[PATCH] serial_cs: Reduce stack usage in serial_event()

This patch reduces the stack usage of the function serial_event() in
serial_cs from 2212 to 228.  I used a patched version of gcc 3.4.3 on i386
with -fno-unit-at-a-time disabled.

This patch is only compile tested.

Acked-by: Randy Dunlap <rddunlap@osdl.org>
Signed-off-by: Yum Rayan <yum.rayan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 112 insertions, 61 deletions

diff --git a/drivers/serial/serial_cs.c b/drivers/serial/serial_cs.c
index 9034f9ad37c7..6eeb48f6a482 100644
--- a/drivers/serial/serial_cs.c
+++ b/drivers/serial/serial_cs.c
@@ -107,6 +107,13 @@ struct serial_info {
         int                     line[4];
 };
 
+struct serial_cfg_mem {
+        tuple_t tuple;
+        cisparse_t parse;
+        u_char buf[256];
+};
+
+
 static void serial_config(dev_link_t * link);
 static int serial_event(event_t event, int priority,
                         event_callback_args_t * args);
@@ -357,14 +364,24 @@ static int simple_config(dev_link_t *link)
         static int size_table[2] = { 8, 16 };
         client_handle_t handle = link->handle;
         struct serial_info *info = link->priv;
-        tuple_t tuple;
-        u_char buf[256];
-        cisparse_t parse;
-        cistpl_cftable_entry_t *cf = &parse.cftable_entry;
+        struct serial_cfg_mem *cfg_mem;
+        tuple_t *tuple;
+        u_char *buf;
+        cisparse_t *parse;
+        cistpl_cftable_entry_t *cf;
         config_info_t config;
         int i, j, try;
         int s;
 
+        cfg_mem = kmalloc(sizeof(struct serial_cfg_mem), GFP_KERNEL);
+        if (!cfg_mem)
+                return -1;
+
+        tuple = &cfg_mem->tuple;
+        parse = &cfg_mem->parse;
+        cf = &parse->cftable_entry;
+        buf = cfg_mem->buf;
+
         /* If the card is already configured, look up the port and irq */
         i = pcmcia_get_configuration_info(handle, &config);
         if ((i == CS_SUCCESS) && (config.Attributes & CONF_VALID_CLIENT)) {
@@ -377,21 +394,23 @@ static int simple_config(dev_link_t *link)
                         port = config.BasePort1 + 0x28;
                         info->slave = 1;
                 }
-                if (info->slave)
+                if (info->slave) {
+                        kfree(cfg_mem);
                         return setup_serial(handle, info, port, config.AssignedIRQ);
+                }
         }
         link->conf.Vcc = config.Vcc;
 
         /* First pass: look for a config entry that looks normal. */
-        tuple.TupleData = (cisdata_t *) buf;
-        tuple.TupleOffset = 0;
-        tuple.TupleDataMax = 255;
-        tuple.Attributes = 0;
-        tuple.DesiredTuple = CISTPL_CFTABLE_ENTRY;
+        tuple->TupleData = (cisdata_t *) buf;
+        tuple->TupleOffset = 0;
+        tuple->TupleDataMax = 255;
+        tuple->Attributes = 0;
+        tuple->DesiredTuple = CISTPL_CFTABLE_ENTRY;
         /* Two tries: without IO aliases, then with aliases */
         for (s = 0; s < 2; s++) {
                 for (try = 0; try < 2; try++) {
-                        i = first_tuple(handle, &tuple, &parse);
+                        i = first_tuple(handle, tuple, parse);
                         while (i != CS_NO_MORE_ITEMS) {
                                 if (i != CS_SUCCESS)
                                         goto next_entry;
@@ -409,14 +428,14 @@ static int simple_config(dev_link_t *link)
                                                 goto found_port;
                                 }
 next_entry:
-                                i = next_tuple(handle, &tuple, &parse);
+                                i = next_tuple(handle, tuple, parse);
                         }
                 }
         }
         /* Second pass: try to find an entry that isn't picky about
            its base address, then try to grab any standard serial port
            address, and finally try to get any free port. */
-        i = first_tuple(handle, &tuple, &parse);
+        i = first_tuple(handle, tuple, parse);
         while (i != CS_NO_MORE_ITEMS) {
                 if ((i == CS_SUCCESS) && (cf->io.nwin > 0) &&
                     ((cf->io.flags & CISTPL_IO_LINES_MASK) <= 3)) {
@@ -429,7 +448,7 @@ next_entry:
                                         goto found_port;
                         }
                 }
-                i = next_tuple(handle, &tuple, &parse);
+                i = next_tuple(handle, tuple, parse);
         }
 
       found_port:
@@ -437,6 +456,7 @@ next_entry:
                 printk(KERN_NOTICE
                        "serial_cs: no usable port range found, giving up\n");
                 cs_error(link->handle, RequestIO, i);
+                kfree(cfg_mem);
                 return -1;
         }
 
@@ -450,9 +470,10 @@ next_entry:
         i = pcmcia_request_configuration(link->handle, &link->conf);
         if (i != CS_SUCCESS) {
                 cs_error(link->handle, RequestConfiguration, i);
+                kfree(cfg_mem);
                 return -1;
         }
-
+        kfree(cfg_mem);
         return setup_serial(handle, info, link->io.BasePort1, link->irq.AssignedIRQ);
 }
 
@@ -460,29 +481,39 @@ static int multi_config(dev_link_t * link)
 {
         client_handle_t handle = link->handle;
         struct serial_info *info = link->priv;
-        tuple_t tuple;
-        u_char buf[256];
-        cisparse_t parse;
-        cistpl_cftable_entry_t *cf = &parse.cftable_entry;
+        struct serial_cfg_mem *cfg_mem;
+        tuple_t *tuple;
+        u_char *buf;
+        cisparse_t *parse;
+        cistpl_cftable_entry_t *cf;
         config_info_t config;
-        int i, base2 = 0;
+        int i, rc, base2 = 0;
+
+        cfg_mem = kmalloc(sizeof(struct serial_cfg_mem), GFP_KERNEL);
+        if (!cfg_mem)
+                return -1;
+        tuple = &cfg_mem->tuple;
+        parse = &cfg_mem->parse;
+        cf = &parse->cftable_entry;
+        buf = cfg_mem->buf;
 
         i = pcmcia_get_configuration_info(handle, &config);
         if (i != CS_SUCCESS) {
                 cs_error(handle, GetConfigurationInfo, i);
-                return -1;
+                rc = -1;
+                goto free_cfg_mem;
         }
         link->conf.Vcc = config.Vcc;
 
-        tuple.TupleData = (cisdata_t *) buf;
-        tuple.TupleOffset = 0;
-        tuple.TupleDataMax = 255;
-        tuple.Attributes = 0;
-        tuple.DesiredTuple = CISTPL_CFTABLE_ENTRY;
+        tuple->TupleData = (cisdata_t *) buf;
+        tuple->TupleOffset = 0;
+        tuple->TupleDataMax = 255;
+        tuple->Attributes = 0;
+        tuple->DesiredTuple = CISTPL_CFTABLE_ENTRY;
 
         /* First, look for a generic full-sized window */
         link->io.NumPorts1 = info->multi * 8;
-        i = first_tuple(handle, &tuple, &parse);
+        i = first_tuple(handle, tuple, parse);
         while (i != CS_NO_MORE_ITEMS) {
                 /* The quad port cards have bad CIS's, so just look for a
                    window larger than 8 ports and assume it will be right */
@@ -497,14 +528,14 @@ static int multi_config(dev_link_t * link)
                         if (i == CS_SUCCESS)
                                 break;
                 }
-                i = next_tuple(handle, &tuple, &parse);
+                i = next_tuple(handle, tuple, parse);
         }
 
         /* If that didn't work, look for two windows */
         if (i != CS_SUCCESS) {
                 link->io.NumPorts1 = link->io.NumPorts2 = 8;
                 info->multi = 2;
-                i = first_tuple(handle, &tuple, &parse);
+                i = first_tuple(handle, tuple, parse);
                 while (i != CS_NO_MORE_ITEMS) {
                         if ((i == CS_SUCCESS) && (cf->io.nwin == 2)) {
                                 link->conf.ConfigIndex = cf->index;
@@ -517,13 +548,14 @@ static int multi_config(dev_link_t * link)
                                 if (i == CS_SUCCESS)
                                         break;
                         }
-                        i = next_tuple(handle, &tuple, &parse);
+                        i = next_tuple(handle, tuple, parse);
                 }
         }
 
         if (i != CS_SUCCESS) {
                 cs_error(link->handle, RequestIO, i);
-                return -1;
+                rc = -1;
+                goto free_cfg_mem;
         }
 
         i = pcmcia_request_irq(link->handle, &link->irq);
@@ -541,7 +573,8 @@ static int multi_config(dev_link_t * link)
         i = pcmcia_request_configuration(link->handle, &link->conf);
         if (i != CS_SUCCESS) {
                 cs_error(link->handle, RequestConfiguration, i);
-                return -1;
+                rc = -1;
+                goto free_cfg_mem;
         }
 
         /* The Oxford Semiconductor OXCF950 cards are in fact single-port:
@@ -554,17 +587,23 @@ static int multi_config(dev_link_t * link)
                         setup_serial(handle, info, link->io.BasePort1, link->irq.AssignedIRQ);
                         outb(12, base2 + 1);
                 }
-                return 0;
+                rc = 0;
+                goto free_cfg_mem;
         }
 
         setup_serial(handle, info, link->io.BasePort1, link->irq.AssignedIRQ);
         /* The Nokia cards are not really multiport cards */
-        if (info->manfid == MANFID_NOKIA)
-                return 0;
+        if (info->manfid == MANFID_NOKIA) {
+                rc = 0;
+                goto free_cfg_mem;
+        }
         for (i = 0; i < info->multi - 1; i++)
-                setup_serial(handle, info, base2 + (8 * i), link->irq.AssignedIRQ);
-
-        return 0;
+                setup_serial(handle, info, base2 + (8 * i),
+                                link->irq.AssignedIRQ);
+        rc = 0;
+free_cfg_mem:
+        kfree(cfg_mem);
+        return rc;
 }
 
 /*======================================================================
@@ -579,39 +618,49 @@ void serial_config(dev_link_t * link)
 {
         client_handle_t handle = link->handle;
         struct serial_info *info = link->priv;
-        tuple_t tuple;
-        u_short buf[128];
-        cisparse_t parse;
-        cistpl_cftable_entry_t *cf = &parse.cftable_entry;
+        struct serial_cfg_mem *cfg_mem;
+        tuple_t *tuple;
+        u_char *buf;
+        cisparse_t *parse;
+        cistpl_cftable_entry_t *cf;
         int i, last_ret, last_fn;
 
         DEBUG(0, "serial_config(0x%p)\n", link);
 
-        tuple.TupleData = (cisdata_t *) buf;
-        tuple.TupleOffset = 0;
-        tuple.TupleDataMax = 255;
-        tuple.Attributes = 0;
+        cfg_mem = kmalloc(sizeof(struct serial_cfg_mem), GFP_KERNEL);
+        if (!cfg_mem)
+                goto failed;
+
+        tuple = &cfg_mem->tuple;
+        parse = &cfg_mem->parse;
+        cf = &parse->cftable_entry;
+        buf = cfg_mem->buf;
+
+        tuple->TupleData = (cisdata_t *) buf;
+        tuple->TupleOffset = 0;
+        tuple->TupleDataMax = 255;
+        tuple->Attributes = 0;
         /* Get configuration register information */
-        tuple.DesiredTuple = CISTPL_CONFIG;
-        last_ret = first_tuple(handle, &tuple, &parse);
+        tuple->DesiredTuple = CISTPL_CONFIG;
+        last_ret = first_tuple(handle, tuple, parse);
         if (last_ret != CS_SUCCESS) {
                 last_fn = ParseTuple;
                 goto cs_failed;
         }
-        link->conf.ConfigBase = parse.config.base;
-        link->conf.Present = parse.config.rmask[0];
+        link->conf.ConfigBase = parse->config.base;
+        link->conf.Present = parse->config.rmask[0];
 
         /* Configure card */
         link->state |= DEV_CONFIG;
 
         /* Is this a compliant multifunction card? */
-        tuple.DesiredTuple = CISTPL_LONGLINK_MFC;
-        tuple.Attributes = TUPLE_RETURN_COMMON | TUPLE_RETURN_LINK;
-        info->multi = (first_tuple(handle, &tuple, &parse) == CS_SUCCESS);
+        tuple->DesiredTuple = CISTPL_LONGLINK_MFC;
+        tuple->Attributes = TUPLE_RETURN_COMMON | TUPLE_RETURN_LINK;
+        info->multi = (first_tuple(handle, tuple, parse) == CS_SUCCESS);
 
         /* Is this a multiport card? */
-        tuple.DesiredTuple = CISTPL_MANFID;
-        if (first_tuple(handle, &tuple, &parse) == CS_SUCCESS) {
+        tuple->DesiredTuple = CISTPL_MANFID;
+        if (first_tuple(handle, tuple, parse) == CS_SUCCESS) {
                 info->manfid = le16_to_cpu(buf[0]);
                 for (i = 0; i < MULTI_COUNT; i++)
                         if ((info->manfid == multi_id[i].manfid) &&
@@ -623,13 +672,13 @@ void serial_config(dev_link_t * link)
 
         /* Another check for dual-serial cards: look for either serial or
            multifunction cards that ask for appropriate IO port ranges */
-        tuple.DesiredTuple = CISTPL_FUNCID;
+        tuple->DesiredTuple = CISTPL_FUNCID;
         if ((info->multi == 0) &&
-            ((first_tuple(handle, &tuple, &parse) != CS_SUCCESS) ||
-             (parse.funcid.func == CISTPL_FUNCID_MULTI) ||
-             (parse.funcid.func == CISTPL_FUNCID_SERIAL))) {
-                tuple.DesiredTuple = CISTPL_CFTABLE_ENTRY;
-                if (first_tuple(handle, &tuple, &parse) == CS_SUCCESS) {
+            ((first_tuple(handle, tuple, parse) != CS_SUCCESS) ||
+             (parse->funcid.func == CISTPL_FUNCID_MULTI) ||
+             (parse->funcid.func == CISTPL_FUNCID_SERIAL))) {
+                tuple->DesiredTuple = CISTPL_CFTABLE_ENTRY;
+                if (first_tuple(handle, tuple, parse) == CS_SUCCESS) {
                         if ((cf->io.nwin == 1) && (cf->io.win[0].len % 8 == 0))
                                 info->multi = cf->io.win[0].len >> 3;
                         if ((cf->io.nwin == 2) && (cf->io.win[0].len == 8) &&
@@ -664,6 +713,7 @@ void serial_config(dev_link_t * link)
 
         link->dev = &info->node[0];
         link->state &= ~DEV_CONFIG_PENDING;
+        kfree(cfg_mem);
         return;
 
  cs_failed:
@@ -671,6 +721,7 @@ void serial_config(dev_link_t * link)
  failed:
         serial_remove(link);
         link->state &= ~DEV_CONFIG_PENDING;
+        kfree(cfg_mem);
 }
 
 /*======================================================================