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Subject[PATCH] tty: rocket: reduce stack usage
Date
The build of xtensa allmodconfig gives warning of:
In function 'get_ports.isra.0':
warning: the frame size of 1040 bytes is larger than 1024 bytes

Allocate memory for 'struct rocket_ports' dynamically to reduce the
stack usage, as an added benifit we can remove the memset by using
kzalloc while allocating memory.

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
drivers/tty/rocket.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index 5ba6816ebf81..cc1424b9a1e5 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -1222,22 +1222,25 @@ static int set_config(struct tty_struct *tty, struct r_port *info,
*/
static int get_ports(struct r_port *info, struct rocket_ports __user *retports)
{
- struct rocket_ports tmp;
- int board;
+ struct rocket_ports *tmp;
+ int board, ret = 0;

- memset(&tmp, 0, sizeof (tmp));
- tmp.tty_major = rocket_driver->major;
+ tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
+ tmp->tty_major = rocket_driver->major;

for (board = 0; board < 4; board++) {
- tmp.rocketModel[board].model = rocketModel[board].model;
- strcpy(tmp.rocketModel[board].modelString, rocketModel[board].modelString);
- tmp.rocketModel[board].numPorts = rocketModel[board].numPorts;
- tmp.rocketModel[board].loadrm2 = rocketModel[board].loadrm2;
- tmp.rocketModel[board].startingPortNumber = rocketModel[board].startingPortNumber;
- }
- if (copy_to_user(retports, &tmp, sizeof (*retports)))
- return -EFAULT;
- return 0;
+ tmp->rocketModel[board].model = rocketModel[board].model;
+ strcpy(tmp->rocketModel[board].modelString,
+ rocketModel[board].modelString);
+ tmp->rocketModel[board].numPorts = rocketModel[board].numPorts;
+ tmp->rocketModel[board].loadrm2 = rocketModel[board].loadrm2;
+ tmp->rocketModel[board].startingPortNumber =
+ rocketModel[board].startingPortNumber;
+ }
+ if (copy_to_user(retports, tmp, sizeof(*retports)))
+ ret = -EFAULT;
+ kfree(tmp);
+ return ret;
}

static int reset_rm2(struct r_port *info, void __user *arg)
--
2.11.0
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