Commit a7e50de4 authored Jun 07, 2022 by Jiri Slaby Committed by Greg Kroah-Hartman Jun 10, 2022

tty/vt: consolemap: change refcount only if needed in con_do_clear_unimap()

con_do_clear_unimap() currently decreases and increases refcount of old
dictionary in a back and forth fashion. This makes the code really hard
to follow. Decrease the refcount only if everything went well and we
really allocated a new one and decoupled from the old dictionary.

I sincerelly hope I did not make a mistake in this (ill) logic.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220607104946.18710-33-jslaby@suse.cz

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d8d0d175

drivers/tty/vt/consolemap.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -535,22 +535,23 @@ static int con_do_clear_unimap(struct vc_data *vc)
		{
		struct uni_pagedict old = vc->vc_uni_pagedir_loc;

		if (!old \|\| --old->refcount) {
		if (!old \|\| old->refcount > 1) {
		struct uni_pagedict new = kzalloc(sizeof(new), GFP_KERNEL);
		if (!new) {
		if (old)
		old->refcount++;
		if (!new)
		return -ENOMEM;
		}

		new->refcount = 1;
		*vc->vc_uni_pagedir_loc = new;

		if (old)
		old->refcount--;
		} else {
		if (old == dflt)
		dflt = NULL;
		old->refcount++;
		old->sum = 0;
		con_release_unimap(old);
		}

		return 0;
		}