Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French.

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  CIFS: Move get_next_mid to ops struct
  CIFS: Make accessing is_valid_oplock/dump_detail ops struct field safe
  CIFS: Improve identation in cifs_unlock_range
  CIFS: Fix possible wrong memory allocation

Author: torvalds

fs/cifs/cifsglob.h

@@ -174,6 +174,7 @@ struct smb_version_operations {
 	void (*add_credits)(struct TCP_Server_Info *, const unsigned int);
 	void (*set_credits)(struct TCP_Server_Info *, const int);
 	int * (*get_credits_field)(struct TCP_Server_Info *);
+	__u64 (*get_next_mid)(struct TCP_Server_Info *);
 	/* data offset from read response message */
 	unsigned int (*read_data_offset)(char *);
 	/* data length from read response message */
@@ -399,6 +400,12 @@ set_credits(struct TCP_Server_Info *server, const int val)
 	server->ops->set_credits(server, val);
 }
 
+static inline __u64
+get_next_mid(struct TCP_Server_Info *server)
+{
+	return server->ops->get_next_mid(server);
+}
+
 /*
  * Macros to allow the TCP_Server_Info->net field and related code to drop out
  * when CONFIG_NET_NS isn't set.

fs/cifs/cifsproto.h

@@ -114,7 +114,6 @@ extern int small_smb_init_no_tc(const int smb_cmd, const int wct,
 				void **request_buf);
 extern int CIFS_SessSetup(unsigned int xid, struct cifs_ses *ses,
 			     const struct nls_table *nls_cp);
-extern __u64 GetNextMid(struct TCP_Server_Info *server);
 extern struct timespec cifs_NTtimeToUnix(__le64 utc_nanoseconds_since_1601);
 extern u64 cifs_UnixTimeToNT(struct timespec);
 extern struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time,

fs/cifs/cifssmb.c

@@ -268,7 +268,7 @@ small_smb_init_no_tc(const int smb_command, const int wct,
 		return rc;
 
 	buffer = (struct smb_hdr *)*request_buf;
-	buffer->Mid = GetNextMid(ses->server);
+	buffer->Mid = get_next_mid(ses->server);
 	if (ses->capabilities & CAP_UNICODE)
 		buffer->Flags2 |= SMBFLG2_UNICODE;
 	if (ses->capabilities & CAP_STATUS32)
@@ -402,7 +402,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifs_ses *ses)
 
 	cFYI(1, "secFlags 0x%x", secFlags);
 
-	pSMB->hdr.Mid = GetNextMid(server);
+	pSMB->hdr.Mid = get_next_mid(server);
 	pSMB->hdr.Flags2 |= (SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS);
 
 	if ((secFlags & CIFSSEC_MUST_KRB5) == CIFSSEC_MUST_KRB5)
@@ -782,7 +782,7 @@ CIFSSMBLogoff(const int xid, struct cifs_ses *ses)
 		return rc;
 	}
 
-	pSMB->hdr.Mid = GetNextMid(ses->server);
+	pSMB->hdr.Mid = get_next_mid(ses->server);
 
 	if (ses->server->sec_mode &
 		   (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
@@ -4762,7 +4762,7 @@ CIFSGetDFSRefer(const int xid, struct cifs_ses *ses,
 
 	/* server pointer checked in called function,
 	but should never be null here anyway */
-	pSMB->hdr.Mid = GetNextMid(ses->server);
+	pSMB->hdr.Mid = get_next_mid(ses->server);
 	pSMB->hdr.Tid = ses->ipc_tid;
 	pSMB->hdr.Uid = ses->Suid;
 	if (ses->capabilities & CAP_STATUS32)

fs/cifs/connect.c

@@ -1058,13 +1058,15 @@ cifs_demultiplex_thread(void *p)
 		if (mid_entry != NULL) {
 			if (!mid_entry->multiRsp || mid_entry->multiEnd)
 				mid_entry->callback(mid_entry);
-		} else if (!server->ops->is_oplock_break(buf, server)) {
+		} else if (!server->ops->is_oplock_break ||
+			   !server->ops->is_oplock_break(buf, server)) {
 			cERROR(1, "No task to wake, unknown frame received! "
 				   "NumMids %d", atomic_read(&midCount));
 			cifs_dump_mem("Received Data is: ", buf,
 				      HEADER_SIZE(server));
 #ifdef CONFIG_CIFS_DEBUG2
-			server->ops->dump_detail(buf);
+			if (server->ops->dump_detail)
+				server->ops->dump_detail(buf);
 			cifs_dump_mids(server);
 #endif /* CIFS_DEBUG2 */
 
@@ -3938,7 +3940,7 @@ CIFSTCon(unsigned int xid, struct cifs_ses *ses,
 	header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
 			NULL /*no tid */ , 4 /*wct */ );
 
-	smb_buffer->Mid = GetNextMid(ses->server);
+	smb_buffer->Mid = get_next_mid(ses->server);
 	smb_buffer->Uid = ses->Suid;
 	pSMB = (TCONX_REQ *) smb_buffer;
 	pSMBr = (TCONX_RSP *) smb_buffer_response;

fs/cifs/file.c

@@ -876,7 +876,7 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
 	struct cifsLockInfo *li, *tmp;
 	struct cifs_tcon *tcon;
 	struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
-	unsigned int num, max_num;
+	unsigned int num, max_num, max_buf;
 	LOCKING_ANDX_RANGE *buf, *cur;
 	int types[] = {LOCKING_ANDX_LARGE_FILES,
 		       LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES};
@@ -892,8 +892,19 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
 		return rc;
 	}
 
-	max_num = (tcon->ses->server->maxBuf - sizeof(struct smb_hdr)) /
-		  sizeof(LOCKING_ANDX_RANGE);
+	/*
+	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
+	 * and check it for zero before using.
+	 */
+	max_buf = tcon->ses->server->maxBuf;
+	if (!max_buf) {
+		mutex_unlock(&cinode->lock_mutex);
+		FreeXid(xid);
+		return -EINVAL;
+	}
+
+	max_num = (max_buf - sizeof(struct smb_hdr)) /
+						sizeof(LOCKING_ANDX_RANGE);
 	buf = kzalloc(max_num * sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
 	if (!buf) {
 		mutex_unlock(&cinode->lock_mutex);
@@ -1218,7 +1229,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
 	int types[] = {LOCKING_ANDX_LARGE_FILES,
 		       LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES};
 	unsigned int i;
-	unsigned int max_num, num;
+	unsigned int max_num, num, max_buf;
 	LOCKING_ANDX_RANGE *buf, *cur;
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
@@ -1228,8 +1239,16 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
 
 	INIT_LIST_HEAD(&tmp_llist);
 
-	max_num = (tcon->ses->server->maxBuf - sizeof(struct smb_hdr)) /
-		  sizeof(LOCKING_ANDX_RANGE);
+	/*
+	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
+	 * and check it for zero before using.
+	 */
+	max_buf = tcon->ses->server->maxBuf;
+	if (!max_buf)
+		return -EINVAL;
+
+	max_num = (max_buf - sizeof(struct smb_hdr)) /
+						sizeof(LOCKING_ANDX_RANGE);
 	buf = kzalloc(max_num * sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -1247,54 +1266,49 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, int xid)
 				continue;
 			if (types[i] != li->type)
 				continue;
-			if (!cinode->can_cache_brlcks) {
-				cur->Pid = cpu_to_le16(li->pid);
-				cur->LengthLow = cpu_to_le32((u32)li->length);
-				cur->LengthHigh =
-					cpu_to_le32((u32)(li->length>>32));
-				cur->OffsetLow = cpu_to_le32((u32)li->offset);
-				cur->OffsetHigh =
-					cpu_to_le32((u32)(li->offset>>32));
-				/*
-				 * We need to save a lock here to let us add
-				 * it again to the file's list if the unlock
-				 * range request fails on the server.
-				 */
-				list_move(&li->llist, &tmp_llist);
-				if (++num == max_num) {
-					stored_rc = cifs_lockv(xid, tcon,
-							       cfile->netfid,
-							       li->type, num,
-							       0, buf);
-					if (stored_rc) {
-						/*
-						 * We failed on the unlock range
-						 * request - add all locks from
-						 * the tmp list to the head of
-						 * the file's list.
-						 */
-						cifs_move_llist(&tmp_llist,
-								&cfile->llist);
-						rc = stored_rc;
-					} else
-						/*
-						 * The unlock range request
-						 * succeed - free the tmp list.
-						 */
-						cifs_free_llist(&tmp_llist);
-					cur = buf;
-					num = 0;
-				} else
-					cur++;
-			} else {
+			if (cinode->can_cache_brlcks) {
 				/*
 				 * We can cache brlock requests - simply remove
 				 * a lock from the file's list.
 				 */
 				list_del(&li->llist);
 				cifs_del_lock_waiters(li);
 				kfree(li);
+				continue;
 			}
+			cur->Pid = cpu_to_le16(li->pid);
+			cur->LengthLow = cpu_to_le32((u32)li->length);
+			cur->LengthHigh = cpu_to_le32((u32)(li->length>>32));
+			cur->OffsetLow = cpu_to_le32((u32)li->offset);
+			cur->OffsetHigh = cpu_to_le32((u32)(li->offset>>32));
+			/*
+			 * We need to save a lock here to let us add it again to
+			 * the file's list if the unlock range request fails on
+			 * the server.
+			 */
+			list_move(&li->llist, &tmp_llist);
+			if (++num == max_num) {
+				stored_rc = cifs_lockv(xid, tcon, cfile->netfid,
+						       li->type, num, 0, buf);
+				if (stored_rc) {
+					/*
+					 * We failed on the unlock range
+					 * request - add all locks from the tmp
+					 * list to the head of the file's list.
+					 */
+					cifs_move_llist(&tmp_llist,
+							&cfile->llist);
+					rc = stored_rc;
+				} else
+					/*
+					 * The unlock range request succeed -
+					 * free the tmp list.
+					 */
+					cifs_free_llist(&tmp_llist);
+				cur = buf;
+				num = 0;
+			} else
+				cur++;
 		}
 		if (num) {
 			stored_rc = cifs_lockv(xid, tcon, cfile->netfid,

fs/cifs/misc.c

@@ -212,93 +212,6 @@ cifs_small_buf_release(void *buf_to_free)
 	return;
 }
 
-/*
- * Find a free multiplex id (SMB mid). Otherwise there could be
- * mid collisions which might cause problems, demultiplexing the
- * wrong response to this request. Multiplex ids could collide if
- * one of a series requests takes much longer than the others, or
- * if a very large number of long lived requests (byte range
- * locks or FindNotify requests) are pending. No more than
- * 64K-1 requests can be outstanding at one time. If no
- * mids are available, return zero. A future optimization
- * could make the combination of mids and uid the key we use
- * to demultiplex on (rather than mid alone).
- * In addition to the above check, the cifs demultiplex
- * code already used the command code as a secondary
- * check of the frame and if signing is negotiated the
- * response would be discarded if the mid were the same
- * but the signature was wrong. Since the mid is not put in the
- * pending queue until later (when it is about to be dispatched)
- * we do have to limit the number of outstanding requests
- * to somewhat less than 64K-1 although it is hard to imagine
- * so many threads being in the vfs at one time.
- */
-__u64 GetNextMid(struct TCP_Server_Info *server)
-{
-	__u64 mid = 0;
-	__u16 last_mid, cur_mid;
-	bool collision;
-
-	spin_lock(&GlobalMid_Lock);
-
-	/* mid is 16 bit only for CIFS/SMB */
-	cur_mid = (__u16)((server->CurrentMid) & 0xffff);
-	/* we do not want to loop forever */
-	last_mid = cur_mid;
-	cur_mid++;
-
-	/*
-	 * This nested loop looks more expensive than it is.
-	 * In practice the list of pending requests is short,
-	 * fewer than 50, and the mids are likely to be unique
-	 * on the first pass through the loop unless some request
-	 * takes longer than the 64 thousand requests before it
-	 * (and it would also have to have been a request that
-	 * did not time out).
-	 */
-	while (cur_mid != last_mid) {
-		struct mid_q_entry *mid_entry;
-		unsigned int num_mids;
-
-		collision = false;
-		if (cur_mid == 0)
-			cur_mid++;
-
-		num_mids = 0;
-		list_for_each_entry(mid_entry, &server->pending_mid_q, qhead) {
-			++num_mids;
-			if (mid_entry->mid == cur_mid &&
-			    mid_entry->mid_state == MID_REQUEST_SUBMITTED) {
-				/* This mid is in use, try a different one */
-				collision = true;
-				break;
-			}
-		}
-
-		/*
-		 * if we have more than 32k mids in the list, then something
-		 * is very wrong. Possibly a local user is trying to DoS the
-		 * box by issuing long-running calls and SIGKILL'ing them. If
-		 * we get to 2^16 mids then we're in big trouble as this
-		 * function could loop forever.
-		 *
-		 * Go ahead and assign out the mid in this situation, but force
-		 * an eventual reconnect to clean out the pending_mid_q.
-		 */
-		if (num_mids > 32768)
-			server->tcpStatus = CifsNeedReconnect;
-
-		if (!collision) {
-			mid = (__u64)cur_mid;
-			server->CurrentMid = mid;
-			break;
-		}
-		cur_mid++;
-	}
-	spin_unlock(&GlobalMid_Lock);
-	return mid;
-}
-
 /* NB: MID can not be set if treeCon not passed in, in that
    case it is responsbility of caller to set the mid */
 void
@@ -334,7 +247,7 @@ header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 
 			/* Uid is not converted */
 			buffer->Uid = treeCon->ses->Suid;
-			buffer->Mid = GetNextMid(treeCon->ses->server);
+			buffer->Mid = get_next_mid(treeCon->ses->server);
 		}
 		if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 			buffer->Flags2 |= SMBFLG2_DFS;