added some optimisation for the case where the number of open files is

very large. files.c now promotes a files_struct to the top of the list
if it is used when it is more than 10 elements from the top.

also moved common linked list code for the 5 sets of linked lists that
I've created over the past few days into dlinklist.h (I've explained
to Chris why I didn't use the ubiqx code)
(This used to be commit 1eb9ae2996b5a243a147f485e7e353d54f820852)

7 files changed, 84 insertions, 95 deletions

diff --git a/source3/include/dlinklist.h b/source3/include/dlinklist.h
new file mode 100644
index 0000000000..8810eca5b9
--- /dev/null
+++ b/source3/include/dlinklist.h
@@ -0,0 +1,52 @@
+/* 
+   Unix SMB/Netbios implementation.
+   Version 1.9.
+   some simple double linked list macros
+   Copyright (C) Andrew Tridgell 1998
+   
+   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 the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/* To use these macros you must have a structure containing a next and
+   prev pointer */
+
+
+/* hook into the front of the list */
+#define DLIST_ADD(list, p) \
+        if (!(list)) { \
+		(list) = (p); \
+		(p)->next = (p)->prev = NULL; \
+	} else { \
+		(list)->prev = (p); \
+		(p)->next = (list); \
+		(p)->prev = NULL; \
+		(list) = (p); \
+	}
+
+
+/* remove an element from a list */
+#define DLIST_REMOVE(list, p) \
+	if ((p) == (list)) { \
+		(list) = (p)->next; \
+		if (list) (list)->prev = NULL; \
+	} else { \
+		(p)->prev->next = (p)->next; \
+		if ((p)->next) (p)->next->prev = (p)->prev; \
+	}
+
+/* promote an element to the top of the list */
+#define DLIST_PROMOTE(list, p) \
+          DLIST_REMOVE(list, p) \
+          DLIST_ADD(list, p)
diff --git a/source3/include/includes.h b/source3/include/includes.h
index 4ced157359..3fd5f7be08 100644
--- a/source3/include/includes.h
+++ b/source3/include/includes.h
@@ -314,6 +314,8 @@ extern int errno;
 /* Lists, trees, caching, datbase... */
 #include "ubi_sLinkList.h"
 #include "ubi_dLinkList.h"
+#include "dlinklist.h"
+
 #ifndef UBI_BINTREE_H
 #include "ubi_Cache.h"
 #endif /* UBI_BINTREE_H */
diff --git a/source3/lib/util_hnd.c b/source3/lib/util_hnd.c
index 2fc2c73ea3..d65116e646 100644
--- a/source3/lib/util_hnd.c
+++ b/source3/lib/util_hnd.c
@@ -124,14 +124,7 @@ BOOL open_lsa_policy_hnd(POLICY_HND *hnd)
 
 	bitmap_set(bmap, i);
 
-	/* hook into the front of the list */
-	if (!Policy) {
-		Policy = p;
-	} else {
-		Policy->prev = p;
-		p->next = Policy;
-		Policy = p;
-	}
+	DLIST_ADD(Policy, p);
 	
 	DEBUG(4,("Opened policy hnd[%x] ", i));
 	dump_data(4, (char *)hnd->data, sizeof(hnd->data));
@@ -303,13 +296,7 @@ BOOL close_lsa_policy_hnd(POLICY_HND *hnd)
 
 	DEBUG(3,("Closed policy name pnum=%x\n",  p->pnum));
 
-	if (p == Policy) {
-		Policy = p->next;
-		if (Policy) Policy->prev = NULL;
-	} else {
-		p->prev->next = p->next;
-		if (p->next) p->next->prev = p->prev;
-	}
+	DLIST_REMOVE(Policy, p);
 
 	bitmap_clear(bmap, p->pnum);
 
diff --git a/source3/rpc_server/srv_lsa_hnd.c b/source3/rpc_server/srv_lsa_hnd.c
index 2fc2c73ea3..d65116e646 100644
--- a/source3/rpc_server/srv_lsa_hnd.c
+++ b/source3/rpc_server/srv_lsa_hnd.c
@@ -124,14 +124,7 @@ BOOL open_lsa_policy_hnd(POLICY_HND *hnd)
 
 	bitmap_set(bmap, i);
 
-	/* hook into the front of the list */
-	if (!Policy) {
-		Policy = p;
-	} else {
-		Policy->prev = p;
-		p->next = Policy;
-		Policy = p;
-	}
+	DLIST_ADD(Policy, p);
 	
 	DEBUG(4,("Opened policy hnd[%x] ", i));
 	dump_data(4, (char *)hnd->data, sizeof(hnd->data));
@@ -303,13 +296,7 @@ BOOL close_lsa_policy_hnd(POLICY_HND *hnd)
 
 	DEBUG(3,("Closed policy name pnum=%x\n",  p->pnum));
 
-	if (p == Policy) {
-		Policy = p->next;
-		if (Policy) Policy->prev = NULL;
-	} else {
-		p->prev->next = p->next;
-		if (p->next) p->next->prev = p->prev;
-	}
+	DLIST_REMOVE(Policy, p);
 
 	bitmap_clear(bmap, p->pnum);
 
diff --git a/source3/rpc_server/srv_pipe_hnd.c b/source3/rpc_server/srv_pipe_hnd.c
index 368bf013a0..b030ee0e90 100644
--- a/source3/rpc_server/srv_pipe_hnd.c
+++ b/source3/rpc_server/srv_pipe_hnd.c
@@ -91,14 +91,7 @@ pipes_struct *open_rpc_pipe_p(char *pipe_name,
 	p = (pipes_struct *)malloc(sizeof(*p));
 	if (!p) return NULL;
 
-	/* hook into the front of the list */
-	if (!Pipes) {
-		Pipes = p;
-	} else {
-		Pipes->prev = p;
-		p->next = Pipes;
-		Pipes = p;
-	}
+	DLIST_ADD(Pipes, p);
 
 	bitmap_set(bmap, i);
 	i += PIPE_HANDLE_OFFSET;
@@ -292,13 +285,7 @@ BOOL close_rpc_pipe_hnd(pipes_struct *p, connection_struct *conn)
 	DEBUG(4,("closed pipe name %s pnum=%x (pipes_open=%d)\n", 
 		 p->name, p->pnum, pipes_open));  
 
-	if (p == Pipes) {
-		Pipes = p->next;
-		if (Pipes) Pipes->prev = NULL;
-	} else {
-		p->prev->next = p->next;
-		if (p->next) p->next->prev = p->prev;
-	}
+	DLIST_REMOVE(Pipes, p);
 
 	memset(p, 0, sizeof(*p));
 
diff --git a/source3/smbd/conn.c b/source3/smbd/conn.c
index b110e8d082..2afbfb7d7e 100644
--- a/source3/smbd/conn.c
+++ b/source3/smbd/conn.c
@@ -72,10 +72,16 @@ find a conn given a cnum
 ****************************************************************************/
 connection_struct *conn_find(int cnum)
 {
+	int count=0;
 	connection_struct *conn;
 
-	for (conn=Connections;conn;conn=conn->next) {
-		if (conn->cnum == cnum) return conn;
+	for (conn=Connections;conn;conn=conn->next,count++) {
+		if (conn->cnum == cnum) {
+			if (count > 10) {
+				DLIST_PROMOTE(Connections, conn);
+			}
+			return conn;
+		}
 	}
 
 	return NULL;
@@ -114,14 +120,7 @@ connection_struct *conn_new(void)
 	string_init(&conn->connectpath,"");
 	string_init(&conn->origpath,"");
 	
-	/* hook into the front of the list */
-	if (!Connections) {
-		Connections = conn;
-	} else {
-		Connections->prev = conn;
-		conn->next = Connections;
-		Connections = conn;
-	}
+	DLIST_ADD(Connections, conn);
 
 	return conn;
 }
@@ -165,13 +164,7 @@ free a conn structure
 ****************************************************************************/
 void conn_free(connection_struct *conn)
 {
-	if (conn == Connections) {
-		Connections = conn->next;
-		if (Connections) Connections->prev = NULL;
-	} else {
-		conn->prev->next = conn->next;
-		if (conn->next) conn->next->prev = conn->prev;
-	}
+	DLIST_REMOVE(Connections, conn);
 
 	if (conn->ngroups && conn->groups) {
 		free(conn->groups);
diff --git a/source3/smbd/files.c b/source3/smbd/files.c
index 7bd5501de5..fa1b8f3bac 100644
--- a/source3/smbd/files.c
+++ b/source3/smbd/files.c
@@ -100,14 +100,7 @@ files_struct *file_new(void )
 	fsp->fnum = i + FILE_HANDLE_OFFSET;
 	string_init(&fsp->fsp_name,"");
 	
-	/* hook into the front of the list */
-	if (!Files) {
-		Files = fsp;
-	} else {
-		Files->prev = fsp;
-		fsp->next = Files;
-		Files = fsp;
-	}
+	DLIST_ADD(Files, fsp);
 
 	DEBUG(5,("allocated file structure %d (%d used)\n",
 		 i, files_used));
@@ -180,14 +173,7 @@ file_fd_struct *fd_get_new(void)
 	bitmap_set(fd_bmap, i);
 	fd_ptr_used++;
 
-	/* hook into the front of the list */
-	if (!FileFd) {
-		FileFd = fd_ptr;
-	} else {
-		FileFd->prev = fd_ptr;
-		fd_ptr->next = FileFd;
-		FileFd = fd_ptr;
-	}
+	DLIST_ADD(FileFd, fd_ptr);
 
 	DEBUG(5,("allocated fd_ptr structure %d (%d used)\n",
 		 i, fd_ptr_used));
@@ -269,14 +255,18 @@ find a fsp given a device, inode and timevalue
 ****************************************************************************/
 files_struct *file_find_dit(int dev, int inode, struct timeval *tval)
 {
+	int count=0;
 	files_struct *fsp;
 
-	for (fsp=Files;fsp;fsp=fsp->next) {
+	for (fsp=Files;fsp;fsp=fsp->next,count++) {
 		if (fsp->open && 
 		    fsp->fd_ptr->dev == dev && 
 		    fsp->fd_ptr->inode == inode &&
 		    fsp->open_time.tv_sec == tval->tv_sec &&
 		    fsp->open_time.tv_usec == tval->tv_usec) {
+			if (count > 10) {
+				DLIST_PROMOTE(Files, fsp);
+			}
 			return fsp;
 		}
 	}
@@ -320,13 +310,7 @@ free up a fd_ptr
 ****************************************************************************/
 static void fd_ptr_free(file_fd_struct *fd_ptr)
 {
-	if (fd_ptr == FileFd) {
-		FileFd = fd_ptr->next;
-		if (FileFd) FileFd->prev = NULL;
-	} else {
-		fd_ptr->prev->next = fd_ptr->next;
-		if (fd_ptr->next) fd_ptr->next->prev = fd_ptr->prev;
-	}
+	DLIST_REMOVE(FileFd, fd_ptr);
 
 	bitmap_clear(fd_bmap, fd_ptr->fdnum);
 	fd_ptr_used--;
@@ -346,13 +330,7 @@ free up a fsp
 ****************************************************************************/
 void file_free(files_struct *fsp)
 {
-	if (fsp == Files) {
-		Files = fsp->next;
-		if (Files) Files->prev = NULL;
-	} else {
-		fsp->prev->next = fsp->next;
-		if (fsp->next) fsp->next->prev = fsp->prev;
-	}
+	DLIST_REMOVE(Files, fsp);
 
 	string_free(&fsp->fsp_name);
 
@@ -381,16 +359,19 @@ get a fsp from a packet given the offset of a 16 bit fnum
 ****************************************************************************/
 files_struct *file_fsp(char *buf, int where)
 {
-	int fnum;
+	int fnum, count=0;
 	files_struct *fsp;
 
 	if (chain_fsp) return chain_fsp;
 
 	fnum = SVAL(buf, where);
 
-	for (fsp=Files;fsp;fsp=fsp->next) {
+	for (fsp=Files;fsp;fsp=fsp->next, count++) {
 		if (fsp->fnum == fnum) {
 			chain_fsp = fsp;
+			if (count > 10) {
+				DLIST_PROMOTE(Files, fsp);
+			}
 			return fsp;
 		}
 	}