/fs.h>
 #include <linux/list.h>
 #include <linux/wait.h>
 #include <linux/net.h>
 #include <linux/delay.h>
 #include <asm/uaccess.h>
 #include <asm/processor.h>
 #include <linux/mempool.h>
 #include "cifspdu.h"
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"

 extern mempool_t *cifs_mid_poolp;
 extern kmem_cache_t *cifs_oplock_cachep;

 static struct mid_q_entry *
 AllocMidQEntry(struct smb_hdr *smb_buffer, struct cifsSesInfo *ses)
 {
 	struct mid_q_entry *temp;

 	if (ses == NULL) {
 		cERROR(1, ("Null session passed in to AllocMidQEntry"));
 		return NULL;
 	}
 	if (ses->server == NULL) {
 		cERROR(1, ("Null TCP session in AllocMidQEntry"));
 		return NULL;
 	}

 	temp = (struct mid_q_entry *) mempool_alloc(cifs_mid_poolp,SLAB_KERNEL | SLAB_NOFS);
 	if (temp == NULL)
 		return temp;
 	else {
 		memset(temp, 0, sizeof (struct mid_q_entry));
 		temp->mid = smb_buffer->Mid;	/* always LE */
 		temp->pid = current->pid;
 		temp->command = smb_buffer->Command;
 		cFYI(1, ("For smb_command %d", temp->command));
 		do_gettimeofday(&temp->when_sent);
 		temp->ses = ses;
 		temp->tsk = current;
 	}

 	spin_lock(&GlobalMid_Lock);
 	list_add_tail(&temp->qhead, &ses->server->pending_mid_q);
 	atomic_inc(&midCount);
 	temp->midState = MID_REQUEST_ALLOCATED;
 	spin_unlock(&GlobalMid_Lock);
 	return temp;
 }

 static void
 DeleteMidQEntry(struct mid_q_entry *midEntry)
 {
 	spin_lock(&GlobalMid_Lock);
 	midEntry->midState = MID_FREE;
 	list_del(&midEntry->qhead);
 	atomic_dec(&midCount);
 	spin_unlock(&GlobalMid_Lock);
 	if(midEntry->largeBuf)
 		cifs_buf_release(midEntry->resp_buf);
 	else
 		cifs_small_buf_release(midEntry->resp_buf);
 	mempool_free(midEntry, cifs_mid_poolp);
 }

 struct oplock_q_entry *
 AllocOplockQEntry(struct inode * pinode, __u16 fid, struct cifsTconInfo * tcon)
 {
 	struct oplock_q_entry *temp;
 	if ((pinode== NULL) || (tcon == NULL)) {
 		cERROR(1, ("Null parms passed to AllocOplockQEntry"));
 		return NULL;
 	}
 	temp = (struct oplock_q_entry *) kmem_cache_alloc(cifs_oplock_cachep,
 						       SLAB_KERNEL);
 	if (temp == NULL)
 		return temp;
 	else {
 		temp->pinode = pinode;
 		temp->tcon = tcon;
 		temp->netfid = fid;
 		spin_lock(&GlobalMid_Lock);
 		list_add_tail(&temp->qhead, &GlobalOplock_Q);
 		spin_unlock(&GlobalMid_Lock);
 	}
 	return temp;

 }

 void DeleteOplockQEntry(struct oplock_q_entry * oplockEntry)
 {
 	spin_lock(&GlobalMid_Lock);
     /* should we check if list empty first? */
 	list_del(&oplockEntry->qhead);
 	spin_unlock(&GlobalMid_Lock);
 	kmem_cache_free(cifs_oplock_cachep, oplockEntry);
 }

 int
 smb_send(struct socket *ssocket, struct smb_hdr *smb_buffer,
 	 unsigned int smb_buf_length, struct sockaddr *sin)
 {
 	int rc = 0;
 	int i = 0;
 	struct msghdr smb_msg;
 	struct kvec iov;
 	unsigned len = smb_buf_length + 4;

 	if(ssocket == NULL)
 		return -ENOTSOCK; /* BB eventually add reconnect code here */
 	iov.iov_base = smb_buffer;
 	iov.iov_len = len;

 	smb_msg.msg_name = sin;
 	smb_msg.msg_namelen = sizeof (struct sockaddr);
 	smb_msg.msg_control = NULL;
 	smb_msg.msg_controllen = 0;
 	smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL; /* BB add more flags?*/

 	/* smb header is converted in header_assemble. bcc and rest of SMB word
 	   area, and byte area if necessary, is converted to littleendian in
 	   cifssmb.c and RFC1001 len is converted to bigendian in smb_send
 	   Flags2 is converted in SendReceive */

 	smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
 	cFYI(1, ("Sending smb of length %d ", smb_buf_length));
 	dump_smb(smb_buffer, len);

 	while (len > 0) {
 		rc = kernel_sendmsg(ssocket, &smb_msg, &iov, 1, len);
 		if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
 			i++;
 			if(i > 60) {
 				cERROR(1,
 				   ("sends on sock %p stuck for 30 seconds",
 				    ssocket));
 				rc = -EAGAIN;
 				break;
 			}
 			msleep(500);
 			continue;
 		}
 		if (rc < 0)
 			break;
 		iov.iov_base += rc;
 		iov.iov_len -= rc;
 		len -= rc;
 	}

 	if (rc < 0) {
 		cERROR(1,("Error %d sending data on socket to server.", rc));
 	} else {
 		rc = 0;
 	}

 	return rc;
 }

 #ifdef CIFS_EXPERIMENTAL
 /* BB finish off this function, adding support for writing set of pages as iovec */
 /* and also adding support for operations that need to parse the response smb    */

 int
 smb_sendv(struct socket *ssocket, struct smb_hdr *smb_buffer,
 	 unsigned int smb_buf_length, struct kvec * write_vector
 	  /* page list */, struct sockaddr *sin)
 {
 	int rc = 0;
 	int i = 0;
 	struct msghdr smb_msg;
 	number_of_pages += 1; /* account for SMB header */
 	struct kvec * piov  = kmalloc(number_of_pages * sizeof(struct kvec));
 	unsigned len = smb_buf_length + 4;

 	if(ssocket == NULL)
 		return -ENOTSOCK; /* BB eventually add reconnect code here */
 	iov.iov_base = smb_buffer;
 	iov.iov_len = len;

 	smb_msg.msg_name = sin;
 	smb_msg.msg_namelen = sizeof (struct sockaddr);
 	smb_msg.msg_control = NULL;
 	smb_msg.msg_controllen = 0;
 	smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL; /* BB add more flags?*/

 	/* smb header is converted in header_assemble. bcc and rest of SMB word
 	   area, and byte area if necessary, is converted to littleendian in
 	   cifssmb.c and RFC1001 len is converted to bigendian in smb_send
 	   Flags2 is converted in SendReceive */

 	smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
 	cFYI(1, ("Sending smb of length %d ", smb_buf_length));
 	dump_smb(smb_buffer, len);

 	while (len > 0) {
 		rc = kernel_sendmsg(ssocket, &smb_msg, &iov, number_of_pages,
 				    len);
 		if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
 			i++;
 			if(i > 60) {
 				cERROR(1,
 				   ("sends on sock %p stuck for 30 seconds",
 				    ssocket));
 				rc = -EAGAIN;
 				break;
 			}
 			msleep(500);
 			continue;
 		}
 		if (rc < 0)
 			break;
 		iov.iov_base += rc;
 		iov.iov_len -= rc;
 		len -= rc;
 	}

 	if (rc < 0) {
 		cERROR(1,("Error %d sending data on socket to server.", rc));
 	} else {
 		rc = 0;
 	}

 	return rc;
 }


 int
 CIFSSendRcv(const unsigned int xid, struct cifsSesInfo *ses,
 	    struct smb_hdr *in_buf, struct kvec * write_vector /* page list */, int *pbytes_returned, const int long_op)
 {
 	int rc = 0;
 	unsigned long timeout = 15 * HZ;
 	struct mid_q_entry *midQ = NULL;

 	if (ses == NULL) {
 		cERROR(1,("Null smb session"));
 		return -EIO;
 	}
 	if(ses->server == NULL) {
 		cERROR(1,("Null tcp session"));
 		return -EIO;
 	}
 	if(pbytes_returned == NULL)
 		return -EIO;
 	else
 		*pbytes_returned = 0;


 	if(ses->server->tcpStatus == CIFS_EXITING)
 		return -ENOENT;

 	/* Ensure that we do not send more than 50 overlapping requests
 	   to the same server. We may make this configurable later or
 	   use ses->maxReq */
 	if(long_op == -1) {
 		/* oplock breaks must not be held up */
 		atomic_inc(&ses->server->inFlight);
 	} else {
 		spin_lock(&GlobalMid_Lock);
 		while(1) {
 			if(atomic_read(&ses->server->inFlight) >= cifs_max_pending){
 				spin_unlock(&GlobalMid_Lock);
 				wait_event(ses->server->request_q,
 					atomic_read(&ses->server->inFlight)
 					 < cifs_max_pending);
 				spin_lock(&GlobalMid_Lock);
 			} else {
 				if(ses->server->tcpStatus == CifsExiting) {
 					spin_unlock(&GlobalMid_Lock);
 					return -ENOENT;
 				}

 			/* can not count locking commands against total since
 			   they are allowed to block on server */

 				if(long_op < 3) {
 				/* update # of requests on the wire to server */
 					atomic_inc(&ses->server->inFlight);
 				}
 				spin_unlock(&GlobalMid_Lock);
 				break;
 			}
 		}
 	}
 	/* make sure that we sign in the same order that we send on this socket
 	   and avoid races inside tcp sendmsg code that could cause corruption
 	   of smb data */

 	down(&ses->server->tcpSem);

 	if (ses->server->tcpStatus == CifsExiting) {
 		rc = -ENOENT;
 		goto cifs_out_label;
 	} else if (ses->server->tcpStatus == CifsNeedReconnect) {
 		cFYI(1,("tcp session dead - return to caller to retry"));
 		rc = -EAGAIN;
 		goto cifs_out_label;
 	} else if (ses->status != CifsGood) {
 		/* check if SMB session is bad because we are setting it up */
 		if((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 			(in_buf->Command != SMB_COM_NEGOTIATE)) {
 			rc = -EAGAIN;
 			goto cifs_out_label;
 		} /* else ok - we are setting up session */
 	}
 	midQ = AllocMidQEntry(in_buf, ses);
 	if (midQ == NULL) {
 		up(&ses->server->tcpSem);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return -ENOMEM;
 	}

 	if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
 		up(&ses->server->tcpSem);
 		cERROR(1,
 		       ("Illegal length, greater than maximum frame, %d ",
 			in_buf->smb_buf_length));
 		DeleteMidQEntry(midQ);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return -EIO;
 	}

 	/* BB can we sign efficiently in this path? */
 	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);

 	midQ->midState = MID_REQUEST_SUBMITTED;
 /*	rc = smb_sendv(ses->server->ssocket, in_buf, in_buf->smb_buf_length,
 		       piovec,
 		       (struct sockaddr *) &(ses->server->addr.sockAddr));*/
 	if(rc < 0) {
 		DeleteMidQEntry(midQ);
 		up(&ses->server->tcpSem);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return rc;
 	} else
 		up(&ses->server->tcpSem);
 cifs_out_label:
 	if(midQ)
 	        DeleteMidQEntry(midQ);

 	if(long_op < 3) {
 		atomic_dec(&ses->server->inFlight);
 		wake_up(&ses->server->request_q);
 	}

 	return rc;
 }


 #endif /* CIFS_EXPERIMENTAL */

 int
 SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
 	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
 	    int *pbytes_returned, const int long_op)
 {
 	int rc = 0;
 	unsigned int receive_len;
 	unsigned long timeout;
 	struct mid_q_entry *midQ;

 	if (ses == NULL) {
 		cERROR(1,("Null smb session"));
 		return -EIO;
 	}
 	if(ses->server == NULL) {
 		cERROR(1,("Null tcp session"));
 		return -EIO;
 	}

 	if(ses->server->tcpStatus == CifsExiting)
 		return -ENOENT;

 	/* Ensure that we do not send more than 50 overlapping requests
 	   to the same server. We may make this configurable later or
 	   use ses->maxReq */
 	if(long_op == -1) {
 		/* oplock breaks must not be held up */
 		atomic_inc(&ses->server->inFlight);
 	} else {
 		spin_lock(&GlobalMid_Lock);
 		while(1) {
 			if(atomic_read(&ses->server->inFlight) >=
 					cifs_max_pending){
 				spin_unlock(&GlobalMid_Lock);
 				wait_event(ses->server->request_q,
 					atomic_read(&ses->server->inFlight)
 					 < cifs_max_pending);
 				spin_lock(&GlobalMid_Lock);
 			} else {
 				if(ses->server->tcpStatus == CifsExiting) {
 					spin_unlock(&GlobalMid_Lock);
 					return -ENOENT;
 				}

 			/* can not count locking commands against total since
 			   they are allowed to block on server */

 				if(long_op < 3) {
 				/* update # of requests on the wire to server */
 					atomic_inc(&ses->server->inFlight);
 				}
 				spin_unlock(&GlobalMid_Lock);
 				break;
 			}
 		}
 	}
 	/* make sure that we sign in the same order that we send on this socket
 	   and avoid races inside tcp sendmsg code that could cause corruption
 	   of smb data */

 	down(&ses->server->tcpSem);

 	if (ses->server->tcpStatus == CifsExiting) {
 		rc = -ENOENT;
 		goto out_unlock;
 	} else if (ses->server->tcpStatus == CifsNeedReconnect) {
 		cFYI(1,("tcp session dead - return to caller to retry"));
 		rc = -EAGAIN;
 		goto out_unlock;
 	} else if (ses->status != CifsGood) {
 		/* check if SMB session is bad because we are setting it up */
 		if((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
 			(in_buf->Command != SMB_COM_NEGOTIATE)) {
 			rc = -EAGAIN;
 			goto out_unlock;
 		} /* else ok - we are setting up session */
 	}
 	midQ = AllocMidQEntry(in_buf, ses);
 	if (midQ == NULL) {
 		up(&ses->server->tcpSem);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return -ENOMEM;
 	}

 	if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
 		up(&ses->server->tcpSem);
 		cERROR(1,
 		       ("Illegal length, greater than maximum frame, %d ",
 			in_buf->smb_buf_length));
 		DeleteMidQEntry(midQ);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return -EIO;
 	}

 	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);

 	midQ->midState = MID_REQUEST_SUBMITTED;
 	rc = smb_send(ses->server->ssocket, in_buf, in_buf->smb_buf_length,
 		      (struct sockaddr *) &(ses->server->addr.sockAddr));
 	if(rc < 0) {
 		DeleteMidQEntry(midQ);
 		up(&ses->server->tcpSem);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return rc;
 	} else
 		up(&ses->server->tcpSem);
 	if (long_op == -1)
 		goto cifs_no_response_exit;
 	else if (long_op == 2) /* writes past end of file can take loong time */
 		timeout = 300 * HZ;
 	else if (long_op == 1)
 		timeout = 45 * HZ; /* should be greater than
 			servers oplock break timeout (about 43 seconds) */
 	else if (long_op > 2) {
 		timeout = MAX_SCHEDULE_TIMEOUT;
 	} else
 		timeout = 15 * HZ;
 	/* wait for 15 seconds or until woken up due to response arriving or
 	   due to last connection to this server being unmounted */
 	if (signal_pending(current)) {
 		/* if signal pending do not hold up user for full smb timeout
 		but we still give response a change to complete */
 		timeout = 2 * HZ;
 	}

 	/* No user interrupts in wait - wreaks havoc with performance */
 	if(timeout != MAX_SCHEDULE_TIMEOUT) {
 		timeout += jiffies;
 		wait_event(ses->server->response_q,
 			(!(midQ->midState & MID_REQUEST_SUBMITTED)) ||
 			time_after(jiffies, timeout) ||
 			((ses->server->tcpStatus != CifsGood) &&
 			 (ses->server->tcpStatus != CifsNew)));
 	} else {
 		wait_event(ses->server->response_q,
 			(!(midQ->midState & MID_REQUEST_SUBMITTED)) ||
 			((ses->server->tcpStatus != CifsGood) &&
 			 (ses->server->tcpStatus != CifsNew)));
 	}

 	spin_lock(&GlobalMid_Lock);
 	if (midQ->resp_buf) {
 		spin_unlock(&GlobalMid_Lock);
 		receive_len = be32_to_cpu(*(__be32 *)midQ->resp_buf);
 	} else {
 		cERROR(1,("No response buffer"));
 		if(midQ->midState == MID_REQUEST_SUBMITTED) {
 			if(ses->server->tcpStatus == CifsExiting)
 				rc = -EHOSTDOWN;
 			else {
 				ses->server->tcpStatus = CifsNeedReconnect;
 				midQ->midState = MID_RETRY_NEEDED;
 			}
 		}

 		if (rc != -EHOSTDOWN) {
 			if(midQ->midState == MID_RETRY_NEEDED) {
 				rc = -EAGAIN;
 				cFYI(1,("marking request for retry"));
 			} else {
 				rc = -EIO;
 			}
 		}
 		spin_unlock(&GlobalMid_Lock);
 		DeleteMidQEntry(midQ);
 		/* If not lock req, update # of requests on wire to server */
 		if(long_op < 3) {
 			atomic_dec(&ses->server->inFlight);
 			wake_up(&ses->server->request_q);
 		}
 		return rc;
 	}

 	if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
 		cERROR(1, ("Frame too large received.  Length: %d  Xid: %d",
 			receive_len, xid));
 		rc = -EIO;
 	} else {		/* rcvd frame is ok */

 		if (midQ->resp_buf && out_buf
 		    && (midQ->midState == MID_RESPONSE_RECEIVED)) {
 			out_buf->smb_buf_length = receive_len;
 			memcpy((char *)out_buf + 4,
 			       (char *)midQ->resp_buf + 4,
 			       receive_len);

 			dump_smb(out_buf, 92);
 			/* convert the length into a more usable form */
 			if((receive_len > 24) &&
 			   (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
 					SECMODE_SIGN_ENABLED))) {
 				rc = cifs_verify_signature(out_buf,
 						ses->server->mac_signing_key,
 						midQ->sequence_number+1);
 				if(rc) {
 					cERROR(1,("Unexpected SMB signature"));
 					/* BB FIXME add code to kill session */
 				}
 			}

 			*pbytes_returned = out_buf->smb_buf_length;

 			/* BB special case reconnect tid and uid here? */
 			rc = map_smb_to_linux_error(out_buf);

 			/* convert ByteCount if necessary */
 			if (receive_len >=
 			    sizeof (struct smb_hdr) -
 			    4 /* do not count RFC1001 header */  +
 			    (2 * out_buf->WordCount) + 2 /* bcc */ )
 				BCC(out_buf) = le16_to_cpu(BCC(out_buf));
 		} else {
 			rc = -EIO;
 			cFYI(1,("Bad MID state? "));
 		}
 	}
 cifs_no_response_exit:
 	DeleteMidQEntry(midQ);

 	if(long_op < 3) {
 		atomic_dec(&ses->server->inFlight);
 		wake_up(&ses->server->request_q);
 	}

 	return rc;

 out_unlock:
 	up(&ses->server->tcpSem);
 	/* If not lock req, update # of requests on wire to server */
 	if(long_op < 3) {
 		atomic_dec(&ses->server->inFlight);
 		wake_up(&ses->server->request_q);
 	}

 	return rc;
 }
	/*
	* fs/cifs/transport.c
	*
	* Copyright (C) International Business Machines Corp., 2002,2005
	* Author(s): Steve French (sfrench@us.ibm.com)
	*
	* This library is free software; you can redistribute it and/or modify
	* it under the terms of the GNU Lesser General Public License as published
	* by the Free Software Foundation; either version 2.1 of the License, or
	* (at your option) any later version.
	*
	* This library 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 Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public License
	* along with this library; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/fs.h>
	#include <linux/list.h>
	#include <linux/wait.h>
	#include <linux/net.h>
	#include <linux/delay.h>
	#include <asm/uaccess.h>
	#include <asm/processor.h>
	#include <linux/mempool.h>
	#include "cifspdu.h"
	#include "cifsglob.h"
	#include "cifsproto.h"
	#include "cifs_debug.h"

	extern mempool_t *cifs_mid_poolp;
	extern kmem_cache_t *cifs_oplock_cachep;

	static struct mid_q_entry *
	AllocMidQEntry(struct smb_hdr smb_buffer, struct cifsSesInfo ses)
	{
	struct mid_q_entry *temp;

	if (ses == NULL) {
	cERROR(1, ("Null session passed in to AllocMidQEntry"));
	return NULL;
	}
	if (ses->server == NULL) {
	cERROR(1, ("Null TCP session in AllocMidQEntry"));
	return NULL;
	}

	temp = (struct mid_q_entry *) mempool_alloc(cifs_mid_poolp,SLAB_KERNEL \| SLAB_NOFS);
	if (temp == NULL)
	return temp;
	else {
	memset(temp, 0, sizeof (struct mid_q_entry));
	temp->mid = smb_buffer->Mid; /* always LE */
	temp->pid = current->pid;
	temp->command = smb_buffer->Command;
	cFYI(1, ("For smb_command %d", temp->command));
	do_gettimeofday(&temp->when_sent);
	temp->ses = ses;
	temp->tsk = current;
	}

	spin_lock(&GlobalMid_Lock);
	list_add_tail(&temp->qhead, &ses->server->pending_mid_q);
	atomic_inc(&midCount);
	temp->midState = MID_REQUEST_ALLOCATED;
	spin_unlock(&GlobalMid_Lock);
	return temp;
	}

	static void
	DeleteMidQEntry(struct mid_q_entry *midEntry)
	{
	spin_lock(&GlobalMid_Lock);
	midEntry->midState = MID_FREE;
	list_del(&midEntry->qhead);
	atomic_dec(&midCount);
	spin_unlock(&GlobalMid_Lock);
	if(midEntry->largeBuf)
	cifs_buf_release(midEntry->resp_buf);
	else
	cifs_small_buf_release(midEntry->resp_buf);
	mempool_free(midEntry, cifs_mid_poolp);
	}

	struct oplock_q_entry *
	AllocOplockQEntry(struct inode * pinode, __u16 fid, struct cifsTconInfo * tcon)
	{
	struct oplock_q_entry *temp;
	if ((pinode== NULL) \|\| (tcon == NULL)) {
	cERROR(1, ("Null parms passed to AllocOplockQEntry"));
	return NULL;
	}
	temp = (struct oplock_q_entry *) kmem_cache_alloc(cifs_oplock_cachep,
	SLAB_KERNEL);
	if (temp == NULL)
	return temp;
	else {
	temp->pinode = pinode;
	temp->tcon = tcon;
	temp->netfid = fid;
	spin_lock(&GlobalMid_Lock);
	list_add_tail(&temp->qhead, &GlobalOplock_Q);
	spin_unlock(&GlobalMid_Lock);
	}
	return temp;

	}

	void DeleteOplockQEntry(struct oplock_q_entry * oplockEntry)
	{
	spin_lock(&GlobalMid_Lock);
	/* should we check if list empty first? */
	list_del(&oplockEntry->qhead);
	spin_unlock(&GlobalMid_Lock);
	kmem_cache_free(cifs_oplock_cachep, oplockEntry);
	}

	int
	smb_send(struct socket ssocket, struct smb_hdr smb_buffer,
	unsigned int smb_buf_length, struct sockaddr *sin)
	{
	int rc = 0;
	int i = 0;
	struct msghdr smb_msg;
	struct kvec iov;
	unsigned len = smb_buf_length + 4;

	if(ssocket == NULL)
	return -ENOTSOCK; /* BB eventually add reconnect code here */
	iov.iov_base = smb_buffer;
	iov.iov_len = len;

	smb_msg.msg_name = sin;
	smb_msg.msg_namelen = sizeof (struct sockaddr);
	smb_msg.msg_control = NULL;
	smb_msg.msg_controllen = 0;
	smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL; /* BB add more flags?*/

	/* smb header is converted in header_assemble. bcc and rest of SMB word
	area, and byte area if necessary, is converted to littleendian in
	cifssmb.c and RFC1001 len is converted to bigendian in smb_send
	Flags2 is converted in SendReceive */

	smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
	cFYI(1, ("Sending smb of length %d ", smb_buf_length));
	dump_smb(smb_buffer, len);

	while (len > 0) {
	rc = kernel_sendmsg(ssocket, &smb_msg, &iov, 1, len);
	if ((rc == -ENOSPC) \|\| (rc == -EAGAIN)) {
	i++;
	if(i > 60) {
	cERROR(1,
	("sends on sock %p stuck for 30 seconds",
	ssocket));
	rc = -EAGAIN;
	break;
	}
	msleep(500);
	continue;
	}
	if (rc < 0)
	break;
	iov.iov_base += rc;
	iov.iov_len -= rc;
	len -= rc;
	}

	if (rc < 0) {
	cERROR(1,("Error %d sending data on socket to server.", rc));
	} else {
	rc = 0;
	}

	return rc;
	}

	#ifdef CIFS_EXPERIMENTAL
	/* BB finish off this function, adding support for writing set of pages as iovec */
	/* and also adding support for operations that need to parse the response smb */

	int
	smb_sendv(struct socket ssocket, struct smb_hdr smb_buffer,
	unsigned int smb_buf_length, struct kvec * write_vector
	/* page list /, struct sockaddr sin)
	{
	int rc = 0;
	int i = 0;
	struct msghdr smb_msg;
	number_of_pages += 1; /* account for SMB header */
	struct kvec * piov = kmalloc(number_of_pages * sizeof(struct kvec));
	unsigned len = smb_buf_length + 4;

	if(ssocket == NULL)
	return -ENOTSOCK; /* BB eventually add reconnect code here */
	iov.iov_base = smb_buffer;
	iov.iov_len = len;

	smb_msg.msg_name = sin;
	smb_msg.msg_namelen = sizeof (struct sockaddr);
	smb_msg.msg_control = NULL;
	smb_msg.msg_controllen = 0;
	smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL; /* BB add more flags?*/

	/* smb header is converted in header_assemble. bcc and rest of SMB word
	area, and byte area if necessary, is converted to littleendian in
	cifssmb.c and RFC1001 len is converted to bigendian in smb_send
	Flags2 is converted in SendReceive */

	smb_buffer->smb_buf_length = cpu_to_be32(smb_buffer->smb_buf_length);
	cFYI(1, ("Sending smb of length %d ", smb_buf_length));
	dump_smb(smb_buffer, len);

	while (len > 0) {
	rc = kernel_sendmsg(ssocket, &smb_msg, &iov, number_of_pages,
	len);
	if ((rc == -ENOSPC) \|\| (rc == -EAGAIN)) {
	i++;
	if(i > 60) {
	cERROR(1,
	("sends on sock %p stuck for 30 seconds",
	ssocket));
	rc = -EAGAIN;
	break;
	}
	msleep(500);
	continue;
	}
	if (rc < 0)
	break;
	iov.iov_base += rc;
	iov.iov_len -= rc;
	len -= rc;
	}

	if (rc < 0) {
	cERROR(1,("Error %d sending data on socket to server.", rc));
	} else {
	rc = 0;
	}

	return rc;
	}


	int
	CIFSSendRcv(const unsigned int xid, struct cifsSesInfo *ses,
	struct smb_hdr in_buf, struct kvec write_vector /* page list /, int pbytes_returned, const int long_op)
	{
	int rc = 0;
	unsigned long timeout = 15 * HZ;
	struct mid_q_entry *midQ = NULL;

	if (ses == NULL) {
	cERROR(1,("Null smb session"));
	return -EIO;
	}
	if(ses->server == NULL) {
	cERROR(1,("Null tcp session"));
	return -EIO;
	}
	if(pbytes_returned == NULL)
	return -EIO;
	else
	*pbytes_returned = 0;



	if(ses->server->tcpStatus == CIFS_EXITING)
	return -ENOENT;

	/* Ensure that we do not send more than 50 overlapping requests
	to the same server. We may make this configurable later or
	use ses->maxReq */
	if(long_op == -1) {
	/* oplock breaks must not be held up */
	atomic_inc(&ses->server->inFlight);
	} else {
	spin_lock(&GlobalMid_Lock);
	while(1) {
	if(atomic_read(&ses->server->inFlight) >= cifs_max_pending){
	spin_unlock(&GlobalMid_Lock);
	wait_event(ses->server->request_q,
	atomic_read(&ses->server->inFlight)
	< cifs_max_pending);
	spin_lock(&GlobalMid_Lock);
	} else {
	if(ses->server->tcpStatus == CifsExiting) {
	spin_unlock(&GlobalMid_Lock);
	return -ENOENT;
	}

	/* can not count locking commands against total since
	they are allowed to block on server */

	if(long_op < 3) {
	/* update # of requests on the wire to server */
	atomic_inc(&ses->server->inFlight);
	}
	spin_unlock(&GlobalMid_Lock);
	break;
	}
	}
	}
	/* make sure that we sign in the same order that we send on this socket
	and avoid races inside tcp sendmsg code that could cause corruption
	of smb data */

	down(&ses->server->tcpSem);

	if (ses->server->tcpStatus == CifsExiting) {
	rc = -ENOENT;
	goto cifs_out_label;
	} else if (ses->server->tcpStatus == CifsNeedReconnect) {
	cFYI(1,("tcp session dead - return to caller to retry"));
	rc = -EAGAIN;
	goto cifs_out_label;
	} else if (ses->status != CifsGood) {
	/* check if SMB session is bad because we are setting it up */
	if((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
	(in_buf->Command != SMB_COM_NEGOTIATE)) {
	rc = -EAGAIN;
	goto cifs_out_label;
	} /* else ok - we are setting up session */
	}
	midQ = AllocMidQEntry(in_buf, ses);
	if (midQ == NULL) {
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return -ENOMEM;
	}

	if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
	up(&ses->server->tcpSem);
	cERROR(1,
	("Illegal length, greater than maximum frame, %d ",
	in_buf->smb_buf_length));
	DeleteMidQEntry(midQ);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return -EIO;
	}

	/* BB can we sign efficiently in this path? */
	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);

	midQ->midState = MID_REQUEST_SUBMITTED;
	/* rc = smb_sendv(ses->server->ssocket, in_buf, in_buf->smb_buf_length,
	piovec,
	(struct sockaddr ) &(ses->server->addr.sockAddr));/
	if(rc < 0) {
	DeleteMidQEntry(midQ);
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return rc;
	} else
	up(&ses->server->tcpSem);
	cifs_out_label:
	if(midQ)
	DeleteMidQEntry(midQ);

	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}

	return rc;
	}


	#endif /* CIFS_EXPERIMENTAL */

	int
	SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
	struct smb_hdr in_buf, struct smb_hdr out_buf,
	int *pbytes_returned, const int long_op)
	{
	int rc = 0;
	unsigned int receive_len;
	unsigned long timeout;
	struct mid_q_entry *midQ;

	if (ses == NULL) {
	cERROR(1,("Null smb session"));
	return -EIO;
	}
	if(ses->server == NULL) {
	cERROR(1,("Null tcp session"));
	return -EIO;
	}

	if(ses->server->tcpStatus == CifsExiting)
	return -ENOENT;

	/* Ensure that we do not send more than 50 overlapping requests
	to the same server. We may make this configurable later or
	use ses->maxReq */
	if(long_op == -1) {
	/* oplock breaks must not be held up */
	atomic_inc(&ses->server->inFlight);
	} else {
	spin_lock(&GlobalMid_Lock);
	while(1) {
	if(atomic_read(&ses->server->inFlight) >=
	cifs_max_pending){
	spin_unlock(&GlobalMid_Lock);
	wait_event(ses->server->request_q,
	atomic_read(&ses->server->inFlight)
	< cifs_max_pending);
	spin_lock(&GlobalMid_Lock);
	} else {
	if(ses->server->tcpStatus == CifsExiting) {
	spin_unlock(&GlobalMid_Lock);
	return -ENOENT;
	}

	/* can not count locking commands against total since
	they are allowed to block on server */

	if(long_op < 3) {
	/* update # of requests on the wire to server */
	atomic_inc(&ses->server->inFlight);
	}
	spin_unlock(&GlobalMid_Lock);
	break;
	}
	}
	}
	/* make sure that we sign in the same order that we send on this socket
	and avoid races inside tcp sendmsg code that could cause corruption
	of smb data */

	down(&ses->server->tcpSem);

	if (ses->server->tcpStatus == CifsExiting) {
	rc = -ENOENT;
	goto out_unlock;
	} else if (ses->server->tcpStatus == CifsNeedReconnect) {
	cFYI(1,("tcp session dead - return to caller to retry"));
	rc = -EAGAIN;
	goto out_unlock;
	} else if (ses->status != CifsGood) {
	/* check if SMB session is bad because we are setting it up */
	if((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
	(in_buf->Command != SMB_COM_NEGOTIATE)) {
	rc = -EAGAIN;
	goto out_unlock;
	} /* else ok - we are setting up session */
	}
	midQ = AllocMidQEntry(in_buf, ses);
	if (midQ == NULL) {
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return -ENOMEM;
	}

	if (in_buf->smb_buf_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
	up(&ses->server->tcpSem);
	cERROR(1,
	("Illegal length, greater than maximum frame, %d ",
	in_buf->smb_buf_length));
	DeleteMidQEntry(midQ);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return -EIO;
	}

	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);

	midQ->midState = MID_REQUEST_SUBMITTED;
	rc = smb_send(ses->server->ssocket, in_buf, in_buf->smb_buf_length,
	(struct sockaddr *) &(ses->server->addr.sockAddr));
	if(rc < 0) {
	DeleteMidQEntry(midQ);
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return rc;
	} else
	up(&ses->server->tcpSem);
	if (long_op == -1)
	goto cifs_no_response_exit;
	else if (long_op == 2) /* writes past end of file can take loong time */
	timeout = 300 * HZ;
	else if (long_op == 1)
	timeout = 45 * HZ; /* should be greater than
	servers oplock break timeout (about 43 seconds) */
	else if (long_op > 2) {
	timeout = MAX_SCHEDULE_TIMEOUT;
	} else
	timeout = 15 * HZ;
	/* wait for 15 seconds or until woken up due to response arriving or
	due to last connection to this server being unmounted */
	if (signal_pending(current)) {
	/* if signal pending do not hold up user for full smb timeout
	but we still give response a change to complete */
	timeout = 2 * HZ;
	}

	/* No user interrupts in wait - wreaks havoc with performance */
	if(timeout != MAX_SCHEDULE_TIMEOUT) {
	timeout += jiffies;
	wait_event(ses->server->response_q,
	(!(midQ->midState & MID_REQUEST_SUBMITTED)) \|\|
	time_after(jiffies, timeout) \|\|
	((ses->server->tcpStatus != CifsGood) &&
	(ses->server->tcpStatus != CifsNew)));
	} else {
	wait_event(ses->server->response_q,
	(!(midQ->midState & MID_REQUEST_SUBMITTED)) \|\|
	((ses->server->tcpStatus != CifsGood) &&
	(ses->server->tcpStatus != CifsNew)));
	}

	spin_lock(&GlobalMid_Lock);
	if (midQ->resp_buf) {
	spin_unlock(&GlobalMid_Lock);
	receive_len = be32_to_cpu((__be32 )midQ->resp_buf);
	} else {
	cERROR(1,("No response buffer"));
	if(midQ->midState == MID_REQUEST_SUBMITTED) {
	if(ses->server->tcpStatus == CifsExiting)
	rc = -EHOSTDOWN;
	else {
	ses->server->tcpStatus = CifsNeedReconnect;
	midQ->midState = MID_RETRY_NEEDED;
	}
	}

	if (rc != -EHOSTDOWN) {
	if(midQ->midState == MID_RETRY_NEEDED) {
	rc = -EAGAIN;
	cFYI(1,("marking request for retry"));
	} else {
	rc = -EIO;
	}
	}
	spin_unlock(&GlobalMid_Lock);
	DeleteMidQEntry(midQ);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}
	return rc;
	}

	if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
	cERROR(1, ("Frame too large received. Length: %d Xid: %d",
	receive_len, xid));
	rc = -EIO;
	} else { /* rcvd frame is ok */

	if (midQ->resp_buf && out_buf
	&& (midQ->midState == MID_RESPONSE_RECEIVED)) {
	out_buf->smb_buf_length = receive_len;
	memcpy((char *)out_buf + 4,
	(char *)midQ->resp_buf + 4,
	receive_len);

	dump_smb(out_buf, 92);
	/* convert the length into a more usable form */
	if((receive_len > 24) &&
	(ses->server->secMode & (SECMODE_SIGN_REQUIRED \|
	SECMODE_SIGN_ENABLED))) {
	rc = cifs_verify_signature(out_buf,
	ses->server->mac_signing_key,
	midQ->sequence_number+1);
	if(rc) {
	cERROR(1,("Unexpected SMB signature"));
	/* BB FIXME add code to kill session */
	}
	}

	*pbytes_returned = out_buf->smb_buf_length;

	/* BB special case reconnect tid and uid here? */
	rc = map_smb_to_linux_error(out_buf);

	/* convert ByteCount if necessary */
	if (receive_len >=
	sizeof (struct smb_hdr) -
	4 /* do not count RFC1001 header */ +
	(2 * out_buf->WordCount) + 2 /* bcc */ )
	BCC(out_buf) = le16_to_cpu(BCC(out_buf));
	} else {
	rc = -EIO;
	cFYI(1,("Bad MID state? "));
	}
	}
	cifs_no_response_exit:
	DeleteMidQEntry(midQ);

	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}

	return rc;

	out_unlock:
	up(&ses->server->tcpSem);
	/* If not lock req, update # of requests on wire to server */
	if(long_op < 3) {
	atomic_dec(&ses->server->inFlight);
	wake_up(&ses->server->request_q);
	}

	return rc;
	}