diff options
author | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-24 21:22:33 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-24 21:22:33 +0100 |
commit | baea7b946f00a291b166ccae7fcfed6c01530cc6 (patch) | |
tree | 4aa275fbdbec9c7b9b4629e8bee2bbecd3c6a6af /drivers/char/tty_ldisc.c | |
parent | ae19ffbadc1b2100285a5b5b3d0a4e0a11390904 (diff) | |
parent | 94e0fb086fc5663c38bbc0fe86d698be8314f82f (diff) |
Merge branch 'origin' into for-linus
Conflicts:
MAINTAINERS
Diffstat (limited to 'drivers/char/tty_ldisc.c')
-rw-r--r-- | drivers/char/tty_ldisc.c | 82 |
1 files changed, 42 insertions, 40 deletions
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index e48af9f7921..aafdbaebc16 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; } |