1 files changed, 42 insertions, 40 deletions

diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index e48af9f79219..aafdbaebc16a 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -145,48 +145,33 @@ int tty_unregister_ldisc(int disc)
 }
 EXPORT_SYMBOL(tty_unregister_ldisc);
 
-
-/**
- *      tty_ldisc_try_get       -       try and reference an ldisc
- *      @disc: ldisc number
- *
- *      Attempt to open and lock a line discipline into place. Return
- *      the line discipline refcounted or an error.
- */
-
-static struct tty_ldisc *tty_ldisc_try_get(int disc)
+static struct tty_ldisc_ops *get_ldops(int disc)
 {
         unsigned long flags;
-        struct tty_ldisc *ld;
-        struct tty_ldisc_ops *ldops;
-        int err = -EINVAL;
-
-        ld = kmalloc(sizeof(struct tty_ldisc), GFP_KERNEL);
-        if (ld == NULL)
-                return ERR_PTR(-ENOMEM);
+        struct tty_ldisc_ops *ldops, *ret;
 
         spin_lock_irqsave(&tty_ldisc_lock, flags);
-        ld->ops = NULL;
+        ret = ERR_PTR(-EINVAL);
         ldops = tty_ldiscs[disc];
-        /* Check the entry is defined */
         if (ldops) {
-                /* If the module is being unloaded we can't use it */
-                if (!try_module_get(ldops->owner))
-                        err = -EAGAIN;
-                else {
-                        /* lock it */
+                ret = ERR_PTR(-EAGAIN);
+                if (try_module_get(ldops->owner)) {
                         ldops->refcount++;
-                        ld->ops = ldops;
-                        atomic_set(&ld->users, 1);
-                        err = 0;
+                        ret = ldops;
                 }
         }
         spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-        if (err) {
-                kfree(ld);
-                return ERR_PTR(err);
-        }
-        return ld;
+        return ret;
+}
+
+static void put_ldops(struct tty_ldisc_ops *ldops)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&tty_ldisc_lock, flags);
+        ldops->refcount--;
+        module_put(ldops->owner);
+        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
 }
 
 /**
@@ -205,14 +190,31 @@ static struct tty_ldisc *tty_ldisc_try_get(int disc)
 static struct tty_ldisc *tty_ldisc_get(int disc)
 {
         struct tty_ldisc *ld;
+        struct tty_ldisc_ops *ldops;
 
         if (disc < N_TTY || disc >= NR_LDISCS)
                 return ERR_PTR(-EINVAL);
-        ld = tty_ldisc_try_get(disc);
-        if (IS_ERR(ld)) {
+
+        /*
+         * Get the ldisc ops - we may need to request them to be loaded
+         * dynamically and try again.
+         */
+        ldops = get_ldops(disc);
+        if (IS_ERR(ldops)) {
                 request_module("tty-ldisc-%d", disc);
-                ld = tty_ldisc_try_get(disc);
+                ldops = get_ldops(disc);
+                if (IS_ERR(ldops))
+                        return ERR_CAST(ldops);
         }
+
+        ld = kmalloc(sizeof(struct tty_ldisc), GFP_KERNEL);
+        if (ld == NULL) {
+                put_ldops(ldops);
+                return ERR_PTR(-ENOMEM);
+        }
+
+        ld->ops = ldops;
+        atomic_set(&ld->users, 1);
         return ld;
 }
 
@@ -234,13 +236,13 @@ static void tty_ldiscs_seq_stop(struct seq_file *m, void *v)
 static int tty_ldiscs_seq_show(struct seq_file *m, void *v)
 {
         int i = *(loff_t *)v;
-        struct tty_ldisc *ld;
+        struct tty_ldisc_ops *ldops;
 
-        ld = tty_ldisc_try_get(i);
-        if (IS_ERR(ld))
+        ldops = get_ldops(i);
+        if (IS_ERR(ldops))
                 return 0;
-        seq_printf(m, "%-10s %2d\n", ld->ops->name ? ld->ops->name : "???", i);
-        put_ldisc(ld);
+        seq_printf(m, "%-10s %2d\n", ldops->name ? ldops->name : "???", i);
+        put_ldops(ldops);
         return 0;
 }