[PATCH v11 net-next 3/7] devlink: Change function syntax.

[Ratheesh Kannoth <rkannoth@marvell.com>]

union devlink_param_value grows when U64 array params
are added to devlink. This increase the size of union
devlink_param_value from 32 bytes to over 264 bytes.
devlink_nl_param_value_fill_one(), devlink_nl_param_value_put()
take multiple copies of this union by value. Passing two of
these unions by value consumes over 528 bytes of
stack space, and combined in a call chain this pushes nearly 800 bytes
of arguments onto the stack. There is higher chance of hitting
CONFIG_FRAME_WARN limits deep in deep functions. Change signatures
of the internal functions and exported APIs be updated to pass the
unions by pointer instead.

Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
---
 net/devlink/param.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/net/devlink/param.c b/net/devlink/param.c
index cf95268da5b0..4595fffbd825 100644
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -216,39 +216,39 @@ static int devlink_param_reset_default(struct devlink *devlink,
 
 static int
 devlink_nl_param_value_put(struct sk_buff *msg, enum devlink_param_type type,
-			   int nla_type, union devlink_param_value val,
+			   int nla_type, union devlink_param_value *val,
 			   bool flag_as_u8)
 {
 	switch (type) {
 	case DEVLINK_PARAM_TYPE_U8:
-		if (nla_put_u8(msg, nla_type, val.vu8))
+		if (nla_put_u8(msg, nla_type, val->vu8))
 			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_U16:
-		if (nla_put_u16(msg, nla_type, val.vu16))
+		if (nla_put_u16(msg, nla_type, val->vu16))
 			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_U32:
-		if (nla_put_u32(msg, nla_type, val.vu32))
+		if (nla_put_u32(msg, nla_type, val->vu32))
 			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_U64:
-		if (devlink_nl_put_u64(msg, nla_type, val.vu64))
+		if (devlink_nl_put_u64(msg, nla_type, val->vu64))
 			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_STRING:
-		if (nla_put_string(msg, nla_type, val.vstr))
+		if (nla_put_string(msg, nla_type, val->vstr))
 			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_BOOL:
-		/* default values of type bool are encoded with u8, so that
+		/* default val->es of type bool are encoded with u8, so that
 		 * false can be distinguished from not present
 		 */
 		if (flag_as_u8) {
-			if (nla_put_u8(msg, nla_type, val.vbool))
+			if (nla_put_u8(msg, nla_type, val->vbool))
 				return -EMSGSIZE;
 		} else {
-			if (val.vbool && nla_put_flag(msg, nla_type))
+			if (val->vbool && nla_put_flag(msg, nla_type))
 				return -EMSGSIZE;
 		}
 		break;
@@ -260,8 +260,8 @@ static int
 devlink_nl_param_value_fill_one(struct sk_buff *msg,
 				enum devlink_param_type type,
 				enum devlink_param_cmode cmode,
-				union devlink_param_value val,
-				union devlink_param_value default_val,
+				union devlink_param_value *val,
+				union devlink_param_value *default_val,
 				bool has_default)
 {
 	struct nlattr *param_value_attr;
@@ -383,8 +383,8 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 		if (!param_value_set[i])
 			continue;
 		err = devlink_nl_param_value_fill_one(msg, param->type,
-						      i, param_value[i],
-						      default_value[i],
+						      i, &param_value[i],
+						      &default_value[i],
 						      default_value_set[i]);
 		if (err)
 			goto values_list_nest_cancel;
-- 
2.43.0