airo: work around stack usage warning

gcc-11 with KASAN on 32-bit arm produces a warning about a function
that needs a lot of stack space:

drivers/net/wireless/cisco/airo.c: In function 'setup_card.constprop':
drivers/net/wireless/cisco/airo.c:3960:1: error: the frame size of 1512 bytes is larger than 1400 bytes [-Werror=frame-larger-than=]

Most of this is from a single large structure that could be dynamically
allocated or moved into the per-device structure.  However, as the callers
all seem to have a fairly well bounded call chain, the easiest change
is to pull out the part of the function that needs the large variables
into a separate function and mark that as noinline_for_stack. This does
not reduce the total stack usage, but it gets rid of the warning and
requires minimal changes otherwise.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210323131634.2669455-1-arnd@kernel.org

drivers/net/wireless/cisco/airo.c

@@ -3817,53 +3817,12 @@ static inline void set_auth_type(struct airo_info *local, int auth_type)
 		local->last_auth = auth_type;
 }
 
-static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
+static int noinline_for_stack airo_readconfig(struct airo_info *ai, u8 *mac, int lock)
 {
-	Cmd cmd;
-	Resp rsp;
-	int status;
-	SsidRid mySsid;
-	__le16 lastindex;
-	WepKeyRid wkr;
-	int rc;
-
-	memset(&mySsid, 0, sizeof(mySsid));
-	kfree (ai->flash);
-	ai->flash = NULL;
-
-	/* The NOP is the first step in getting the card going */
-	cmd.cmd = NOP;
-	cmd.parm0 = cmd.parm1 = cmd.parm2 = 0;
-	if (lock && down_interruptible(&ai->sem))
-		return ERROR;
-	if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
-		if (lock)
-			up(&ai->sem);
-		return ERROR;
-	}
-	disable_MAC(ai, 0);
-
-	// Let's figure out if we need to use the AUX port
-	if (!test_bit(FLAG_MPI,&ai->flags)) {
-		cmd.cmd = CMD_ENABLEAUX;
-		if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
-			if (lock)
-				up(&ai->sem);
-			airo_print_err(ai->dev->name, "Error checking for AUX port");
-			return ERROR;
-		}
-		if (!aux_bap || rsp.status & 0xff00) {
-			ai->bap_read = fast_bap_read;
-			airo_print_dbg(ai->dev->name, "Doing fast bap_reads");
-		} else {
-			ai->bap_read = aux_bap_read;
-			airo_print_dbg(ai->dev->name, "Doing AUX bap_reads");
-		}
-	}
-	if (lock)
-		up(&ai->sem);
-	if (ai->config.len == 0) {
-		int i;
+	int i, status;
+	/* large variables, so don't inline this function,
+	 * maybe change to kmalloc
+	 */
 	tdsRssiRid rssi_rid;
 	CapabilityRid cap_rid;
 
@@ -3876,7 +3835,7 @@ static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
 	status = readCapabilityRid(ai, &cap_rid, lock);
 	if (status != SUCCESS) return ERROR;
 
-		status = PC4500_readrid(ai, RID_RSSI,&rssi_rid, sizeof(rssi_rid), lock);
+	status = PC4500_readrid(ai, RID_RSSI, &rssi_rid, sizeof(rssi_rid), lock);
 	if (status == SUCCESS) {
 		if (ai->rssi || (ai->rssi = kmalloc(512, GFP_KERNEL)) != NULL)
 			memcpy(ai->rssi, (u8*)&rssi_rid + 2, 512); /* Skip RID length member */
@@ -3915,6 +3874,60 @@ static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
 		}
 	}
 	set_bit (FLAG_COMMIT, &ai->flags);
+
+	return SUCCESS;
+}
+
+
+static u16 setup_card(struct airo_info *ai, u8 *mac, int lock)
+{
+	Cmd cmd;
+	Resp rsp;
+	int status;
+	SsidRid mySsid;
+	__le16 lastindex;
+	WepKeyRid wkr;
+	int rc;
+
+	memset(&mySsid, 0, sizeof(mySsid));
+	kfree (ai->flash);
+	ai->flash = NULL;
+
+	/* The NOP is the first step in getting the card going */
+	cmd.cmd = NOP;
+	cmd.parm0 = cmd.parm1 = cmd.parm2 = 0;
+	if (lock && down_interruptible(&ai->sem))
+		return ERROR;
+	if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
+		if (lock)
+			up(&ai->sem);
+		return ERROR;
+	}
+	disable_MAC(ai, 0);
+
+	// Let's figure out if we need to use the AUX port
+	if (!test_bit(FLAG_MPI,&ai->flags)) {
+		cmd.cmd = CMD_ENABLEAUX;
+		if (issuecommand(ai, &cmd, &rsp, true) != SUCCESS) {
+			if (lock)
+				up(&ai->sem);
+			airo_print_err(ai->dev->name, "Error checking for AUX port");
+			return ERROR;
+		}
+		if (!aux_bap || rsp.status & 0xff00) {
+			ai->bap_read = fast_bap_read;
+			airo_print_dbg(ai->dev->name, "Doing fast bap_reads");
+		} else {
+			ai->bap_read = aux_bap_read;
+			airo_print_dbg(ai->dev->name, "Doing AUX bap_reads");
+		}
+	}
+	if (lock)
+		up(&ai->sem);
+	if (ai->config.len == 0) {
+		status = airo_readconfig(ai, mac, lock);
+		if (status != SUCCESS)
+			return ERROR;
 	}
 
 	/* Setup the SSIDs if present */