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| author |   Jiri Slaby <jslaby@suse.cz> | 2021-05-05 11:19:10 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-13 16:57:17 +0200 |
| commit | 19475209331168cdb8070a011650535f1c54a730 (patch) | |
| tree | 613d1921238f08ff1dec3a9999d19b299560fff3 /drivers/tty/tty_ldisc.c | |
| parent | tty: make tty_ldisc_ops a param in tty_unregister_ldisc (diff) | |
| download | linux-dev-19475209331168cdb8070a011650535f1c54a730.tar.xz linux-dev-19475209331168cdb8070a011650535f1c54a730.zip | |
tty: drop tty_ldisc_ops::refcount
The refcount is checked only in tty_unregister_ldisc and EBUSY returned
if it is nonzero. But none of the tty_unregister_ldisc callers act
anyhow if this (or any other) error is returned. So remove
tty_ldisc_ops::refcount completely and make tty_unregister_ldisc return
'void' in the next patches. That means we assume tty_unregister_ldisc is
not called while the ldisc might be in use. That relies on
try_module_get in get_ldops and module_put in put_ldops.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210505091928.22010-18-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_ldisc.c')
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index d02deeb5e584..98e8316fd28a 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -69,7 +69,6 @@ int tty_register_ldisc(struct tty_ldisc_ops *new_ldisc) raw_spin_lock_irqsave(&tty_ldiscs_lock, flags); tty_ldiscs[new_ldisc->num] = new_ldisc; - new_ldisc->refcount = 0; raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags); return ret; @@ -90,16 +89,12 @@ EXPORT_SYMBOL(tty_register_ldisc); int tty_unregister_ldisc(struct tty_ldisc_ops *ldisc) { unsigned long flags; - int ret = 0; raw_spin_lock_irqsave(&tty_ldiscs_lock, flags); - if (tty_ldiscs[ldisc->num]->refcount) - ret = -EBUSY; - else - tty_ldiscs[ldisc->num] = NULL; + tty_ldiscs[ldisc->num] = NULL; raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags); - return ret; + return 0; } EXPORT_SYMBOL(tty_unregister_ldisc); @@ -113,10 +108,8 @@ static struct tty_ldisc_ops *get_ldops(int disc) ldops = tty_ldiscs[disc]; if (ldops) { ret = ERR_PTR(-EAGAIN); - if (try_module_get(ldops->owner)) { - ldops->refcount++; + if (try_module_get(ldops->owner)) ret = ldops; - } } raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags); return ret; @@ -127,7 +120,6 @@ static void put_ldops(struct tty_ldisc_ops *ldops) unsigned long flags; raw_spin_lock_irqsave(&tty_ldiscs_lock, flags); - ldops->refcount--; module_put(ldops->owner); raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags); } |