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um: line: Don't free winch (with IRQ) under spinlock

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Lockdep correctly complains that one shouldn't call um_free_irq()
with free_irq() inside under a spinlock since that will attempt
to acquire a mutex.

Rearrange the code to keep the list manipulations under the lock
while moving the actual freeing outside of it, to avoid this.

In particular, this removes the lockdep complaint at shutdown that
I was seeing with lockdep enabled.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: anton.ivanov@cambridgegreys.com
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Johannes Berg 2020-12-04 16:22:44 +01:00 committed by Richard Weinberger
parent fc6b6a872d
commit f4ab7818ef
1 changed files with 8 additions and 4 deletions
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12
arch/um/drivers/line.c
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@ -608,7 +608,6 @@ static void free_winch(struct winch *winch)
winch->fd = -1;
if (fd != -1)
os_close_file(fd);
list_del(&winch->list);
__free_winch(&winch->work);
}
@ -709,6 +708,8 @@ static void unregister_winch(struct tty_struct *tty)
winch = list_entry(ele, struct winch, list);
wtty = tty_port_tty_get(winch->port);
if (wtty == tty) {
list_del(&winch->list);
spin_unlock(&winch_handler_lock);
free_winch(winch);
break;
}
@ -719,14 +720,17 @@ static void unregister_winch(struct tty_struct *tty)
static void winch_cleanup(void)
{
struct list_head *ele, *next;
struct winch *winch;
spin_lock(&winch_handler_lock);
while ((winch = list_first_entry_or_null(&winch_handlers,
struct winch, list))) {
list_del(&winch->list);
spin_unlock(&winch_handler_lock);
list_for_each_safe(ele, next, &winch_handlers) {
winch = list_entry(ele, struct winch, list);
free_winch(winch);
spin_lock(&winch_handler_lock);
}
spin_unlock(&winch_handler_lock);