Re: Realtime Preemption, 2.6.12, Beginners Guide?

[Ingo Molnar <mingo@elte.hu>]

> (gdb) ####################################
> (gdb) # c02a0a26, stack size:  416 bytes #
> (gdb) ####################################
> (gdb) 0xc02a0a26 is in pcmcia_device_query (drivers/pcmcia/ds.c:436).

----
this patch reduces the stack footprint of pcmcia_device_query() from 416 
bytes to 36 bytes. (patch only build-tested)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Index: linux/drivers/pcmcia/ds.c
===================================================================
--- linux.orig/drivers/pcmcia/ds.c
+++ linux/drivers/pcmcia/ds.c
@@ -436,9 +436,13 @@ static int pcmcia_device_query(struct pc
 {
 	cistpl_manfid_t manf_id;
 	cistpl_funcid_t func_id;
-	cistpl_vers_1_t	vers1;
+	cistpl_vers_1_t	*vers1;
 	unsigned int i;
 
+	vers1 = kmalloc(sizeof(*vers1), GFP_KERNEL);
+	if (!vers1)
+		return -ENOMEM;
+
 	if (!pccard_read_tuple(p_dev->socket, p_dev->func,
 			       CISTPL_MANFID, &manf_id)) {
 		p_dev->manf_id = manf_id.manf;
@@ -455,23 +459,30 @@ static int pcmcia_device_query(struct pc
 		/* rule of thumb: cards with no FUNCID, but with
 		 * common memory device geometry information, are
 		 * probably memory cards (from pcmcia-cs) */
-		cistpl_device_geo_t devgeo;
+		cistpl_device_geo_t *devgeo;
+
+		devgeo = kmalloc(sizeof(*devgeo), GFP_KERNEL);
+		if (!devgeo) {
+			kfree(vers1);
+			return -ENOMEM;
+		}
 		if (!pccard_read_tuple(p_dev->socket, p_dev->func,
-				      CISTPL_DEVICE_GEO, &devgeo)) {
+				      CISTPL_DEVICE_GEO, devgeo)) {
 			ds_dbg(0, "mem device geometry probably means "
 			       "FUNCID_MEMORY\n");
 			p_dev->func_id = CISTPL_FUNCID_MEMORY;
 			p_dev->has_func_id = 1;
 		}
+		kfree(devgeo);
 	}
 
 	if (!pccard_read_tuple(p_dev->socket, p_dev->func, CISTPL_VERS_1,
-			       &vers1)) {
-		for (i=0; i < vers1.ns; i++) {
+			       vers1)) {
+		for (i=0; i < vers1->ns; i++) {
 			char *tmp;
 			unsigned int length;
 
-			tmp = vers1.str + vers1.ofs[i];
+			tmp = vers1->str + vers1->ofs[i];
 
 			length = strlen(tmp) + 1;
 			if ((length < 3) || (length > 255))
@@ -487,6 +498,7 @@ static int pcmcia_device_query(struct pc
 		}
 	}
 
+	kfree(vers1);
 	return 0;
 }
 
@@ -856,7 +868,9 @@ static int bind_request(struct pcmcia_bu
 rescan:
 	p_dev->cardmgr = p_drv;
 
-	pcmcia_device_query(p_dev);
+	ret = pcmcia_device_query(p_dev);
+	if (ret)
+		goto err_put_module;
 
 	/*
 	 * Prevent this racing with a card insertion.