[PATCH V3] staging: dgap: implement error handling in dgap_tty_register()

Daeseok Youn
2014-05-19T02:11:11Z

- alloc_tty_driver() is deprecated so it is changed to
tty_alloc_driver()
- Pointers which are allocated by alloc_tty_driver() and kzalloc()
can be NULL so it need to check NULL for them.
- If one of those is failed, it need to add proper handler for
avoiding memory leak.
- If both of drivers are registered normally, and
then set TRUE to dgap_major_serial{print}_registered. If one
of drivers is failed to register, leave a default value as
FALSE.

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
---
V2: rebased on staging-next branch
V3: removes unneeded information in e-mail

drivers/staging/dgap/dgap.c | 49 +++++++++++++++++++++++++++++++++---------
1 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/dgap/dgap.c b/drivers/staging/dgap/dgap.c
index d7cfc45..e4cb7aa 100644
--- a/drivers/staging/dgap/dgap.c
+++ b/drivers/staging/dgap/dgap.c
@@ -1212,7 +1212,9 @@ static int dgap_tty_register(struct board_t *brd)
{
int rc = 0;

- brd->serial_driver = alloc_tty_driver(MAXPORTS);
+ brd->serial_driver = tty_alloc_driver(MAXPORTS, 0);
+ if (IS_ERR(brd->serial_driver))
+ return PTR_ERR(brd->serial_driver);

snprintf(brd->serial_name, MAXTTYNAMELEN, "tty_dgap_%d_",
brd->boardnum);
@@ -1231,8 +1233,10 @@ static int dgap_tty_register(struct board_t *brd)
/* The kernel wants space to store pointers to tty_structs */
brd->serial_driver->ttys =
kzalloc(MAXPORTS * sizeof(struct tty_struct *), GFP_KERNEL);
- if (!brd->serial_driver->ttys)
- return -ENOMEM;
+ if (!brd->serial_driver->ttys) {
+ rc = -ENOMEM;
+ goto free_serial_drv;
+ }

/*
* Entry points for driver. Called by the kernel from
@@ -1245,7 +1249,11 @@ static int dgap_tty_register(struct board_t *brd)
* again, separately so we don't get the LD confused about what major
* we are when we get into the dgap_tty_open() routine.
*/
- brd->print_driver = alloc_tty_driver(MAXPORTS);
+ brd->print_driver = tty_alloc_driver(MAXPORTS, 0);
+ if (IS_ERR(brd->print_driver)) {
+ rc = PTR_ERR(brd->print_driver);
+ goto free_serial_ttys;
+ }

snprintf(brd->print_name, MAXTTYNAMELEN, "pr_dgap_%d_",
brd->boardnum);
@@ -1264,8 +1272,10 @@ static int dgap_tty_register(struct board_t *brd)
/* The kernel wants space to store pointers to tty_structs */
brd->print_driver->ttys =
kzalloc(MAXPORTS * sizeof(struct tty_struct *), GFP_KERNEL);
- if (!brd->print_driver->ttys)
- return -ENOMEM;
+ if (!brd->print_driver->ttys) {
+ rc = -ENOMEM;
+ goto free_print_drv;
+ }

/*
* Entry points for driver. Called by the kernel from
@@ -1276,20 +1286,37 @@ static int dgap_tty_register(struct board_t *brd)
/* Register tty devices */
rc = tty_register_driver(brd->serial_driver);
if (rc < 0)
- return rc;
- brd->dgap_major_serial_registered = TRUE;
- dgap_boards_by_major[brd->serial_driver->major] = brd;
- brd->dgap_serial_major = brd->serial_driver->major;
+ goto free_print_ttys;

/* Register Transparent Print devices */
rc = tty_register_driver(brd->print_driver);
if (rc < 0)
- return rc;
+ goto unregister_serial_drv;
+
+ brd->dgap_major_serial_registered = TRUE;
+ dgap_boards_by_major[brd->serial_driver->major] = brd;
+ brd->dgap_serial_major = brd->serial_driver->major;
+
brd->dgap_major_transparent_print_registered = TRUE;
dgap_boards_by_major[brd->print_driver->major] = brd;
brd->dgap_transparent_print_major = brd->print_driver->major;

return rc;
+
+unregister_serial_drv:
+ tty_unregister_driver(brd->serial_driver);
+free_print_ttys:
+ kfree(brd->print_driver->ttys);
+ brd->print_driver->ttys = NULL;
+free_print_drv:
+ put_tty_driver(brd->print_driver);
+free_serial_ttys:
+ kfree(brd->serial_driver->ttys);
+ brd->serial_driver->ttys = NULL;
+free_serial_drv:
+ put_tty_driver(brd->serial_driver);
+
+ return rc;
}

/*
--
1.7.1