staging: dgap: implement error handling in dgap_tty_register()

- 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>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/dgap/dgap.c b/drivers/staging/dgap/dgap.c
index d7cfc453e4f5e50d9ff9d61342ffa56201a6b209..8cf0816c0217537d53bee861b96cedcb4dd61787 100644 (file)
--- a/drivers/staging/dgap/dgap.c
+++ b/drivers/staging/dgap/dgap.c
@@ -1210,9 +1210,11 @@ static int dgap_ms_sleep(ulong ms)
  */
 static int dgap_tty_register(struct board_t *brd)
 {
-       int rc = 0;
+       int rc;
 
-       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_drv;
+       }
 
        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
@@ -1276,19 +1286,30 @@ 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_drv;
 
        /* 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 0;
+
+unregister_serial_drv:
+       tty_unregister_driver(brd->serial_driver);
+free_print_drv:
+       put_tty_driver(brd->print_driver);
+free_serial_drv:
+       put_tty_driver(brd->serial_driver);
+
        return rc;
 }