[SSI] openssi/kernel/cluster/ssi/vproc procfs_subr.c,1.18,1.19

Update of /cvsroot/ssic-linux/openssi/kernel/cluster/ssi/vproc
In directory sfp-cvsdas-3.v30.ch3.sourceforge.com:/tmp/cvs-serv3482/cluster/ssi/vproc

Modified Files:
      Tag: OPENSSI-FC
	procfs_subr.c 
Log Message:
Reduce stack usage in ssi_get_tgid_list().


Index: procfs_subr.c
===================================================================
RCS file: /cvsroot/ssic-linux/openssi/kernel/cluster/ssi/vproc/procfs_subr.c,v
retrieving revision 1.18
retrieving revision 1.19
diff -u -d -r1.18 -r1.19
--- procfs_subr.c	25 Oct 2010 04:34:58 -0000	1.18
+++ procfs_subr.c	25 Oct 2010 05:08:56 -0000	1.19
@@ -18,11 +18,11 @@
 #endif
 
 struct proc_root_readdir_cookie {
+	unsigned int start_index;
 	unsigned int cur_index;
 	clusternode_t start_node;
 	int h_index;
 	int v_index;
-	unsigned int start_index;
 	unsigned int pid_list[PROC_MAXPIDS];
 };
 
@@ -43,11 +43,11 @@
 	if (cp == NULL)
 		return -ENOMEM;
 #ifdef PROC_LARGE_MAXPIDS
+	cp->start_index = 0;
 	cp->cur_index = 0;
 	cp->start_node = 0;
 	cp->h_index = 0;
 	cp->v_index = 0;
-	cp->start_index = 0;
 #endif
 	file->private_data = cp;
 	return 0;
@@ -66,49 +66,48 @@
 int
 ssi_get_tgid_list(struct file *file, unsigned int index, unsigned int *pids)
 {
-	int nr_pids = 0;
 	struct proc_root_readdir_cookie *cp = file->private_data;
-	clusternode_t start_node;
-	int h_index = 0;
-	int v_index = 0;
-	int error = 0;
 	nsc_nodelist_t *nodelist;
 	nsc_nlcookie_t cookie;
 	clusternode_t node;
-	int pids_size;
-	int pids_off;
-	unsigned int out_index;
-	unsigned int start_index;
 	u_int *pidsp;
+	int pids_size, nr_pids = 0;
+	unsigned int out_index;
+	int pids_off;
 
-	start_node = 0;
-	out_index = 1;
-	start_index = index;
-	if (cp->start_index != 0 && index >= cp->start_index) {
+	if (cp->start_index && index >= cp->start_index) {
 		/* Use the saved starting position. */
-		start_node = cp->start_node;
-		h_index = cp->h_index;
-		v_index = cp->v_index;
 		out_index = cp->cur_index;
-		if (index < cp->cur_index) {
+		/* If caller truncated read, fill-in pids from previous read */
+		if (unlikely(index < cp->cur_index)) {
 			nr_pids = cp->cur_index - index;
+			BUG_ON(nr_pids > PROC_MAXPIDS);
 			memcpy(pids, cp->pid_list + index - cp->start_index,
 			       nr_pids * sizeof(unsigned int));
 			index = cp->cur_index;
 		}
+		BUG_ON(index > cp->cur_index);
+	} else {
+		/* Reset the saved starting position. */
+		cp->start_node = 0;
+		cp->h_index = 0;
+		cp->v_index = 0;
+		out_index = 1;
 	}
+
 	/* get node list */
 	nodelist = clms_get_nsc_nodelist(CLMS_NODE_UP
 					 |CLMS_NODE_HALF_UP
 					 |CLMS_NODE_HALF_DOWN);
-
 	NSC_NLCOOKIE_INIT(&cookie);
 	if (NSC_NODELIST_TEST1(nodelist, this_node)) {
 		node = NSC_NODELIST_GET_NEXT(&cookie,nodelist);
-		while ((start_node != 0) && (node != start_node)) {
-			node = NSC_NODELIST_GET_NEXT(&cookie,nodelist);
-			if (node == CLUSTERNODE_INVAL)
-				goto out;
+		if (cp->start_node) {
+			while (node != cp->start_node) {
+				node = NSC_NODELIST_GET_NEXT(&cookie,nodelist);
+				if (node == CLUSTERNODE_INVAL)
+					goto out;
+			}
 		}
 	}
 	else {
@@ -123,10 +122,10 @@
 	for (;;) {
 		pids_size = PROC_MAXPIDS - nr_pids;
 		pidsp = pids + nr_pids;
-		error = PVPSOP_GET_TGID_LIST(node, &pidsp,
-					    &pids_size, &h_index, &v_index);
-		if (error)
+		if (PVPSOP_GET_TGID_LIST(node, &pidsp,
+				&pids_size, &cp->h_index, &cp->v_index)) {
 			pids_size = 0;
+		}
 		if (out_index != index) {
 			pids_off = index - out_index;
 			out_index += pids_size;
@@ -144,23 +143,20 @@
 			}
 		}
 		nr_pids += pids_size;
-		if (nr_pids < PROC_MAXPIDS) {
-			node = NSC_NODELIST_GET_NEXT(&cookie, nodelist);
-			if (node == CLUSTERNODE_INVAL)
-				break;
-		} else
+		if (nr_pids >= PROC_MAXPIDS)
+			break;
+		node = NSC_NODELIST_GET_NEXT(&cookie, nodelist);
+		if (node == CLUSTERNODE_INVAL)
 			break;
 		/* reset index values */
-		h_index = 0;
-		v_index = 0;
+		cp->h_index = 0;
+		cp->v_index = 0;
 	}
 out:
 	NSC_NODELIST_FREE(nodelist);
-	cp->start_index = start_index;
-	cp->cur_index = start_index + nr_pids;
+	cp->start_index = index;
+	cp->cur_index = index + nr_pids;
 	cp->start_node = node;
-	cp->h_index = h_index;
-	cp->v_index = v_index;
 	memcpy(cp->pid_list, pids, nr_pids * sizeof(unsigned int));
 
 	return nr_pids;


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